Applying boron nitride on bullets
- Thread starter btm_54
- Start date
I've found its much much easier to apply than either moly or WS2. Foolproof actually.
I've always had issues applying moly or WS2. Mostly because my bullet coating equipment is in a humid basement. Had to jump through hoops to get consistent coatings.
HBN in the same basement is easy. No bullet wash, no impacting media needed. Just dump some bullets in a vibratory tumbler, throw how ever much HBN I feel like in, screw cover on and let it run.
I have a large plastic mixing bowl. Place a towel or old t-shirt across the top of it. Dump the tumbled bullets on top the cloth and shake em around like your panning for gold. Done!!!
I've always had issues applying moly or WS2. Mostly because my bullet coating equipment is in a humid basement. Had to jump through hoops to get consistent coatings.
HBN in the same basement is easy. No bullet wash, no impacting media needed. Just dump some bullets in a vibratory tumbler, throw how ever much HBN I feel like in, screw cover on and let it run.
I have a large plastic mixing bowl. Place a towel or old t-shirt across the top of it. Dump the tumbled bullets on top the cloth and shake em around like your panning for gold. Done!!!
A lot of us have been using HbN with none of the ill effects you commonly post on various forums, I'm starting to beleave you have a problem with HbN, please tell us of your personnel experiences, not stuff you have read about on the internet.
If you're talking to me you're barking up the wrong tree. What would make you think I have a problem with hBN??
I use it exclusively on every rifle in the armory save one, and have a couple of ways to do it.
I took a piece of 1/2" thick Sintra (expanded PVC), routed a channel on the back to fit exactly over the rim of a tumbler, cut two holes the exact size of the lower 1/3rd of two plastic jars and cut a center hole for the shaft and wing-nut. (no comments, Will)
Slide the jars in till they're tight, add the .177 steel balls and impact coat. You can even leave the media in the bowl if you want to clean brass at the same time.
This setup keeps the center of gravity low and the shaking is much harder and sharper without the cushion of small jars floating in the media.
Tumbler with jars removed. The media is inside so we can do brass at the same time as impact coating.
Dedicated vibrator tumbler, 4 plastic jars, 4"x2.5", 1/3rd fiilled with previously impact coated .177 steel BBs, 10 to 25 175SMKs, .6gr of negative 5 micron hBN or (if you're doing Moly) 1 heaping teaspoon of Lab Grade Moly, 99.9% 1 to 3 micron size.
1/2" thick dense foam padding below, sides and on top compression trapping all four jars. NO media.
Tighten top and vibrate for 3 hours.
And another sequence.
-------------------------------------------------------------
Now it begins.
Ball and Bullet washing.
Hot, soapy water.
Now they dry overnight on a Terry Towel.
The steel balls and bullets were brand new right out of the box, but after washing, the water was grey and dirty.
More to come with the next process.
P
------------------------------------------------------------------------------------------
The BBS in the tumbler jars. One for .30 caliber and one for the 22-250 projectiles.
The bHN impact coated 175s , frosted looking right out of the jar.
After rolling in a terry towel, you can see the satin finish.
-----------------------------------------------------------------------------------------
Use a Release Magnet to carefully collect the hBN coated steel BBs and place them back in the plastic jar. Seal immediately.
And after finding another very short sentence in the Patent, the process has now changed a bit.
-----------------------------------------------------------------------------
Correspondence between Dad and one of the original process developers.
XXXXXX,
What you are doing sounds just like what I am doing. I use 3 grains of hBN for 50 (30 caliber 175 gr SMK) 3 grains for of hBN for 67 (6mm 107 gr SMK) and 3 grains of hBN for 100 (223 caliber 80 gr SMK). Thumble for 3 hours. The coating is very thin and seems to work okay.
Happy Shooting,
Larry
Swiss Products wrote:
Larry, my name is XXXXXX XX XXXXX. My son and I have been working with hBN and Sierra MK175gr projectiles in a Swiss zfk55 Sniper rifle. Can you tell me exactly what hBN grain weight you found the most effective with 100 of your 6mm projectiles? We're currenly using 4gr hBN in a P-nut butter jar 1/3 full of coated BBs and 100 projectiles tumbled for 3 hours in a Thumler's tumlber. Are we headed the right direction.
Thanks for any help.
P
That, and a short sentence in the original Patent now has us using a new, smaller dedicated vibrator tumbler, 4 seperate plastic jars on their sides without tumbling media, but rather wedged tightly in place with 1/2" dense foam sheeting and top compressed as well.
The projectiles and BBs are now vibrating faster with a lot more impact. The objective is to create as many impact points as possible and maintain a thin coat of hBN.
------------------------------------------------------
Sound like I have a problem? My post was to let him know there is a barrel finish that does not lend itself to the hBN process.
We have a new development since all of the previous was written. Our projectiles have a far more solid and even coating than you've been seeing on the net. I'll post it later tomorrow. In essence, our process with hBN has taken nominal 1.5" moa rifles and tightened them right up to sub-moa. There are some 25 rifles involved in this process.
Wrong tree, bud.
zfk55
I use it exclusively on every rifle in the armory save one, and have a couple of ways to do it.
I took a piece of 1/2" thick Sintra (expanded PVC), routed a channel on the back to fit exactly over the rim of a tumbler, cut two holes the exact size of the lower 1/3rd of two plastic jars and cut a center hole for the shaft and wing-nut. (no comments, Will)
Slide the jars in till they're tight, add the .177 steel balls and impact coat. You can even leave the media in the bowl if you want to clean brass at the same time.
This setup keeps the center of gravity low and the shaking is much harder and sharper without the cushion of small jars floating in the media.
Tumbler with jars removed. The media is inside so we can do brass at the same time as impact coating.
Dedicated vibrator tumbler, 4 plastic jars, 4"x2.5", 1/3rd fiilled with previously impact coated .177 steel BBs, 10 to 25 175SMKs, .6gr of negative 5 micron hBN or (if you're doing Moly) 1 heaping teaspoon of Lab Grade Moly, 99.9% 1 to 3 micron size.
1/2" thick dense foam padding below, sides and on top compression trapping all four jars. NO media.
Tighten top and vibrate for 3 hours.
And another sequence.
-------------------------------------------------------------
Now it begins.
Ball and Bullet washing.
Hot, soapy water.
Now they dry overnight on a Terry Towel.
The steel balls and bullets were brand new right out of the box, but after washing, the water was grey and dirty.
More to come with the next process.
P
------------------------------------------------------------------------------------------
The BBS in the tumbler jars. One for .30 caliber and one for the 22-250 projectiles.
The bHN impact coated 175s , frosted looking right out of the jar.
After rolling in a terry towel, you can see the satin finish.
-----------------------------------------------------------------------------------------
Use a Release Magnet to carefully collect the hBN coated steel BBs and place them back in the plastic jar. Seal immediately.
And after finding another very short sentence in the Patent, the process has now changed a bit.
-----------------------------------------------------------------------------
Correspondence between Dad and one of the original process developers.
XXXXXX,
What you are doing sounds just like what I am doing. I use 3 grains of hBN for 50 (30 caliber 175 gr SMK) 3 grains for of hBN for 67 (6mm 107 gr SMK) and 3 grains of hBN for 100 (223 caliber 80 gr SMK). Thumble for 3 hours. The coating is very thin and seems to work okay.
Happy Shooting,
Larry
Swiss Products wrote:
Larry, my name is XXXXXX XX XXXXX. My son and I have been working with hBN and Sierra MK175gr projectiles in a Swiss zfk55 Sniper rifle. Can you tell me exactly what hBN grain weight you found the most effective with 100 of your 6mm projectiles? We're currenly using 4gr hBN in a P-nut butter jar 1/3 full of coated BBs and 100 projectiles tumbled for 3 hours in a Thumler's tumlber. Are we headed the right direction.
Thanks for any help.
P
That, and a short sentence in the original Patent now has us using a new, smaller dedicated vibrator tumbler, 4 seperate plastic jars on their sides without tumbling media, but rather wedged tightly in place with 1/2" dense foam sheeting and top compressed as well.
The projectiles and BBs are now vibrating faster with a lot more impact. The objective is to create as many impact points as possible and maintain a thin coat of hBN.
------------------------------------------------------
Sound like I have a problem? My post was to let him know there is a barrel finish that does not lend itself to the hBN process.
We have a new development since all of the previous was written. Our projectiles have a far more solid and even coating than you've been seeing on the net. I'll post it later tomorrow. In essence, our process with hBN has taken nominal 1.5" moa rifles and tightened them right up to sub-moa. There are some 25 rifles involved in this process.
Wrong tree, bud.
zfk55
And this one is our Moly process.
We use large pharmace pill bottles for these. They're large and hold a greater number of BBs and bullets.
He took a piece of 1/2" thick Sintra (expanded PVC), routed a channel on the back to fit exactly over the rim of a tumbler, cut two holes the exact size of the lower 1/3rd of two plastic jars and cut a center hole for the shaft and wing-nut. Slide the jars in till they're tight, add the .177 steel balls and impact coat. You can even leave the media in the bowl if you want to clean brass at the same time.
This setup keeps the center of gravity low and the shaking is much harder and sharper without the cushion of small jars floating in the media. This is the way to truly impact coat.
.177 steel balls into the bottom 1/3rd of the 4.5"x7" plastic container with two full teaspoons of 99.8% 1-3 Micron Lab Grade Moly and vibrated for 3 full hours.
Add 50 to 75 175gr SMKs (handle with gloves only) into the jar with a full, heaping teaspoon of Moly and vibrate for a full 3 hours. You can't (within reason) use too much Moly. The excess
stays in the jars and after removing the projectiles you shake the closed jar vigorously to remix the impact BBs and the excess Moly. For 25 to 75 projectiles per jar a pinch isn't going to do it properly.
After 3 hours remove them with a slotted spoon. They'll look rough like this.
Now an important part. Do not do the shredded paper towel method of cleaning. Try using corn cob. The dwell time in the corn cob will be
critical to performance, and not all barrel steel is the same. Do control groups of 5 to 10 (as we do) bullets at 2, 3, and 4 minutes in the corncob. Use similar jars
for the corn cob.
Remove them with a clean slotted spoon and bag them with a note on the dwell time of that group.
Polish them lightly with a rag and they should look like this,... very smooth, solid deep pewter blue color and you should not be able to
scratch the Moly from the surface with your fingernail.
Clean your barrel after every shooting session before you put it away. I don't care what you've heard, if you value your rifle.. clean it!
Moly can and will trap moisture between itself and the barrel and an immediate slow corrosion will begin if there is moisture present.
Everyone shooting Moly projectiles has their own methodology and some of them are inflexible for them. This is ours. We're flexible.
Maintaining flexibility is to learn, and continual learning is healthy.
Chrono your control groups. Reload safely, remove all reloading variables in your methodology, shoot safe and......... Stay low.
--------------------------------------------------------------------
We have a better process for this since that posting. I'll post it later today or in the morning. Nothing negative from us, Brian.
zfk55
We use large pharmace pill bottles for these. They're large and hold a greater number of BBs and bullets.
He took a piece of 1/2" thick Sintra (expanded PVC), routed a channel on the back to fit exactly over the rim of a tumbler, cut two holes the exact size of the lower 1/3rd of two plastic jars and cut a center hole for the shaft and wing-nut. Slide the jars in till they're tight, add the .177 steel balls and impact coat. You can even leave the media in the bowl if you want to clean brass at the same time.
This setup keeps the center of gravity low and the shaking is much harder and sharper without the cushion of small jars floating in the media. This is the way to truly impact coat.
.177 steel balls into the bottom 1/3rd of the 4.5"x7" plastic container with two full teaspoons of 99.8% 1-3 Micron Lab Grade Moly and vibrated for 3 full hours.
Add 50 to 75 175gr SMKs (handle with gloves only) into the jar with a full, heaping teaspoon of Moly and vibrate for a full 3 hours. You can't (within reason) use too much Moly. The excess
stays in the jars and after removing the projectiles you shake the closed jar vigorously to remix the impact BBs and the excess Moly. For 25 to 75 projectiles per jar a pinch isn't going to do it properly.
After 3 hours remove them with a slotted spoon. They'll look rough like this.
Now an important part. Do not do the shredded paper towel method of cleaning. Try using corn cob. The dwell time in the corn cob will be
critical to performance, and not all barrel steel is the same. Do control groups of 5 to 10 (as we do) bullets at 2, 3, and 4 minutes in the corncob. Use similar jars
for the corn cob.
Remove them with a clean slotted spoon and bag them with a note on the dwell time of that group.
Polish them lightly with a rag and they should look like this,... very smooth, solid deep pewter blue color and you should not be able to
scratch the Moly from the surface with your fingernail.
Clean your barrel after every shooting session before you put it away. I don't care what you've heard, if you value your rifle.. clean it!
Moly can and will trap moisture between itself and the barrel and an immediate slow corrosion will begin if there is moisture present.
Everyone shooting Moly projectiles has their own methodology and some of them are inflexible for them. This is ours. We're flexible.
Maintaining flexibility is to learn, and continual learning is healthy.
Chrono your control groups. Reload safely, remove all reloading variables in your methodology, shoot safe and......... Stay low.
--------------------------------------------------------------------
We have a better process for this since that posting. I'll post it later today or in the morning. Nothing negative from us, Brian.
zfk55
And.... one excerpt from us on hBN barrel prep.
--------------------------------------------------------------------
We're not, but if you want to send yours to me I'll coat them for you Matt. You'll have to do your barrel.
(From Dad's info)
Clean the bore/chamber/throat with Wipe Out or a like non-ammonia based copper remover. Use a carbon remover specific like Montana Extreme or a like carbon remover in the chamber and throat.
If you have one, inspect the bore for complete copper removal with a bore scope.
If not, be safe and use the Wipe Out with a nylon bristle brush, working up a heavy foam and let stand for a few hours.
Dry clean completley with patches or clean swabs.
Take a new .30 caliber cotton swab, or take your old ones and run them through the laundry or dishwasher. Dry completely.
Short switch back to square one:
You'll get your hBN in a container with a plastic, tape seal around the outside. Open it with extreme care and only long enough to fill a small, sealable pill bottle 1/3rd full. Re-seal the container immediately. Re-apply the exterior tape seal fully and tightly. Store at room temps in a secure place. Spill that container in a room in the house and your wife will be using a bat on you for weeks to come.
(No, I didn't, and my wife uses Darning Eggs instead of bats)
Screw the swab to the end of a cleaning rod just long enough to run the bore, open the hBN pill bottle, carefully roll the swab in the hBN, (close the hBN bottle immediately) insert into the bore from the breech end if possible. If your rifle won't acommodate taht, run it from the muzzle end. Go all the way through and then work it gently back and forth while slowly withdrawing the swab.
Once its out, leave it alone. The first few impact coated projectiles fired through the bore will do the ceramic coating for you, and that's it. You've done it. From that point on fire only impact coated projectiles through that rifle. Cleaning is done with dry patches, no chemicals at all.
For the chamber/throat area, use the right sized swab to fit into each and use Montana Extreme or a like carbon remover. Don't run any cleaning solvents down the bore.
If you feel the need to do that once in a while, cool...... but make sure you use the clean swab and hBN process again. It only takes a few minutes. I unscrew the swab and keep it inside the pill bottle so that it remains uncontaiminated.
To understand how it works, save me a bunch of typing and read the patent.
........................................................................................
BTW, Brian, this from the patent is why I gave the OP a caution on barrel type, and its dead on. Don't ask how I know and how many wasted projectiles. :
---------------------------------------------------------------------------
This is the description of the barrel that eventaully was the cause of withdrawing this particular rifle from the hBN process.
-----------------------------------------------------------------------------
The process on the barrel, probably requires some explanation. All of the properties applied, from the parent barrel material to the finishing process (electro-polishing) inclusive of the taper bore (there is a slight taper from breach to muzzle - about .0006" , that's six ten thousandths of an inch.) This achieves a couple of desired conditions: 1) linearization of the surface molecules of the bore surface {as you no doubt are aware from your machine tool background, every time a cutting tool touches the material a 'crust' is formed. This crust is what "barrel break in" is meant to correct. This is also, why 'break in' is minimal on your barrel}. Secondly, the taper configuration of the barrel, in affect, creates a freebore situation for the entire barrel length. Or, another way of looking at it is the barrel achieves a more uniform, or normalization condition for the bullet being pushed down the bore. All this achieves more even or consistent muzzle velocities which tightens standard deviation.
--------------------------------------------------------------------------
This is an excerpt from us concerning that discovery.
--------------------------------------------------------------------------
Edge, as of today the Wilson AR10 is no longer in the mix. Unable to get anything better than a .624 and moa I did more answer searching and actually unintentionally stumbled on the answer this afternoon, and it wasn't one I was expecting.
The Wilson's barrel is made of 17-4 Stainless Steel and is Electro Polished, and therein lies the problem. A brief conversation with a Stanford Chemicals rep disclosed the fact that the bore in this particluar rifle will not allow the submicron hBN to sufficiently embed itself into the steel to produce the desired results. The zfk55 Swiss Sniper will now be the control rifle for other Swiss firearms and my Son's other AR10s and various rifles. Those barrels all have bore surfaces suitable for hBN sub-micron penetration.
In addition to the above, I found this in the patent and obviously had not paid close enough attention. This is something my Son asked as well and apparently I wasn't listening to him closely enough either.
------------------------------------------------------------------------------------------------
We've made a few errors, but they've also been resolved. Of the two ways to impact coat we prefer the peanut butter jar in the Thumler's Tumbler. Using the smaller of the two jar sizes, fill it 1/4 full with the BBs. Add 2 grains of hBN and tumble it for an hour. This link is where we began, but we didn't follow the directions specifically. Ours works better for us. This also shows the use of smaller pill bottles, but they're also for smaller projectiles. We clean the coated projectiles by rolling them back and forth in a large Terry cloth towel.
http://www.6mmbr.com/bulletcoating.html
After the BBs were coated, we added 100 175gr Sierra MKs and another 2.5gr of hBN. This amount was tumbled for two hours. The results were exactly what we expected with the first group, but then...... I made a judgement error.
I continued reading and searching the net for anything we had missed and read a few posts by frequent users that indicated I was using far too little hBN. I changed the formula and proceeded to waste a lot of time and projectiles. After a lot of frustrating 1" and 1"+ groups I went back to the original patent page and found a small poaragraph I had either overlooked or forgotten in all of the very dry reading.
This is the page.... http://www.patentstorm.us/patents/7197986/description.html
And this is the all important paragraph:
Secondary Ion Mass Spectrometry (SIMS) testing performed on the surfaces of the internal bore of gun barrels shows that the boron nitride powder used in accordance with the present invention results in the ceramic powder particulates beingclearly embedded within the grain boundaries of the metal gun barrel. These test results show that burnishing sub-micron particulate ceramic is effective, and that continued firing of uncoated bullets will continue to experience the advantages of thepresent invention for an extended period of time. Such testing also shows that excessively coating boron nitride powder onto bullets provides erratic results and sometimes no velocity improvement. Thinner coating on the bullets provides more consistent velocity improvement
Now I have a nominal 900 projectiles to re-clean in a sonic vibrator with denatured alcohol. Its going to be a long Sunday.
Those that tell you "One inch ? Big deal. I do better than that with my .308 bolt action."
Yeah, but remind them that we're talking semi-auto, not bolt action, and we've gotten .64moa with our best 5 round groups thus far.
I'll answer whatever I can for you, just ask. For the moment I'm headed for the reloading room to continue cleaning over hBN'd projectiles. Sheesh..........
P
---------------------------------------------------------------------------------------
I have no clue as to why they say that. The chronograph doesn't lie and we experienced an immediate increase in velocity with the same projectile and same load.
The Wilson is a guaranteed moa at 1,000 yards using Moly. He's done this for years and we were able to demonstrate that the correctly hBN coated projectiles equaled his accuracy the first day. My error was in reading info from a lot of other users who used more hBN in the process, and by increasing the hBN amount and impact coating time I created a situation as described in the patent. Too much hBN causes erratic results. We also didn't wipe them down properly. We just rolled them in a large Terry towel, and that left too much reside on the bullets.
For us, its increased accuracy, a faster bullet supersonic out beyond 1,000 yards and extended barrel life. If you're nervous, wait a few days till our final results are achieved. Wait till we're at the end conclusion and I'll have a bit more info for you soon.
BTW........ If you can smell the hBN, you're too close to it. Don't sniff the jar! .... and do the BB/projectile separation outside, not in the reloading room. That odor is the sub-micron particles themselves entering your nose. Go back and re-read the sequence at the beginning of this thread in its entirety.
P
----------------------------------------------------------------
Here's where we are, Edge. 5 round group minimums.
1/2"moa. We went through both RE15 and 4064 in 1/2gr increments. We suspected that Wilson shooting at sea level with us at 4,000 feet was going to make a difference in his load data, and we were right. 4064 is moa for sure, but the RE15 produced tigher groups. We checked LC against Win brass, but truth be told we think this shiney LC is machine gun brass. We'll be buying some brand new LC next week. Unfotunate that I have around 2,000 LC supposedly once-fired, but now I'm suspicious.
Lat forgot his camera so we'll save that for the 300 and 500 yard shots. Onhce we're truly happy we'll go down the valley for 1,000 yard shooting.
The process ended up being 100 new Sierra MK 175s in the 5" peanut butter jar filled to the 1/3 mark with steel impact coated BBs. Add 2.5gr of hBN and tumble in a Thumler's Tumbler for 3 hours. I know all about all of the posts about amount and dwell time, but after some 350 projectiles coated at varilous amounts, dwell time and sent down range, this is our current opinion. That's not to say we won't mess around with both factors this fall, but at 1/2"moa with a .308 sem-auto I'm not going to complain.
One more session this afternoon, and I'll keep you posted.
Another discovery excerpt.
------------------------------------------------------------------------------
Hidden within a huge mass of the manufaturer's information was this......
By Tumbling/Vibratory bowl coatingThis method is ideal for bullets and other small parts.
Speed and friction determine how effectively the material bonds to the part. The greater the speed and the pressure of application, the greater the bond.
Correct Method is:
Clean and degrease the part. Take 5-6 small empty plastic bottles (empty aspirin bottles will do). Put few parts in the bottle and fill the bottle (up to 75%) with WS2 powder and steel BBs. Fill all bottles likewise. Put the bottles in vibratory bowl/tumbler with sand, vibratory media or with the bottles wedged.. Vibrate/Tumble for 4-5 hours. Empty the bottles (you can reuse WS2) and wipe clean the parts with soft tissue/cloth.
We could have saved 275 bullets if we had found this a month ago!
After 5 hours of vibrating, the 175SMKs feel and look quite different than any of the previous attempts.
-----------------------------------------------------------------------------
All of the above has now been resolved by us for our applications. I'll post current progress here in a few days. We're very determined to prove the hBN process to ourselves across a broad spectrum of applications, so............
Waddaya think, Brian? Am I anti-hBN?? ;D
zfk55
--------------------------------------------------------------------
We're not, but if you want to send yours to me I'll coat them for you Matt. You'll have to do your barrel.
(From Dad's info)
Clean the bore/chamber/throat with Wipe Out or a like non-ammonia based copper remover. Use a carbon remover specific like Montana Extreme or a like carbon remover in the chamber and throat.
If you have one, inspect the bore for complete copper removal with a bore scope.
If not, be safe and use the Wipe Out with a nylon bristle brush, working up a heavy foam and let stand for a few hours.
Dry clean completley with patches or clean swabs.
Take a new .30 caliber cotton swab, or take your old ones and run them through the laundry or dishwasher. Dry completely.
Short switch back to square one:
You'll get your hBN in a container with a plastic, tape seal around the outside. Open it with extreme care and only long enough to fill a small, sealable pill bottle 1/3rd full. Re-seal the container immediately. Re-apply the exterior tape seal fully and tightly. Store at room temps in a secure place. Spill that container in a room in the house and your wife will be using a bat on you for weeks to come.
(No, I didn't, and my wife uses Darning Eggs instead of bats)
Screw the swab to the end of a cleaning rod just long enough to run the bore, open the hBN pill bottle, carefully roll the swab in the hBN, (close the hBN bottle immediately) insert into the bore from the breech end if possible. If your rifle won't acommodate taht, run it from the muzzle end. Go all the way through and then work it gently back and forth while slowly withdrawing the swab.
Once its out, leave it alone. The first few impact coated projectiles fired through the bore will do the ceramic coating for you, and that's it. You've done it. From that point on fire only impact coated projectiles through that rifle. Cleaning is done with dry patches, no chemicals at all.
For the chamber/throat area, use the right sized swab to fit into each and use Montana Extreme or a like carbon remover. Don't run any cleaning solvents down the bore.
If you feel the need to do that once in a while, cool...... but make sure you use the clean swab and hBN process again. It only takes a few minutes. I unscrew the swab and keep it inside the pill bottle so that it remains uncontaiminated.
To understand how it works, save me a bunch of typing and read the patent.
........................................................................................
BTW, Brian, this from the patent is why I gave the OP a caution on barrel type, and its dead on. Don't ask how I know and how many wasted projectiles. :
---------------------------------------------------------------------------
This is the description of the barrel that eventaully was the cause of withdrawing this particular rifle from the hBN process.
-----------------------------------------------------------------------------
The process on the barrel, probably requires some explanation. All of the properties applied, from the parent barrel material to the finishing process (electro-polishing) inclusive of the taper bore (there is a slight taper from breach to muzzle - about .0006" , that's six ten thousandths of an inch.) This achieves a couple of desired conditions: 1) linearization of the surface molecules of the bore surface {as you no doubt are aware from your machine tool background, every time a cutting tool touches the material a 'crust' is formed. This crust is what "barrel break in" is meant to correct. This is also, why 'break in' is minimal on your barrel}. Secondly, the taper configuration of the barrel, in affect, creates a freebore situation for the entire barrel length. Or, another way of looking at it is the barrel achieves a more uniform, or normalization condition for the bullet being pushed down the bore. All this achieves more even or consistent muzzle velocities which tightens standard deviation.
--------------------------------------------------------------------------
This is an excerpt from us concerning that discovery.
--------------------------------------------------------------------------
Edge, as of today the Wilson AR10 is no longer in the mix. Unable to get anything better than a .624 and moa I did more answer searching and actually unintentionally stumbled on the answer this afternoon, and it wasn't one I was expecting.
The Wilson's barrel is made of 17-4 Stainless Steel and is Electro Polished, and therein lies the problem. A brief conversation with a Stanford Chemicals rep disclosed the fact that the bore in this particluar rifle will not allow the submicron hBN to sufficiently embed itself into the steel to produce the desired results. The zfk55 Swiss Sniper will now be the control rifle for other Swiss firearms and my Son's other AR10s and various rifles. Those barrels all have bore surfaces suitable for hBN sub-micron penetration.
In addition to the above, I found this in the patent and obviously had not paid close enough attention. This is something my Son asked as well and apparently I wasn't listening to him closely enough either.
------------------------------------------------------------------------------------------------
We've made a few errors, but they've also been resolved. Of the two ways to impact coat we prefer the peanut butter jar in the Thumler's Tumbler. Using the smaller of the two jar sizes, fill it 1/4 full with the BBs. Add 2 grains of hBN and tumble it for an hour. This link is where we began, but we didn't follow the directions specifically. Ours works better for us. This also shows the use of smaller pill bottles, but they're also for smaller projectiles. We clean the coated projectiles by rolling them back and forth in a large Terry cloth towel.
http://www.6mmbr.com/bulletcoating.html
After the BBs were coated, we added 100 175gr Sierra MKs and another 2.5gr of hBN. This amount was tumbled for two hours. The results were exactly what we expected with the first group, but then...... I made a judgement error.
I continued reading and searching the net for anything we had missed and read a few posts by frequent users that indicated I was using far too little hBN. I changed the formula and proceeded to waste a lot of time and projectiles. After a lot of frustrating 1" and 1"+ groups I went back to the original patent page and found a small poaragraph I had either overlooked or forgotten in all of the very dry reading.
This is the page.... http://www.patentstorm.us/patents/7197986/description.html
And this is the all important paragraph:
Secondary Ion Mass Spectrometry (SIMS) testing performed on the surfaces of the internal bore of gun barrels shows that the boron nitride powder used in accordance with the present invention results in the ceramic powder particulates beingclearly embedded within the grain boundaries of the metal gun barrel. These test results show that burnishing sub-micron particulate ceramic is effective, and that continued firing of uncoated bullets will continue to experience the advantages of thepresent invention for an extended period of time. Such testing also shows that excessively coating boron nitride powder onto bullets provides erratic results and sometimes no velocity improvement. Thinner coating on the bullets provides more consistent velocity improvement
Now I have a nominal 900 projectiles to re-clean in a sonic vibrator with denatured alcohol. Its going to be a long Sunday.
Those that tell you "One inch ? Big deal. I do better than that with my .308 bolt action."
Yeah, but remind them that we're talking semi-auto, not bolt action, and we've gotten .64moa with our best 5 round groups thus far.
I'll answer whatever I can for you, just ask. For the moment I'm headed for the reloading room to continue cleaning over hBN'd projectiles. Sheesh..........
P
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I have no clue as to why they say that. The chronograph doesn't lie and we experienced an immediate increase in velocity with the same projectile and same load.
The Wilson is a guaranteed moa at 1,000 yards using Moly. He's done this for years and we were able to demonstrate that the correctly hBN coated projectiles equaled his accuracy the first day. My error was in reading info from a lot of other users who used more hBN in the process, and by increasing the hBN amount and impact coating time I created a situation as described in the patent. Too much hBN causes erratic results. We also didn't wipe them down properly. We just rolled them in a large Terry towel, and that left too much reside on the bullets.
For us, its increased accuracy, a faster bullet supersonic out beyond 1,000 yards and extended barrel life. If you're nervous, wait a few days till our final results are achieved. Wait till we're at the end conclusion and I'll have a bit more info for you soon.
BTW........ If you can smell the hBN, you're too close to it. Don't sniff the jar! .... and do the BB/projectile separation outside, not in the reloading room. That odor is the sub-micron particles themselves entering your nose. Go back and re-read the sequence at the beginning of this thread in its entirety.
P
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Here's where we are, Edge. 5 round group minimums.
1/2"moa. We went through both RE15 and 4064 in 1/2gr increments. We suspected that Wilson shooting at sea level with us at 4,000 feet was going to make a difference in his load data, and we were right. 4064 is moa for sure, but the RE15 produced tigher groups. We checked LC against Win brass, but truth be told we think this shiney LC is machine gun brass. We'll be buying some brand new LC next week. Unfotunate that I have around 2,000 LC supposedly once-fired, but now I'm suspicious.
Lat forgot his camera so we'll save that for the 300 and 500 yard shots. Onhce we're truly happy we'll go down the valley for 1,000 yard shooting.
The process ended up being 100 new Sierra MK 175s in the 5" peanut butter jar filled to the 1/3 mark with steel impact coated BBs. Add 2.5gr of hBN and tumble in a Thumler's Tumbler for 3 hours. I know all about all of the posts about amount and dwell time, but after some 350 projectiles coated at varilous amounts, dwell time and sent down range, this is our current opinion. That's not to say we won't mess around with both factors this fall, but at 1/2"moa with a .308 sem-auto I'm not going to complain.
One more session this afternoon, and I'll keep you posted.
Another discovery excerpt.
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Hidden within a huge mass of the manufaturer's information was this......
By Tumbling/Vibratory bowl coatingThis method is ideal for bullets and other small parts.
Speed and friction determine how effectively the material bonds to the part. The greater the speed and the pressure of application, the greater the bond.
Correct Method is:
Clean and degrease the part. Take 5-6 small empty plastic bottles (empty aspirin bottles will do). Put few parts in the bottle and fill the bottle (up to 75%) with WS2 powder and steel BBs. Fill all bottles likewise. Put the bottles in vibratory bowl/tumbler with sand, vibratory media or with the bottles wedged.. Vibrate/Tumble for 4-5 hours. Empty the bottles (you can reuse WS2) and wipe clean the parts with soft tissue/cloth.
We could have saved 275 bullets if we had found this a month ago!
After 5 hours of vibrating, the 175SMKs feel and look quite different than any of the previous attempts.
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All of the above has now been resolved by us for our applications. I'll post current progress here in a few days. We're very determined to prove the hBN process to ourselves across a broad spectrum of applications, so............
Waddaya think, Brian? Am I anti-hBN?? ;D
zfk55
The Dillon Commercial with the custom top made in the shop with our CNC. Accepts 4 ea 4.5" x 5.5" sealable jars. Two are for Moly and two are for corncob. The center of gravity is kept low and the heavy duty motor provides maximum impact.
The Frankfort vibrator, padded with dense foam accepts two medium sized P-nut butter jars. They're both trapped between dense foam top and bottom. Without medium in the vibrator the maximum impact is achieved.
Still working with rifles and calibers, and I hope this helped someone. We're huge hBN fans.
zfk55
The Frankfort vibrator, padded with dense foam accepts two medium sized P-nut butter jars. They're both trapped between dense foam top and bottom. Without medium in the vibrator the maximum impact is achieved.
Still working with rifles and calibers, and I hope this helped someone. We're huge hBN fans.
zfk55
I find this process very interesting and have ordered me some hbn. For the coating process has anyone tried using a barrel tumbler instead of a vibrator? Reason for asking is I have a dedicated barrel tumbler that was used for moly coating years ago but I no longer use moly. Would I get enough impact for the coating process? Thanks for any info you can give me. Tim
GSPV
A failure to plan is a plan for failure.
I use the Lyman Moly Kit and just use HBN rather than the moly. Seems to work fine.
See: http://www.accurateshooter.com/forum/index.php/topic,3741604.0.html .
I used 70nm HBN in 91% alcohol to swap the barrel before break in. I've repeated it each time I clean it after shooting. Might not do anything for HBN treatment, but that first bullet goes right into the group.
FWIW,
See: http://www.accurateshooter.com/forum/index.php/topic,3741604.0.html .
I used 70nm HBN in 91% alcohol to swap the barrel before break in. I've repeated it each time I clean it after shooting. Might not do anything for HBN treatment, but that first bullet goes right into the group.
FWIW,
Word to the wise. Wear a good filtering device while handleing hbn. You can get a respiratory condition(infection) if inhaled. Tim
I have apologized to zfk55 in a PM, now I wish to do it here, I am sorry that I called you out, while I have been HbN coating 155Scenars, I now beleave that because of zfk55 I have a better understanding(somethings I still don't understand) of the whole process and it's uses, again I am sorry.
Could anyone explain why the patent suggests coating bullets should result in increased velocities? hBN reduces friction, so just as with moly if you're doing it right shouldn't you get lower muzzle velocities from the same loads?
Just stumbled on this post, WOW! Nice work Z
A little clarification can be given to what happens if you have too much HBN on your bullets. I started with naked bullets then switched over. In my 300WM and 338LM I was getting a lot of vertical stringing. I was just impact coating them in an old midway tumbler with bb’s in it. I only kind of wiped them off. At 100yds it was not very noticeable. As distance increased it was very noticeable. Now I wipe them down with the same rag that has tones of HBN on it. Now when I shoot either rifle at distance they have very little vertical to them at all.
I just to bring the crono with ever time I go shooting so I can get a reading on my 338lm. My 300WM is giving very stable readings right around the 3015fps mark with 220gr SMK.
I just to bring the crono with ever time I go shooting so I can get a reading on my 338lm. My 300WM is giving very stable readings right around the 3015fps mark with 220gr SMK.
Ok a dumb question. Why coat bullets with boron nitride ? What are the benefits ? Thought molly coating was on its way out ?
All of the benefits of moly: Reduced fouling, reduced barrel wear, reduced barrel heating -- in general the ability to shoot longer before accuracy degrades, and spend less time cleaning when you're done.
Little of the drawbacks of moly: Supposedly doesn't really build up in the barrel, so you don't have to condition a barrel to just hBN bullets, and you can interchange shooting with uncoated bullets without thorough cleaning in between. Also since it's not a disulfide there's no risk of it forming acids that might attack the barrel if not thoroughly removed.
Little of the drawbacks of moly: Supposedly doesn't really build up in the barrel, so you don't have to condition a barrel to just hBN bullets, and you can interchange shooting with uncoated bullets without thorough cleaning in between. Also since it's not a disulfide there's no risk of it forming acids that might attack the barrel if not thoroughly removed.
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