HBN, not for me!

[T-shooter]

My question is - if a slurry of HBN in 90% isopropyl alcohol used on a bore mop or patch will adequately coat the interior of a barrel then wouldn't it follow that cleaned bullets sloshed around in the same mixture and left to dry would be uniformly coated as well? Folks make slurries of resin in alcohol to coat rifle barrels before removing them so if HBN is miscible in alcohol then this would be a far more efficient way to apply this coating.

T-shooter,

Hopefully you don't plan the fire the HBN coated cases. If this stuff has the kind of lubricity people say it has, then the case would not seal against the chamber and this would not be a good thing.
Also, looking at your excellent closeups of seated and pulled bullets, I would recommend a thorough review of all the components used for neck sizing. All things being equal, it seems to me that you simply have way to much neck tension - despite what you think it might be. Check everything. If you have to put undo force on the press handle to seat and pull bullets it has to be trying to cram to big of a bullet in to small of a hole.



Is that a dremel tool bit? Looks like it would do a really good job of cleaning up a chamfer if used by hand like you mentioned. Where can I get me one?

Ken

If you get a mounted tool for the case necks, be sure it's aluminum oxide. Don't use any regular grinding stone because you'll get loose grit at potentially could find it's way through your barrel.

The necks I used were turned and expanded no more than .002" on the outside with new brass that had been annealed. I'll try loading a couple after running the K&M expander through it which make it less than .001". I won't use the coated case, just did one to see if I could impact coat the inside of the neck.

This is how we learn. Experimentation. Glad I didn't load 100 rounds near maximum pressures using the method that 50 lb's force on the press handle wouldn't pull. Earlier, I had problems with "cold welding" for lack of a better term. I broke down 100 loads to check the powder charges (after getting my FX-300i scale). Most pulled easily (had less than .001" fit) with a collet puller, a few felt tighter, and about 6-7 were stuck. The same as the worst of the HBN coated ones) I had to smack the press handle to break them loose. And these were all loaded and stored the same way and at the same time. Why some stuck and some didn't, I have no idea, but that's when I started using Imperial dry lube. I have some new cases with bullets seated bare and using various coatings that I'm leaving for at least 6 months. I use Unique as a case lube and inside the necks it works great. I took one and lightly heated the case neck with a torch, way less than annealing temperatures. It couldn't be pulled out with my RCBS collet puller. That could potentially happen if a round sat in a hot chamber for a while. The results wouldn't be pretty!

 

[wedgy]

http://www.longrangeonly.com/instru...ron-nitride-bullets-rife-bore-jeff-brozovich/

 

[Willie]

Very good video. Very similar to the info I gleaned from David Tubbs when I first started using HBN. Different tumbling set up, but I know several people that use the rotating tumblers and get good results. They say a picture is worth a thousand words, but a video is better ,to show how easy it really is. I don't have any data to back it up, but I prefer Tubb's kit. It has two sizes of HBN, that he claims gives a better finish.

Forgot to mention that your first cold barrel shot will be very tight to group.

 

[Uthink Uknow]

You're overthinking this reloading game.
Don't use the expander ball. When you fire a round, 50,000 pounds of pressure expand the neck to chamber dimensions. The expander ball is a step you don't need. All you need to do now is size the neck with a neck sizing die. Your necks look, well, um, wrecked.
Take them to the nearest chiropractor.

 

[T-shooter]

One more test. I de-carboned a fired Lapua case and lightly polished it with 2,000 grit sandpaper. It's smooth, clean, and no burrs or loose particles of brass. I seated and pulled a new bullet 10 times in a dry clean case neck. The blur at the top is a piece of fuzz. The interference fit after 10 seatings was .0017" measured with a micrometer in the same spot on the neck.

This is the bullet after 10 seatings in the same case compared to a new one. The dings must be from tumbling. There is plenty of chamfer and it's blended in with no burrs or rough edges.

I took the same bullet, cleaned it, and tumbled it in HBN for 4-1/2 hours. Lightly wiped off the loose powder and seated it in the same case which was untouched except wiping out the neck again with alcohol. The bullet and neck were 100% spotless. It took 48 lbs of force on the press handle to pull it back out and it has the same grooves/scratches as the others. (2 views)

So I wiped off the bullet to remove any loose particles and recleaned the case neck. Then coated it inside with Imperial dry lube. It still stuck but only took 27 lbs force to pull it. Still about double of a bare bullet and case.

 

[Willie]

Something to remember about hBN is this: Much like coolant and oil, it prefers to be in it's natural state. Neither heat, nor cold isn't necessary.

Maybe so, but it's the heat of firing and the heat of friction that allows it to bond to barrel metal and do its thing.

 

[Willie]

T, do you have pin gauges to check your case I.D. If not, do you have a .002" under caliber expander mandrel to set your neck I.D.? How many bullets did you coat for 4 hrs? Any pics of coating results. I feel like you must have much more neck tension than you think.

 

[Shane Roya]

Microlubrol Hexagonal Boron Nitride 98% pure? Something in the 2% could be causing the bullet to cold weld to the brass. I have the same brand of HBN but do not seem to have the same issue. Lot to lot could be enough of a difference.
I have always noticed an ammonia odor when first opening the jar from the vibrator, but I have never loaded a bullet immediately after removal from the process. It has always been at least 24 hrs after coating that I have loaded.
Has always been the question with any product manufactured, it is not the pure part we should be concerned with but what makes up the impure part?

 

[rain164845]

I had the same results years ago that caused me to stop using it.
I noticed increased force needed to seat bullets. Then I tried the alcohol slurry as a lubricant on the cocking ramp on my Savage bolt. Then I tried it as a dry chain lube for my bicycle.
The results were poor in all applications and I haven't used it since. It seemed to act as a friction enhancer rather than lubricant in all cases.

 

[Uthink Uknow]

What are you using to trim to length? The end of the case looks as though it's chewed off by a fivetoothed, I better not go there. It looks as though you used a dull file.

 

[T-shooter]

T, do you have pin gauges to check your case I.D. If not, do you have a .002" under caliber expander mandrel to set your neck I.D.? How many bullets did you coat for 4 hrs? Any pics of coating results. I feel like you must have much more neck tension than you think.

I have a K&M expander which measures .3085". With springback, this usually provides slightly less than .001" fit. I had a turned neck on this case and measured the exact same spot. The difference between having the case empty and a bullet seated was .0017" This time I only coated 1 bullet. It had a nice frosty surface and I wiped all loose particles off before seating it. The same bullet, uncoated, was seated into the same case 10 times with no damage. The case was not resize, just re-cleaned the neck incase there were anything on the surface from the seating process. Also, the expander ball on my Forster resizing die measures .3070".

 

[T-shooter]

Microlubrol Hexagonal Boron Nitride 98% pure? Something in the 2% could be causing the bullet to cold weld to the brass. I have the same brand of HBN but do not seem to have the same issue. Lot to lot could be enough of a difference.
I have always noticed an ammonia odor when first opening the jar from the vibrator, but I have never loaded a bullet immediately after removal from the process. It has always been at least 24 hrs after coating that I have loaded.
Has always been the question with any product manufactured, it is not the pure part we should be concerned with but what makes up the impure part?

The jar says >98%. There is no smell to the HBN and no trace of ammonia odor at any time.

 

[T-shooter]

What are you using to trim to length? The end of the case looks as though it's chewed off by a fivetoothed, I better not go there. It looks as though you used a dull file.

Do you mean a hammer and chisel isn't good enough? I use a Lee trimmer. I think the neck edges are beat up from tumbling with other cases. It's not during trimming. I need to see if that's the case next time.

 

[T-shooter]

I had the same results years ago that caused me to stop using it.
I noticed increased force needed to seat bullets. Then I tried the alcohol slurry as a lubricant on the cocking ramp on my Savage bolt. Then I tried it as a dry chain lube for my bicycle.
The results were poor in all applications and I haven't used it since. It seemed to act as a friction enhancer rather than lubricant in all cases.

I have the same results. There is nothing else to try. Even with a fully carboned neck, it released easier but still shows signs of scratching. I can feel a substantial increase in pressure seating the bullet but it's when the direction is reversed that they lock up. They don't release gradually like something that is lubed. More like glass breaking. I may try seating one completely through the neck in one direction and then opening the case up to get it out. I'm starting to get a pile of junk cases and bullets!

 

[T-shooter]

I'm done! I admit defeat. Nothing else to try. I probably have $40+ in HBN and the trashed bullets and cases. As a last test I took a new annealed Hornady case, lightly sanded the inside of the neck with 2000 grit sandpaper, no burrs, no loose particles, a generous chamber blended in, cleaned it again, and seated a bullet that had tumbled in HBN for 1-1/2 hours. I didn't wipe it down this time, just blew off any loose particles. After seating it (.0016" expansion on the neck) I pushed it completely into the case with the seating stem of another die. Then expanded the case mouth enough it dropped back out. Here is what it looks like only being pressed in one direction. Still got scratches over the whole bearing surface all the way around. It seems worse when the direction is reversed and the bullet sticks. I contacted Microlubrol for their opinion. I'll post it when I hear back from them.

It looks like the spacing of the scratches correspond to the interior surface of the case necks. Both the Hornady and Lapua cases are a series of about 20 semi-flat surfaces which make higher and lower pressure areas around the interior circumference. Look at the closeup of the case mouth. Even completely sanding and polishing the neck interior, I could still see them after seating scuffed the surface. Just the way cases are formed I guess.

I may try some in a 9mm pistol where I can see all of the barrel for any wear or damage. I'll sleep easier knowing I never fired any of these in my rifle. Good luck to everyone that had success with HBN!

 

[Shane Roya]

The jar says >98%. There is no smell to the HBN and no trace of ammonia odor at any time.

The odor is when you take the coated bullets out of the vibrator and first open the canister you have the bullets and HBN in. There is no odor from the jar of HBN.

 

[T-shooter]

The odor is when you take the coated bullets out of the vibrator and first open the canister you have the bullets and HBN in. There is no odor from the jar of HBN.

Just shook up the bottle it was in and there is an ammonia smell. Never noticed before. Wonder why? The HBN powder doesn't smell like that. Ammonia and brass don't play well together. It makes brass brittle.

 

[Willie]

T, I'm not in your reloading room, not following your step by step methods, so I can't really see what's happening. All I know is that something is wrong in your cycle, somewhere. I only know that your effort bears no relationship to my experience with HBN.

Go back to bare bullets and shoot up a storm.

 

[Macropod]

One gentleman I know mixes a few grains of HBN with a pound of powder. I'm not that enthralled with idea as it becomes a sand blasting medium. Actually I believe certain grades of BN are used for that very purpose.

 

[muleystalker]

Giving it a try now. Tumbling a few more new bullets and a fired resized Lapua case which is decarboned down to bare metal. I'll let them tumble several hours. and test again tomorrow morning.

Leave the carbon in the necks.