Applying boron nitride on bullets

[acloco]

Ok a dumb question. Why coat bullets with boron nitride ? What are the benefits ? Thought molly coating was on its way out ?

The only common link between HBN and moly...is...you coat bullets with them. Other than that, they share nothing in common.

 

[rogn]

Re: Applying boron nitride on bullets/ not doin so well

Tried my hand at treatment last week and washed a batch of SMK 77 gr as well as afist full of new BBs, placed em on paper towels O/N on top of the furnace and precoated he BBs and then added hBN and bullets , gavem abt 1 1/2 hr , checked asaw a slight coating. Added a grain or so more and vibrated for 2 1/2 hr longer. Resulted in a tarnish on thee bullets, a moderate level of coating, and worst of all amild ammonia odor in the bottle. Water must be the culprit, but not entirely sure. Any ideas?

 

[David Bookstaber]

I also just tried tumbling with HCPL-grade hBN and when I opened the bowl after a few hours of tumbling there was a strong ammonia odor. There's a definite haze on the bullets, but they don't feel to my fingers significantly more lubricious than polished copper. What's going wrong?

 

[kelbro]

I just tried this tonight. Got the HBN over a year ago and have been travelling too much to do any experimenting.

Cleaned up some zinc coated steel BBs and some 75gr Hornady BTHP match bullets with acetone. Put the BBs in a vitamin bottle to coat and dropped them in the Lyman tumbler for about 20 mins. Looked good and coated. Added the 100 bullets and ran for 30 mins. Look just like all the sample pictures.

Now I need to load them up. I have read about pre-treating the barrel. Not sure about that. I may try it. Also read that if the barrel is electro-polished that the effects aren't as drastic. These will most likely be shot in a SHilen Stainles Select Match barrel so we will see how it does.

 

[kelbro]

Update... Loaded up a batch and went out to shoot.

The accuracy node definitely moved up. I suppose due to the lower friction creating slightly different harmonics. The node velocity may be the same, didn't take the chrono to verify.

Noticed that I did not see the bolt just start to get sticky until 26.5 gr (H4895) and this previously occurred at 26.1 gr.

Barrel ran cooler.

Boresnake with no brushes left the bore spotless.

I like the stuff.

 

[chevi_guy]

Kelbro
You sure made the process of coating the bullets with HBN seem much simpler.
I have never tried coating my own bullets.
So you coat the bb's with HBN first then put the bullets in and Tumble or Vibrate.
Where can you get HBN and what form is it?
I see above someone said to where respritory protection. You did not mention that.

Thanks for the simplicity.
B Foster

 

[mc223]

There is an individual right here on this forum that is selling HBN.
Try search for HBN

 

[kelbro]

Kelbro
You sure made the process of coating the bullets with HBN seem much simpler.
I have never tried coating my own bullets.
So you coat the bb's with HBN first then put the bullets in and Tumble or Vibrate.
Where can you get HBN and what form is it?
I see above someone said to where respritory protection. You did not mention that.

Thanks for the simplicity.
B Foster

Yes, it was that easy. Since then I have coated another few hundred bullets and this method works great.

I would recommend at least a filter. I noticed a little dust but not enough to worry about.

I am using 70nM sized.

Shot more this weekend and the barrel appears to have no fouling to speak of.

 

[tunered]

We all learn, had you not called him out, we might have not gotten this info, Thanks. ed

 

[zfk55]

My aplogies for not noticing your post, but really it wasn't necessary.
I do have an update. We have a rifle now over the 400 mark haveing shot .30 caliber hBN coated projectiles through a slurry treated bore. The only cleaning is done with a dry swab after every shooting session. No solvents, nothing but a dry swab. Thus far there's no copper fouling.

There is something we began doing last fall on a tip from an associate of the patent holder. We now heat the projectiles during the coating process. We use a Halogen body shop light, but you have to be extremely careful not to postion your heat source so close to the vibrator tumbler as to case the plastic to react! It takes some experimenting, but when ours are done after the three hour session they're almost too hot to handle.

I know that the very great majority do not use heat at all with good results. This is what we do, and the control rifle and borescope prove it out to us, anyway.
If it takes a lot of rounds to show copper residue, then you're doing something right.

You can completely clean the bore with Alcohol and begin again if you need to remove any traces of copper fouling..
zfk55

 

[spclark]

Yeah, when I was running moly I found heat helped things along. Winter's the biggest challenge so I built a "conditioning" chamber out of a 30-gal steel garbage can, an electric baseboard heater thermostat and a hair dryer. Idea is to put my tumbler underneath the contraption with the hair dryer connected to the thermostat to regulate temperature over the run.

Works great once I learned my tumbler manufacturer used some kinda hot glue to bed the tumbler mounting springs... First run had the temp a leetle bit high & the glue melted.

I aim for about 95 - 100° F which seems to work well with the hBN too though I've switched to an RCBS rotary with two peanut butter jars placed inside the tumbler body. The bullets & stainless shot go in the jars with the hBN powder, the tumber bodys have corn media inside as a cushion of sorts. I run the tumbler for about 90 minutes a batch.

 

[zfk55]

For hBN it appears that the heat advantage is that the projectile jacket "opens up" a bit and the penetration is somewhat better. Under a scope our projectiles don't have the slightly mottled appearance I've seen in on-line close-up pictures.

Latigo

 

[spclark]

That's my surmise. All kinds of processes work more effectively at higher-than-room temps. Challenge is in finding out how high is enough.

 

[19zip]

zfk55.
I'm just learning about hBN bullet coating from your and the other members posts. So what is the process you finally settled on? The Thumler's tumbler or the Frankfort vibrator method? Which gives the best coating? Did you stay with adding 3gr. to a batch of 100 - 6mm bullets or go with more or less hBN? Still vibrating / tumbling for 3.5 hrs?
I already had the PB jars and the Dillon vibrator. I'm trying your vibrating method right now.
About the barrel coating. If i understand you correctly you are applying it dry on a new .30 caliber cotton swab. Do you try to heat the barrel's bore some way so the hBN will stick to it better? How has your shooting coated bullets turned out? Sorry about all of the questions, but I got interested in this, reading about your testing and I never saw any follow up after your 02/11/11 post. Thanks for any help

 

[sbrabec]

This is how I understand the process after a few PM's to zfk55.
1. First start by washing new BB's in Dawn soap and dry over night.
2. Fill jar (I use peanut butter jars also) 1/4 full w/ new BB's and add 1.5 grains hBN and tumble for 3 hours.
3. Wash bullets in Dawn soap (I did this at the same time as the BB's) and dry over night
4. Add 50-100 bullets to the BB's, jar should be about 1/2 full (I'm doing 6mm107SMK) and add .5 grains hBN for 50 and about .75 grains hBN for 100 and tumble for 3 hours
5. Remove bullets from jars, separate from BB's and roll back and forth in a terry cloth towel.

I'm using a Frankford tumbler with the jars tightly packed with foam and the bullet coating results look great. I haven't coated the barrel or loaded any bullets yet, winter doesn't want to leave MN yet and I got 100 rounds to fire from last year. Hope this helps.
Scott

 

[zfk55]

19zip, I do a hBN and alcohol slurry. I mix it to the consistency of whole milk. I keep a small jar completely air tight and it lasts on the shelf without evaporation. I apply it with a slightly undersized mop like a .270 in the 30 caliber bore. I fire one round within an hour or so.

You've about got it right, Scott. The projectile should not appear mottled, but a solid, darker color and they'll feel very slick when handling them. If your coated projectiles are leaving any trace of copper in the bore then there's a part of your process not working.

Latigo

 

[Steve Blair]

Update... Loaded up a batch and went out to shoot.

The accuracy node definitely moved up. I suppose due to the lower friction creating slightly different harmonics. The node velocity may be the same, didn't take the chrono to verify.

Noticed that I did not see the bolt just start to get sticky until 26.5 gr (H4895) and this previously occurred at 26.1 gr.

Barrel ran cooler.

Boresnake with no brushes left the bore spotless.

I like the stuff.

If you shoot over a chronograph, you will find that your velocity was reduced. A slightly larger powder charge is necessary to return to the previous velocity.