Rifle Barrel break-in using hBN

[n4ue]

Hi. I didn't find any threads on this subject.....hBN
Preface:
I have a number of new Savage rifles in the safe. Most of them have never fired a bullet that I did not coat with hBN, (hex Boron Nitrate) and also the bore of the rifle. I have been reloading for many years and have tried all types of bullet coatings. First Moly, then Moly with wax. Next WS2 (Tungsten Disulphide, which is supposed to have the lowest coefficient of friction of anything), and lastly the hBN. I really like the hBN because it is very clean (looks like powdered sugar) the others are really messy and because of the particle size, will get in the pores of your skin, if you're not careful.... All these coatings are applied by 'impact plating'. which is super easy. The plating is only one molecule thick, because hBN won't stick to itself.
I just bought a very nice (new) McGowan SS rifle bbl. I asked them what they thought about bullet/bore coatings and they replied they didn't know anything about hBN. They stated that the bbl should be 'broken in' before using coated bullets.
I DO understand a new (especially a 'cut' bbl) will have a lot of very small burrs, etc. However, is my reasoning flawed, thinking the bore / bullet coatings will ease this? I would 'assume' the hBN would allow the bbl to get smoother much more quickly....due to much less friction.
In fact, my Oheler 35P shows a consistent 50 fps LESS with the coated bullets. Easy to get the velocity back, with a powder increase, but I'll take the reduced pressure any day.
After a range session, I wipe the bore with Kroil, dry and re-coat with hBN. I have yet to see any Cu tracks in any bbl....

BTW, all these Savage center fire rifles (with tuned triggers) will shoot near one hole groups from shot one. Yes, they do have target scopes and a good shooting bench......
I haven't found many folks that would even be willing to try (or discuss) this process.
If David Tubb uses hBN, it can't be all bad.......

Expert opinions needed!
thanks,
ron

 

[Chris B.]

Barrel break in is a myth. Just shoot the gun as you normally would. This has been discussed at length at AR15.com.

 

[dinkydau]

Barrel breakin is a very opinionated subject with no real proof either way other than what people think or feel is correct. You are correct that it would make more of a difference with a cut barrel but with most barrels being button pulled these days l dont think its that important. I feel this is somthing that was started by benchrest shooters with cut rifle barrels that has become a myth that all barrels must be broke in.l have done it both ways with new barrels and can find no difference in the outcome of how they shoot or ease of cleaning. Its more important not to over heat a barrel(if you cant keep your hand on it its too hot)and do cleanings after a set number of rounds fired. That for me is 25 to 30 rounds as l shoot for groups off a bench but my rifles are not full blown benchrest rifles, more of a heavy varmint rifle. The rattle battle rifles come with chrome bores anymore to combat the heat and fouling of firing large amounts of ammo.
l played with moly coating years ago but gave up on it because of like you said the mess and l could find no real improvement in reduction of jacket fouling. You are correct these coatings reduce friction but also think they increase the time it takes for a barrel to shoot in. Yes Savage barrels are good shooters but they are some of the roughest looking barrels out there. Ive got a Shilen 1-8 twist 223 SS barrel on a Savage action and its smooth as glass but really doesn't shoot better than the barrel that came on the rifle that was rough as a rocky road, but does clean way better.One well known barrel manufacturer said he recommends breaking in barrels because thats what customers want to hear, he didnt think it made any difference.
lf breaking in barrel makes you feel good then by all means do it.
JMHO. DD

 

[n4ue]

DD, thank you for the great reply. I did a bunch of 'research' of this subject a while back. I believe 6mmBR had an article that had the recommendations of the bbl makers. As you state, it was all over the place.
I understand about the heat. Since we here in the Sunshine State, have no PD towns or even any Groundhogs, I shoot slow. Since I usually develop 'long' hand loads, I don't even bother using the factory magazines. I make a follower to put in the mag, and single feed the rifles. That in itself, slows down the shooting rate. ha ha
Besides, I usually walk to the target after every 5 shots or so. I enjoy being outside and like the exercise. We have a private range.
You should try hBN, it's great stuff. I mix it with different carriers. For the bore, I use 91% Alcohol. But I have used Kroil, MMO, etc.
thanks again

ron

 

[demarpaint]

Do you coat your bullets with it?

Can you use it in a barrel after MoS2 or WS2?

I was sent a large sample of it, [a lifetimes worth] and was considering trying it for the reasons you mentioned above.

 

[Astro14]

In the manual for both of the rifles that I bought recently (a DPMS LR-308 and an Armalite AR-15), break in consisted of cleaning after every few rounds until 100 rounds were reached.

I followed those directions, running a boresnake with CLP every 5 rounds...did it work? Well, I am still shooting with iron sights, and can't really get a precise accuracy determination because I am the limiting factor...

 

[dinkydau]

When l quit using moly they were just starting to talk about WS2 and lve never read anything about hBN, will have to look into it. Just got use to shooting naked bullets again! Sounds like your a handloader and not just a reloader and your shooting routine is same as mine. Strive for the bughole! Everything else is just shooting.
thanks for the info. DD

 

[The_Eric]

Novice question here...

If you're coating bullets to reduce friction, then why does the chrony show a reduction in muzzle velocity?

 

[dinkydau]

The reason you lose velocity with a coated bullet is because because of less friction the same powder charge compared to a non coated will not produce the same(lower)pressure and that equals less velocity. Not a ballistic expert so dont know the dynamics of it but is stated in many articles on the subject.
DD

 

[demarpaint]

Originally Posted By: dinkydau
The reason you lose velocity with a coated bullet is because because of less friction the same powder charge compared to a non coated will not produce the same(lower)pressure and that equals less velocity. Not a ballistic expert so dont know the dynamics of it but is stated in many articles on the subject.
DD


You nailed it.

 

[edhackett]

OK, so you coat the bullet and loose velocity. You have to add powder to regain your desired velocity. The increased powder charge decreases barrel life and increases recoil. This is desirable?

This question coming from someone with three rifles in his safe that can put 5 in one hole. None shooting coated bullets or "broken in", just quality, off the shelf rifles shooting quality hand loads.

Ed

 

[dinkydau]

Yes you are adding powder to regain the lost velocity but recoil would not increase since you are just bringing the pressure level back up to where it was with the uncoated bullet. Since the pressure level matches what the uncoated bullet was at there should not be any increase in wear on the barrel and if anything should improve because of less friction traveling down the barrel.
The main benefit of using coated bullets is the reduction of jacket fouling and ease of cleaning. This again is something that started with benchrest match shooting for the ease of cleaning between matches and bled over into hunting and varmint rifles.
If your not concerned with the time it takes to properly clean a barrell or if your guns dont foul that bad then its not for you. Coated bullets will not make a rifle anymore accurate that lve ever found. Sounds like you got some real shooters, l wouldnt change a thing! DD

 

[edhackett]

The weight of the powder is used in the calculation of recoil. It is mass being moved down the barrel. The recoil is the result of he total mass of the bullet and powder. Increasing the powder 5 grains increases recoil by the same amount as increasing bullet weight by 5 grains.

I agree that coated bullets likely reduce wear on the rifling, but larger powder charges do accelerate throat erosion.

As you say there may be benefits in certain areas, but as with everything in life, it comes at a cost. There is no free lunch. It's up to you do determine if the cost of the lunch is reasonable.

Ed

 

[dinkydau]

All you say is true but doing a quick comparison on a 223 - 30/06 and 300 win mag in a Speer manual it takes only one or two grains of powder to regain the 20 to 80 fps that the average coated bullet looses. Dont know about your shoulder but mine will never feel the increase in recoil. The extra throat wear from two grains of powder would be very slight but present. Not for everybody for sure. DD

 

[demarpaint]

Delete

 

[n4ue]

All great replies.
As far as the velocity loss, the amount of powder increase to get back to the uncoated bullet velocity, will make the recoil the result of 'ejecta', that is, the combination of the powder's weight plus bullet weight. However, the pressure will still be less due to the reduced friction. Norma did some pressure testing a while back with WS2 coated bullets. I hBN 'impact' plate all my bullets with a homemade tumbler with a timer, so it's very little work.
You can find some excellent info on 6mmBR.com about coating bullets. Also the www has great info on hBN and it's development for lubricating in space and high temp/pressure applications.
I recently did some 'research' concerning 'barrel break in'. This was the opinions of all the big time bbl makers: Lija, Krieger, Hart, etc. Also in this poll were the comments by many world champ benchrest shooters. There was very little agreement! The opinions were 'just shoot it', to 'clean after every shot'. There was even more wide opinions on how to best clean the rifles' bore, and what chemicals are best.

I'm going to just keep doing what works for my rifles.

I currently reload 38 different ctgs, including several wildcats, that I made bbls for. It's all about fun and the challenge.

ron

 

[dinkydau]

N4ue now your talking, looking for the change or tweak to make your handloads preform better.l ordered a small amount of hbn off amazon so the search will continue. Hope it works as good as advertised. Will update after lve had a chance to play with it. Thanks. DD

 

[Sonataman]

I've barreled many a rifle and the first shot out of the new barrel can result in little to no copper all the way to what looks like gold plated lands and grooves.

The one shot and clean method is, in my opinion, pure nonsense. Take that one shot coppered bore and letting the borescope be the judge on when your done, clean it until it's copper free.

Or, shoot a minimum of 20-30 rounds before the first cleaning and the copper comes out much quicker/easier.

The ones that copper more generally take a while to settle down to where they don't. Best barrels I've seen copper little to none from the first shot.

I've never shot coated bullets but I don't see any reason the barrel won't be fine.