Powder Coating Bullets To Increase Diameter And Or To Protect Plating.

[arakboss]

The most common benefit of powder coated cast bullets is reduced leading. I am interested in other benefits that powder coating bullets may provide.

I bought a bunch of light 308cal jacketed bullets and plan on trying some in 7.62x39 barrels. The standard 7.62x39 bullets are usually .310/.311 in diameter. Powder coating the 308 jacketed bullets would increase the diameter of the bullet and may provide increased accuracy.

This could also work on .355 jacketed, plated or cast bullets for use in 38cal pistol/rifle or 35cal rifle cartridges.

An extreme test would be to try powder coating some .257 jacketed bullets for use in 264 diameter cartridges. This would require a coating thickness of about 4mils which would be very easy to do. The big question would be, will the powder coating engrave in the rifling and make up the thickness of a very undersized bullet? Also will the thick coat of powder hold back the pressure behind the bullet?

People are rocketing powder coated cast bullets at higher speeds than plated bullets will withstand. I think by powder coating a plated bullet, it might be able to withstand speeds equal to or greater than a powder coated cast bullet.

What types of tests would you like to see to demonstrate whether these ideas are valid or not? Is there somebody with a good chronograph that would help me test out the various coated bullet types at the range?

Edit: Another benefit of powder coating jacketed and plated bullets might be reduced copper fouling?

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[arakboss]

I coated up a few Norma 8mm (.318) bullets and was able to easily add 2.5mils of powder to the bullet. This increased the diameter to .323. This was a normal coat of powder and I could have applied it heavier. I also powdered some copper gas checks and in the photo you can see the one I bent in vise after coating was cured. The coating developed a small crack in the middle outside of the bend but the coating did not flake off.

I think I will lube these bullets and run them through a .314 Lee sizer die. If the coating remains intact, that will give me confidence that this process could work.

 

[Saladfarmer]

I've pondered the same . I have loaded 110 gr 308 speer hollow points in 762 x 39 with no coating and they were Very accurate, most accurate projectile I've loaded actually. Yet cast and coated 145 gr sized to .311 tumbled to keyhole from the same rifle (16" 1 in 9.5 twist green mountain barrel)

 

[arakboss]

I've pondered the same . I have loaded 110 gr 308 speer hollow points in 762 x 39 with no coating and they were Very accurate, most accurate projectile I've loaded actually. Yet cast and coated 145 gr sized to .311 tumbled to keyhole from the same rifle (16" 1 in 9.5 twist green mountain barrel)

That's good news on the 308 jacketed bullet success. I wonder what's happening with the cast bullet?

 

[arakboss]

I ran an 8mm powder coated jacketed bullet through a .314 Lee Sizer die (twice) and it dropped down to .315 diameter. I lubed it with RCBS case lube first and it didn't take a huge amount of effort to push it through. Before I ran the powder coated jacketed bullet through, I ran some 8mm cast (uncoated) bullets through the .314 sizer die. I used the same lube and they ran through the die with not much effort. The diameter on the cast bullets went down to .314

Both bullets grew a little in length, which was expected. I definitely feel that a minimum of .010 is very doable for each sizing step and with cast bullets. With powder coated cast bullets you might be able to go over .010 in each step. I am going to powder coat a few of the 8mm cast bullets and try to run them through the a 309 sizer die.

see post #7 for before and after pics.

 

[Saladfarmer]

Me too. I have a bunch I cast and have resized to 308 and I haven't loaded them up to test yet. My Theory is too much contact. This is based on an experience I had with a barrel I bought a couple years ago that ended up having insufficient riffling straight from the manufacturer. They replaced it promptly and happily, so no need to mention said manufacturers name.

OR I pushed them too hard and too much contact, But I think this was less likely since I was starting low. The bolt cycled at least. With out a chrono, theoretically they should have been in the 2000 to 2200 range at most. From what research I've done coated can be pushed up to 2500fps

 

[arakboss]

 

[arakboss]

Me too. I have a bunch I cast and have resized to 308 and I haven't loaded them up to test yet. My Theory is too much contact. This is based on an experience I had with a barrel I bought a couple years ago that ended up having insufficient riffling straight from the manufacturer. They replaced it promptly and happily, so no need to mention said manufacturers name.

OR I pushed them too hard and too much contact, But I think this was less likely since I was starting low. The bolt cycled at least. With out a chrono, theoretically they should have been in the 2000 to 2200 range at most. From what research I've done coated can be pushed up to 2500fps

What is the profile of the cast bullet?

 

[Saladfarmer]

spitzer

312-145 Elvis

arsenalmolds.com

 

[gmerkt]

You come up with some thought provoking ideas.

I'm thinking this is an updated version of a paper patched bullet. A gilding material jacket is less porous than cast lead. So perhaps adhesion of the coating might present issues. Which might be offset by roughing the outer surface of the jacketed bullet some.

 

[arakboss]

You come up with some thought provoking ideas.

I'm thinking this is an updated version of a paper patched bullet. A gilding material jacket is less porous than cast lead. So perhaps adhesion of the coating might present issues. Which might be offset by roughing the outer surface of the jacketed bullet some.

Ideally I would like to fire a powder coated jacketed bullet into water so I could recover the bullet. I agree that abrading the surface would aid in adhesion.

 

[arakboss]

I am coming back to this idea of make a smaller diameter bullet useable in a larger bore by powder coating them. The latest candidate I have in mind is .257 bullets to be used in 6.5 bores. The lands on a 6.5 bore are generally .256 so an uncoated .257 bullet will probably still not drop free in a 6.5 Grendel barrel. My suggestion is to double coat the .257 bullets and see if they will fly straight in 6.5 Grendel loads. I am still not sure if the powder coat will have suffcient stregth to engage the rifling but it's possible? I am going to double coat a few .257 bullets and see what kind of film build I can get.

 

[ma96782]

I'm wondering......
At what velocity do you expect to use these "coated rifle bullets"?
Are you planning to launch these from a semi-auto platform? Bolt action? Or lever or slide/pump action?
And, what will it's actual purpose be for.....hunting game, hunting/eliminating varmints and pests, target hole punching or whatever?

Aloha, Mark

PS......if you haven't already.....you might want to swing by during a "cast bullet match".

 

[arakboss]

I'm wondering......
At what velocity do you expect to use these "coated rifle bullets"?
Are you planning to launch these from a semi-auto platform? Bolt action? Or lever or slide/pump action?
And, what will it's actual purpose be for.....hunting game, hunting varmints, target hole punching or whatever?

Aloha, Mark

The test barrel for these .257 bullets will be a cheapo Bear Creek Arsenal 6.5 Grendal 1:8 twist (AR upper). I am going to coat up some 87gr Speer and 120gr Sierra's. I dropped both bullets into the muzzle of the bear creek barrel and they went in about an inch and stopped. I tried pressing them in further with cleaning rod and there was quite a bit of resistance so I pressed them back out through the muzzle. Even at .257 diameter they are minimally engaging the lands. I will probably load these up with very light gallery type loads. Ideally I would like to recover the bullets so I can inspect the powder coating. Maybe shoot them in to a barrel of water? Not much purpose in this project, I just want to test some new uses for powder coating bullets.

 

[ma96782]

Good luck with your experiments.

Aloha, Mark

 

[arakboss]

I will double coat some bullets and report back with film build this week. I might take a double coated bullet and pound it through the barrel to see how the rifling engraves the powder coat. That could be the end of the project if the powder coat doesn't engrave well and provide the needed resistance.

 

[ma96782]

And then.......is it just me?
OK, Ok, ok.......perhaps?
Well, a shooting experiment sounds like "FUN".
Of course.......YOU be the judge as to how much coating is used.

Aloha, Mark

PS......warning and good luck.

 

[Capn Jack]

I mainly shoot 325gr. GC cast bullets I size to .459 out of an AR 15 Carbine. They're a good all round bullet for hunting and plinking. I use a mixture of bee's wax and graphite. I have powder coated some bullets, but haven't tried them yet.

 

[arakboss]

I wonder how much FMJs obturate and whether a smaller diameter for caliber FMJ will obturate more or less than a standard for caliber diameter FMJ bullet.

I just wonder if I was to fire a .257 diameter FMJ down the .264 bore if the bullet might obturate a thousandth or two as it's going down the barrel? Or will it just stay at .257? Or will it even leave the barrel, maybe it would stick in the lands but let all the gases go by?

Edit: interesting opinion on shooting small caliber projectiles out of larger diameter bore.

Is it safe to shoot bullets that are lower caliber than the gun is made for?

Answer (1 of 20): Safe for who? 7mm-08, as one example, will chamber in a .308 firearm; the cartridge diameter and length to shoulder are identical, the difference is in the shoulder angle and neck/bullet diameter. As such, you can load, chamber and pull the trigger, and pin will strike primer. ...

www.quora.com

 

[arakboss]

These powder coated .257 bullets run in a 6.5 barrel could be considered a poor mans bore rider bullet. Instead of having engraving bands constructed into the bullet, the powder coat may perform that role?