Polygonal Barrels and Lead

[Dieppe42]

I have a question if lead building up in polygonal bores is really a thing?

I have shot more than 1k Bear Creek, and Midway hard cast 45's in my USP and have never had any lead in the barrel (like zero). I know HK and Glock warn against it, but is this really a bugaboo, or are these bullets too hard to wipe lead into the barrel?

Guidance appreciated.

[Scotty]

I shot some Lasercast bullets through my USP45 a long time ago. You can see the lead smears in the barrel. On regular rifled barrel, there was still a little leading but nowhere as much as the polygonal barrel.

[NapalmCheese]

I have a question if lead building up in polygonal bores is really a thing?

I have shot more than 1k Black Bear, and Midway hard cast 45's in my USP and have never had any lead in the barrel (like zero). I know HK and Glock warn against it, but is this really a bugaboo, or are these bullets too hard to wipe lead into the barrel?

Guidance appreciated.

The problem is multifaceted.

Any lead bullet can lead up any bore. From my understanding however, if a bore with polygonal rifling starts to lead it increases pressure much more quickly than a bore with standard rifling. It is for that reason HK and Glock say not to use lead bullets.

I have some shot lead bullets that left obvious leading in a polygonal bore after 3 rounds.

[Steelplate45]

And simply follow

with 3 FMJ and the lead is gone...

[OCEquestrian]

with 3 FMJ and the lead is gone...

As long as there isnt too much lead and the gun blows up on the first FMJ round..

[bruce381]

"Any lead bullet can lead up any bore. From my understanding however, if a bore with polygonal rifling starts to lead it increases pressure much more quickly than a bore with standard rifling. It is for that reason HK and Glock say not to use lead bullets."

This is true BUT I run medium hard cast lead in my Glock 21 @ 1 thousand over bore size .4525 and a good lube. Have gone about 700-1000 rounds with only a slight streak of leading in barrel if that. Also a poly angle barrel seals better with less blow bye than a cut barrel and should have higher velocity.

[huckberry668]

I've shot and seen people shot many thousands of lead rounds thru polygonal pistol barrels. It's not an issue long as you're mindful of the leading situations and uphold a regular and proper cleaning regiment.

Sent from my SM-G930V using Tapatalk

[robert101]

I've shot and will continue to shoot lead bullets in my Glock barrels. I check all of my barrels for traces of lead and copper after each range visit. Yes, some barrels will keep more deposits than others. This is an issue complicated by caliber, load, bullet diameter, powder, velocity, etc. I know my bullet components, and my equipment, so for me it is not and issue.

[jsanch03]

[jsanch03]

Check out the folks at castboolits.com there are several threads that cover the lead bullets in Glock barrel debates. Once I did some reading and minor tweaking for reloading 9mm I was on track and saved myself from buying an aftermarket barrel.

[Cowboy T]

I've shot plenty of my own cast bullets through a Glock 21. No leading problems. In my experience, the problems are A.) using the wrong hardness, and B.) improper bullet lubing. For anything involving handguns, generally the softer, the better (exception: monsters like .454 Casull and such). In the Glock 21, I use BHN 10.5 and liberal amounts of liquid Alox. Sure, there's a little smoke, but it shoots great.

Did the same thing with 9mm, unsized (drop to 0.3565" to 0.3570") with a Glock 17. Again, BHN 10.5, liberal coat of liquid Alox. No leading problems, and it shot great.

That's my formula. There are others as well.

[RegionRat]

If you are not aware of what leading looks like, or how fast it can cause serious damage, best to stop and get with someone who knows how to demonstrate before you attempt it.

The Glock polygonal barrel warnings are serious and it can be confusing to hear that others can run cast lead. They warn you because it can cause a serious condition which can lead to damage and injury very quickly.

It is possible to run cast lead in Glock barrels but it takes specific knowledge or else just stay away from it.

The Castboolits forum is the place to go get educated if you want to pursue this, but I would advise you find a mentor who can demonstrate both the wrong way and the right way so you know the difference and how fast things can go bad.

[Clemje]

If you are not aware of what leading looks like, or how fast it can cause serious damage, best to stop and get with someone who knows how to demonstrate before you attempt it.

The Glock polygonal barrel warnings are serious and it can be confusing to hear that others can run cast lead. They warn you because it can cause a serious condition which can lead to damage and injury very quickly.

It is possible to run cast lead in Glock barrels but it takes specific knowledge or else just stay away from it.

The Castboolits forum is the place to go get educated if you want to pursue this, but I would advise you find a mentor who can demonstrate both the wrong way and the right way so you know the difference and how fast things can go bad.

THIS!

I've shot a whole bunch of cast boolits through Glocks over the years. It takes a careful combination of boolit size, alloy composition/hardness, boolit speed, lube/coating and a watchful eye for warning signs to be successful at doing it but it's entirely possible.

FWIW, powder coating eliminates 90% of cast bullet problems as far as lead fouling goes. Appropriately shaped for an auto loader and properly sized, I haven't found a powder coated cast bullet that wouldn't shoot completely trouble free in a Glock yet.

[TomMcC]

I think it depends a lot on the particular bullet and gun combo. I shoot poly coated lead through a G34 with zero leading. Back in the day though, I think I came right close to grenading a G23 with some Bear Creek molys. Some, maybe most poly barrels will be just fine with some sort of lead bullet, but others...watch out. Test your particular combo carefully and if you don't see any probs with leading, press on.

[ar15barrels]

I have a question if lead building up in polygonal bores is really a thing?

I have shot more than 1k Black Bear, and Midway hard cast 45's in my USP and have never had any lead in the barrel (like zero).
I know HK and Glock warn against it, but is this really a bugaboo, or are these bullets too hard to wipe lead into the barrel?

Guidance appreciated.

If you are using a hard enough bullet for the velocity/pressure and it is properly sealing the bore, leading should not be a problem.
If the bullet is not a tight enough fit, gas can leak past the bullet and that will melt some lead and start the leading.
If the alloy is too soft for the pressure, gas can leak by and start leading.
If velocity is too high for the alloy hardness, that can start the leading.
Stay below those 3 thresholds and your experiences with cast bullets should all be positive.