Poly Rifling and hard cast lead?

[Peter M. Eick]

I know I should not run lead in Poly rifling but I was curious if I could use hard cast lead in poly rifling?

I picked up (won) an EAA Witness Hunter 10mm that has poly rifling. I was planning on using mostly lead in it in terms of 200 grn full power (1200 fps) hunting loads in it. Obviously this makes me rethink things.

Anyone really play with lead and poly rifling and have any advice?

 

[Springfield0612]

This topic has been in dispute many hundreds of times throughout the years. From doing some research I can see the issue comes down to is the bullet fitting in the barrel and allowing for proper obturation. Obturation or sealing not to allow any of the gasses to pass between the bullet and the barrel. If non-obturation occurs you get gas cutting which in turn leads to leading. A lack of obturation would happen from using a bullet to small in diameter for your barrel. The rule is to shoot a bullet at 1-2 thousandths bigger than your barrel. In a poly barrel the leading can build up to the point that it can cause catastrophic failure. So for people to say that you CAN'T shoot lead out of them vice you need to have your ducks in a row and know what you’re doing. I would check in at the castboolits website and read and learn there for anything lead and shooting. But step one: slug your barrel. Step two: do the math for the pressure you will be shooting your 200 gr bullet at and calculate the needed BHN hardness of your alloy. Step three: using gas checks may allow you to shoot a softer alloy at higher speeds while reducing or eliminating leading in your barrel.

Remember there is a difference between CAN'T and SHOULDN'T. Either way be safe, be smart.

 

[fecmech]

I know I should not run lead in Poly rifling but I was curious if I could use hard cast lead in poly rifling?

That's very similar to a statement that I grew up with(I'm 70), "You can't shoot lead bullets in a .357 magnum". It was BS and so is the poly rifling bit. Any number of people doing it with great success including myself. I put over 3500 cast bullets through my Kahr K9 9mm with a poly barrel. No problems, no leading and good accuracy. Just make sure the bullet is big enough to seal the bore with a good lube. Nothing to it, requires no special incantations or incense burning or sacrifices to the barrel Gods.

 

[Rule3]

There are those who do and those who don't. I figure the gun makers write in their manuals to not use lead in poly rifling for a reason (excess fouling). Kahr and Glock are two.

The debate has gone on forever and will continue to do so.

Don't run with scissors

 

[fecmech]

There are those who do and those who don't. I figure the gun makers write in their manuals to not use lead in poly rifling for a reason (excess fouling). Kahr and Glock are two.

I owned a Kahr and researched Glock manuals a couple years back. Neither mentioned lead at all. Glock did mention NOT shooting reloads. Maybe I missed that or maybe manuals have been updated. Respectfully, could you please point me to a factory manual from Glock of Kahr forbidding the use of lead?

 

[Rule3]

Page 25

http://www.kahr.com/PDF/kahrmanual.pdf

http://us.glock.com/customer-service/faq

Can I use lead bullets?
No, we recommend the use of jacketed ammunition only.

 

[fecmech]

Thanks, the Kahr has been updated I see, mine did not have that recommendation. As you said "The debate has gone on forever and will continue to do so".

 

[Rule3]

As mentioned for any barrel type proper fit is key to eliminate lading, Hardness or softer also. If the bullet does not expand (obturate) the gases go around it and melt the outside and lead the barrel.

So swear they use standard Glock barrels and shoot lead all the time, others buy after market barrels and then no worries.

Of course all manuals say to not use handloads either but that is a warranty issue.

I only have a couple poly rifling and I do not shoot lead in them. I do not need to

My PM9 never saw a lead bullet.

 

[Edarnold]

Interesting coincidence: a quote from the 'Glock Owner's Guide' on the Gun Digest website discusses using lead bullets in the Glock. The author specifically refers to the roughness created by the Tennifer treatment of the bore as part of the problem with excessive leading in original Glock barrels.

Jacketed bullets deal with bore roughness by laying down a smooth layer of metal that covers the imperfections and protects the following projectiles. I've several times had the disappointing experience of cleaning the bright-looking bore of a military surplus rifle, and seeing the bore get darker and darker as the metal fouling came out, revealing the pitted steel beneath. Unfortunately, lead alloys don't have the self-lubricating properties of copper-based jacket alloys. Once leading gets started, it often continues to build up.

Long story shorter, if your polygon rifled barrel doesn't have a treatment that leaves it roughened, assume that it will handle cast bullets the same way as any other barrel. Success will come from the right bullet diameter, the right alloy hardness, and the right lube, combined with an appropriate powder charge.

 

[fecmech]

My PM9 never saw a lead bullet.

That's interesting, my K9 shot over 3500 lead bullets before it saw a jacketed one. A friend gave me a partial box of XTP's that I shot up shortly before I sold the gun. As you mentioned fit is important along with a good lube and powder appropriate to the desired velocity. An experienced cast bullet shooter and caster IMO would have few if any problems using cast in poly barrels. A fellow buying some hard cast commercially lubed .356 dia. bullets could be another story entirely. The devil is always in the details.

 

[Archie]

Interesting...

The Kahr manual contradicts itself:
Page 21: "The use of reloaded ammunition will void the warranty..."
Page 25: "We do not recommend lead bullets in Kahr pistols with polygonal rifling."

I'm not aware of factory loaded 9x19 ammunition with lead bullets. Then again, I don't buy much factory loaded ammunition.

The Glock manual that came with my issue Glock 17 forbade 'reloads' as voiding the warranty as well. It had NO mention of lead bullets at all. Then again, it listed Glock pistols as having 'polygonal rifling', except for the .45 ACP version, which had 'octagonal' rifling. As if an octagon is not a polygon. Nor are Glock pistol barrels 'polygonal' in rifling cross section. More of a washed out lands and grooves look to me.

So here's my bottom line on the subject: I've shot S&W pistols and revolvers, Colt pistols and revolvers, Ruger pistols and revolvers and Browning pistols for a number of years with lead bullet reloads. None of them give me any problem.

A gun that will not handle lead bullets is a defective design from the beginning.

 

[LiveLife]

I do not consider Glock rifling a "true" polygonal rifling rather round bore with "rounded" rifling.

Here's comparison picture of conventional square cut "land/groove" rifling vs true "polygonal" rifling - http://en.wikipedia.org/wiki/Polygonal_rifling


This is conventional square cut rifling

This is Glock barrel showing rounded rifling.
Do you see a polygon (in this case, a hexagon)? I don't. I see a round bore with six rounded rifling.

As to OP, shooting lead bullets in "true" polygonal barrels can result in leading issues as tight bullet to barrel fit cannot be made as well as round barrel due to polygonal voids.

 

[Rule3]

Glock actually calls their rifling hexagonal

 

[ljnowell]

I have been shooting lead out of my G21 stock barrel since I bought it. Works like a champ. Never had any leading issues. My two favorite bullets are the Missouri Bullet 230gr LRN(Softball) and the Missouri Bullet 200gr RNFP(IDP#4-XD). They both shoot beautifully and produce no leading with my loads.

I have loads for both bullets using AA#2, AA#5, and 700x.

 

[sexybeast]

35,000 rounds of hard cast lead through my stock glock barrels. Someone mentioned early barrels being different, I have an early [gen 2] g17 bought new in 1989 and I have shot 20,000 lead rounds through it at least!
I agree with much above about the round being the correct size and not too powerful of a load. Lead does have tighter parameters and you can't push them as hard because of the softness. I rarely push 9mm 125's past 1050fps.
After reading about the lead/polygonol rifeling for so long now I have come to the conclusion that there are those that "read forums" more than they shoot, seem to regurgitate what they read without any first hand knowledge. And there are those that just hate any gun other than a 1911!
Someone at the range once loaded up some 9mm lead bullets in his .357 because they were "almost" the same size. He ran them hot and blew up his gun with all of the leading! If he blew up a glock everyone would have blamed the gun!

 

[ArchAngelCD]

One of the few semi-autos I own is a Glock 19 and after the first 100 rounds of Federal 115gr FMJ ammo that was put through it I have shot nothing but 124gr Hard Cast reloads. I'm thick headed and gave it a try. If the barrel leaded up or the ammo was completely inaccurate I would have bought an aftermarket barrel but the stock barrel shoots just fine. (to my surprise after all the bad press)

 

[Jesse Heywood]

I'm not aware of factory loaded 9x19 ammunition with lead bullets. Then again, I don't buy much factory loaded ammunition.

S&B makes a 119 gr. LRN. I know because I used to buy factory ammo.

 

[kelbro]

My HKs have fired 10s of thousands of my cast bullets without a problem.

 

[kostner]

Have shot many thousands of my 200 grain 45 acp casts bullet through my Glock-36 and never have a problem with leading using Lee Alox for lube.

 

[Dr.Zubrato]

Another vote for "i shoot lead in my glock 19 stock bbl".
So long as you know what you're doing with lead you're OK, jack