Polygonal rifling

[Rob Pincus]

There's a bunch of guys in Georgia, who work at a place called Glock, Inc. They are specifically of the opinion that you SHOULD NOT shoot lead in your Glocks.

That's good enough for me. I would consider all advice to the contrary to be reckless and irresponsible.

------------------
-Essayons

 

[AC]

I'm a bullet caster. My guns don't lead because the loads I fire use appropriately sized bullets, of appropriate hardness, with appropriate lubrication.

Rob, I have read that firing a jacketed bullet in a leaded bore results in lower pressure for that shot. I cannot prove that but it was stated that the lead actually worked like a lubricant to the jacketed bullet until subsequent rounds shot it out.

I don't understand why a polygonal bore would have any trouble handling a cast bullet of the correct size and alloy for the load. It then should not lead either. There is no reason I can think of that the polygonal rifling would strip the bullet rather than turn it.

I'm sure DDS's H&K isn't stripping or he wouldn't be getting target grade accuracy. As long as the load wasn't leading, he wouldn't even have to clean the barrel, though he would probably want to clean the chamber for functional reliability as bullet lubricant creats soot. I know this will surprise a lot of you guys but there are cast bullet rifle shooters that do not clean their barrels for thousands of shots with no ill effects. It is a similar situation to using a .22 rimfire.

Probably there are specific loading challenges related to the high pressures and maybe gun design flaws, too, that only become apparent at extraordinary pressures.

The people in Georgia are going to give you the CYA answer. It is easier for them to make the blanket statement than coach shooters in the loading specifics. It would be interesting to learn exactly why these guns blow.

 

[Rob Pincus]

Funny, but those guys (and most manufacturers) recommend against reloading in general, as well.

Some of that is CYA, but much of it is simply because Glocks are designed to work with combat ammo, not competition ammo. There are great guns out there for plinkers and target shooters, Glock is a defensive/comabt pistol. It was originally designed for 9mm NATO Spec (hot) rounds.. not properly casted lead reloads.

This is a no-tolerance pet peeve of mine, so I will back out of further discussion. Obvisouly some people are comfortable shooting anything through anything... but a Glock is not a Blunderbuss, and I feel it should be used with the type of ammo it was designed for.

------------------
-Essayons

 

[Cheapo]

The first reliable report of Glock kB!s I heard was from a friend (I know this ain't reliable to YOUSE GUYS, but...) who was working at the Gunsight Smithy a few years ago. He was on the line when it happened to another shooter--the story was that the shooter was using .40 S&W commercial reloads and had gone about 700 rounds without cleaning.

Other reports I've read here on TFL indicate that pressures go up on Glock barrels as the leading accumulates.

It appears that the reason for excessive leading starting with only a few rounds (I've personally observed this phenomenon) is the geometry of a small "wrench"-like flat being impressed into the bullet. The "lands" part of these polygon barrels is a flat spot inside the groove-diameter curve. Think of it as being like a 2x10 laid inside a 24-inch sewer pipe...the plank rests on the curve, and creates a smaller diameter region inside the pipe.

Well, those flats in the barrel flatten out the bullet and impart the rotational spin to it. But IMHO (really more of an educated estimation), that combined impression and wrenching action is different enough from a corner cutting into the bullet to impart rotation, that it results in far greater "grinding in" action of the bullet against the barrel.

Just think of what happens to a bolt head when you have only half the flat left and rounded corners. The geometry makes it very easy to booger what's left of that flat.

I do not believe that the bullets really strip in the Glock rifling. Most .40 barrels just aren't that accurate to begin with!

But here's the question: Do H&K barrels quickly lead up too?

Despite leading up quickly, I find that a Glock barrel is very quick to clean when Oregon Trail bullets are used. They do lead less than other lead pills, but I haven't yet tried to find an accurate load with them.

 

[Mikie]

I have read the chat groups on the web for the past year enough to have heard both sides to this issue: complete prohibition of lead in polygonal barrels(Glocks and H&Ks) and guys who have done it successfully and safely for years and thousands of rounds. I can share myexperience. I fired well over 500 rounds(3D Lead SWCs)in combination with FMJs from time to time through my H&K USP40C when it was brand new before I knew it was supposed to be a no-no. With routine cleaning after each session I have had no problem with leading. Checking the barrel reveals little to no leading(it looks glassy smooth). I have since reloaded and fired 500 LRNs each through a Glock 23 and the USP40C and continue to find little to no leading with routine cleaning. The kinds of bullets I have used include: Oregon 155 RNSWC, Bull-X LSWCs and Carrol's LSWCs, and LFPs. I plan on continuing to fire lead as a way to shoot cheap, but largely because of the concerns raised I go to greater lengths to ensure a glassy smooth barrel. If after routine cleaning I see what appears to be a waxy coating that follows the twist I let the barrel soak in lead remover for 15 minutes and then scrub with a brush until it's gone. I believe if you are conscientous in keeping our gun clean you can shoot lead safely in your Glock or H&K. One other caution is don't let more than 100-150 lead rounds go through your gun without cleaning it, thoroughly.

------------------

 

[Tom B]

I have heard alot here about poly barrels except one of the MAIN reasons they are used. They are cheaper to make!

 

[Hiker]

Cheaper or not my Glock 30 w/3.75 inch barrel consistantly chorno's the same or ~20 to 30 fps higher muzzle velocities than my 1991A1 w/5inch barrel w/same ammo. It also cleans easier, cost hundreds less, more accurate....need I go on. I don't think the reason is because it is cheaper.

 

[Tom B]

Please tell me where I can buy a Glock 30 for "hundreds less" than a 1991A1? Yes the poly barrel has more velocity than most other types. No in my experience poly barrels are not more accurate than other types but are less so. They are probably as accurate as a 1991A1 stock barrel but IMO thats not much of a "role model". Yes the ones I have used in the 60 Glocks I have owned tend to last longer. IMO the only problem with my P7M8 is its polygonal barrel. I feel the weapon would be much more accurate with L&G riflings. Sorry I am Not a Poly barrel fan and again I say they are used by Glock,H&K,etc... because they are cheaper (maybe a better term would be) less expensive to make.

 

[Hiker]

I guess what I should have said is "hundreds less than what you have to pay to have a smith do his magic to make it shoot right." I don't know I payed $450 for a G30 which has the hex rifiling and have had to do nothing to it and it shoots ~2 inch groups (most of the time less) off a rest @ 25 yards right out of the box....and has never FTF. My expereience is mostly with 1911's and I like them a lot but if you can tell me where I can buy a 1991A1 that can shoot that well (out of the box) and maintain the same muzzle FPS and still feed various ammo for $450 let me know Tom B!

Also please tell me of your vast experience with some 60 Glocks! This is my first Glock pistol but not my first polygonal barreled pistol. I have a P7M8 also, never felt the need to do any real accuracy testing with it, it was designed for another intended purpose.

I've heard/read/seen (I haven't shot one) the Glock M17 is one of the most accurate pistols around and it has polygonal rifiling.....food for thought.

Hiker

 

[Cheapo]

Hiker:

The G30 is .45 ACP, isn't it? I'd be most surprised if your accuracy report was for a .40 S&W...

To all--I forgot to specify that my (rumor to you) Glock kB! report involved @ 700 rounds of commercial reloaded LEAD BULLET ammo.

It seems that G17s kB! the least, especially with jacketed, but I've heard believable reports of even that happening. But as we get more HK USPs out here, if polygon rifling were the real problem, I'd expect to start hearing more reports involving those pistols...

Cheapo

 

[Tom B]

Hiker-What would like to know about my experience about the 60 Glocks I have owned? The G30 was the most accurate out of box. I presently have the G19,G22,and G23. The first thing I did was replace the factory barrel. The G19 and G23 now have KKM and the G22 has BarSto. The G17 IMO is not very accurate. I have owned 2 of them one of which was so inaccurate I traded it the day after I got it. My P7M8 is not as accurate as my Sig 228 due to its poly barrel(IMO) however i have only fired 300 rds thru it. The first Glock I owned was the G19 when they first came out and would eject the brass in your head every time. I have owned 3 other G19s since and I like my present one alot. I presently have my G22 for sale (see want ads if interested) and it is accurate because it has a Barsto! I traded my G30 for a Springfield 1911 and ended up spending $800. to make the Springfield as accurate as the Glock 30 was out of box. The 2 guns that have stock barrels which are as accurate as BarStos are Sigs and Browning Hi powers 9mm. I presently have 2each and 1 40cal Hi Power. I enjoy handguns and have been lucky enough to own a few. I will be glad to answer any other questions from my experience in my opinion that I can.

 

[Hiker]

Cheapo,
The G30 is .45acp. I have also shot the G27, G21, and G32. The G27 is a sub-compact .40 S&W cal (3.5 inch barrel) and I borrowed it at my range and ran 100 rds. through it and was suprised at how well it shot. The max range at this particular range is ~33 feet and I had very little problem keeping all rounds in roughly 3 inch group off hand.

As far as KB's I take Rob's position, shoot jacket bullets as factory recommends and keep it clean. Some very experience shooters can shoot and reload lead and be very safe in the more tempermental calibers and barrel types. I only reload and shoot lead in .45 due to it's more forgiving properties. I know the physics of what happens and causes lead related KB's and it can happen in any gun under right circumstance.

Tom B,
I appreciate the info. I have been sort of resistant to new technology in firearms such as the "plastic/tupperware" Glocks, poly rifiling and trick bullets. I've always been very conservative in firearm choices...Colts, Sigs, Berretas and S&W for pistols. It took me sometime to become interested in the Glocks but it has been good experience thus far. I'm sure I'll be requesting advice in the future.

Hiker

 

[walkin' man]

If anyone is still interested in one of the original questions here goes... The HK USP 45(fs) has a twelveagonal or a dozagonal or whatever you call something with twelve sides barrel. The flat spots are of varying size, alternating between wide and narrow, the wide spots being about twice as wide as the narrow spots. I had to go out and buy one , with a stainless slide no less. I loved my USP 40, but I always felt like I was missing something (about .05 inches of bullet diameter).
If it is cheaper to manufacture a polygonal barrel why is it they only come in high end pistols? Does anyone know of any inexpensive pistols with polygonal rifling?
My personal opinion is that I trust HK to put only the finest of materials into their firearms. There have only been two pistols that I trust to work 100% of the time. Both of them were USP's.

------------------
land of the free and the home of the brave......WHETHER THEY LIKE IT OR NOT

 

[Tom B]

Poly barrels come in Glocks and H&K. They don't come in Sigs,Brownings,BarSto,KKM,Accumatch,Wilson,Jarvis,Kimbers,etc...

 

[Tom B]

P.S.- I knew my poly statement would "spark some interest!"

 

[walkin' man]

I know for a fact that the Desert Eagle .50 AE also has a poly barrel.

------------------
land of the free and the home of the brave......WHETHER THEY LIKE IT OR NOT

 

[Tom B]

Desert Eagle. I rest my case!

 

[Hiker]

Kahr pistols use poly rifiling also.
Hiker

 

[BigG]

I agree with AC, a bullet cast with the PROPER alloy should not lead. Unfortunately, most reloaders do not cast, they buy from whoever and have no idea or control over the alloy used. The manufacturers warn against handloaded ammo on almost all guns I'm aware of to limit their liability. Regards

 

[BigG]

I agree with AC, a bullet cast with the PROPER alloy should not lead. Unfortunately, most reloaders do not cast, they buy from whoever and have no idea or control over the alloy used. The manufacturers warn against handloaded ammo on almost all guns I'm aware of to limit their liability. Regards