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Post by BlueSteel on Apr 3, 2004 19:11:17 GMT -5
I just finished purchasing a new walther P99 9mm today ;D and the guy told me that it had the new polygonal rifling and i can shoot lead bullets.
Now i thought that lead was bad for polygonal rifling especially in glocks.
What do you guys know about Polygonal Rifling?
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Post by "DoubleAction" on Apr 3, 2004 19:19:02 GMT -5
The Polygonal Rifling does not have the conventional lands or grooves found in standard rifled bores, and because of this, friction in the bore is reduced.
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Post by MLB on Apr 3, 2004 19:23:21 GMT -5
I have a P99 in .40 that I bought last year. It does not have polygonal rifling. I have not heard of Walther using polygonal rifling in any handgun. Maybe they just started, but I don't think so...
You're right about using lead in polygonal rifling barrels though. Not recommended due to lead build up. I do not understand why lead would build up any faster with this type of rilfling as opposed to traditional lands and grooves though. Any poly experts here?
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Post by BlueSteel on Apr 3, 2004 19:30:36 GMT -5
Yea i also thought the p99's were land and groove too but the guy said 'the new polygonal barrel' so i assumed it was an upgrade. But i haven't been able to find anything on the internet mentioning it.
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Post by MLB on Apr 3, 2004 19:41:21 GMT -5
We have a few Glock and H&K owners here. Can you tell the difference by sight? I'd think you'd be able to see the difference.
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Post by TMan on Apr 3, 2004 19:50:19 GMT -5
Can you tell the difference by sight? I'd think you'd be able to see the difference. I don't know how obvious it is on different models, but on my MRI Baby Eagle it is very noticable by looking down the barrel. I didn't know what I was looking at when I first looked down the barrel, but after checking the specifications it then made sense. |
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Post by BlueSteel on Apr 3, 2004 19:55:29 GMT -5
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Post by Ricochet on Apr 3, 2004 20:58:48 GMT -5
Just what I've heard:
(1) Walther P99's do not have polygonal rifling.
(2) Glocks use polygonal rifling and recommend not using lead bullets.
(3) H&K uses polygonal rifling and doesn't specifically recommend against lead bullets.
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Post by Callahan on Apr 4, 2004 3:08:06 GMT -5
This is a really interesting thread and I'm interested in learning more about it. I have to confess I don't know beans about polygonal rifling other than what I've read about it related to Glocks.
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Post by XavierBreath on Apr 4, 2004 7:03:44 GMT -5
 This is one of the best pics and explanations of why no lead in a poly barrel I have seen. You can see the difference by looking down the barrel. Compare it to a regular barrel. No lead in a poly barrel, OK? |
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Post by Ricochet on Apr 4, 2004 11:43:03 GMT -5
Yep, that picture is very good for explaining what polygonal rifling is. You can go to that link and find a comparable picture for the broached rifling.
But the picture itself doesn't tell me "no lead".
I have heard that the polygonal rifling has a tendency to strip lead from "lead" bullets resulting in buildup in the "valleys" of the poly-rifling. This can result in higher pressure build-up during discharge and perhaps eventually lead to a kaboom.
Some have said that more frequent cleaning (with careful attention to lead removal in the barrel) can prevent any problems. I.e. it is a manageable risk.
However, the fact that there is a "possible" problem here is reason enough for the manufacturer to recommend "no lead".
I guess what I'm not sure of is why there is not talk of a similar (even if less severe) problem with conventional broached rifling. Perhaps it is just a matter of degree, or perhaps there is something about the broached rifling that lets the lead just fall out rather than build up.
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Post by MLB on Apr 4, 2004 20:54:50 GMT -5
I'd be very interested as to why lead would accumulate faster in a barrel with polygonal rifling. If I hadn't heard otherwise, I'd have thought that the "bumps" of the polygonal rifling would collect less lead than the sharp edges of the traditional lands and grooves.
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Post by BlueSteel on Apr 4, 2004 22:08:53 GMT -5
From what ive read, the polygonal rifling grips the bullet tighter but causes less friction because there is no 'cutting' of the bullet. I guess that means the lead has a place to go in the traditional land and groove style. Someone correct me if im wrong tho.
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Post by Arclightstrike on May 31, 2004 18:12:52 GMT -5
I have heard directly from a Glock rep that if your Glock self-destructs and you were found to have fired plain lead (not jacketed) projectiles through it, your warranty is void. It is because the polygonal rifling does, by its design, "grip" the bullet more tightly (positive contact with a greater surface area of the bullet surface) than traditional land-and-groove rifling. Apparently this can smear more lead off a plain lead bullet as it travels down the bore. The added resistance of the lead build-up in the bore on the bullet soon causes pressures to exceed acceptable limits, as with each shot more lead gets smeared into the bore. Since it is not possible to verify how often and well a shooter will clean the bore, Glock simply does not warranty any KB'd pistol which was used with unjacketed ammo.
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