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Old November 1, 2007, 02:15 PM   #1
jbirdfl
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glock barrel rifling

Another thread I submitted addresses the fact that lead should not be used in Glocks due to the rifling. With that in mind, what are the advantages and disadvantages of Glock's rifling? One school says these guns are indestructible and will eat anything you feed them. The other side makes them sound like finicky princesses as far as ammo goes. What gives?

Other than the 21, I also got a 30 and a 32 (357sig, now that's one I know nothing about, but it looks good in the reading I've done)
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Old November 1, 2007, 02:46 PM   #2
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Quote:
The other side makes them sound like finicky princesses as far as ammo goes.
Wow, not sure who you are talking to. I have a Glock 19 and a Glock 26, a friend of mine has a 17, 19, 26, 34, 29 and 20. We spend a lot of time at the range. I have never had any ammo issues with my Glocks (the 19 has about 10,000 rounds through it), and my friend has never had any ammo issues with any of his Glocks. My experience is if it will fit in the magazine, and chamber, it will work. The only issue I have heard of is that the steel cased stuff will have a tendancy to break extractors. I have shot just about everything imaginable through it, with the exception of lead bullets. I don't do that.
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Old November 1, 2007, 03:50 PM   #3
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Well it might be a factor of the lead bullet hardness, etc. So someone out there is making BLock barrels with normal rifling, I think, for lead shooters. But what the heck, go ahead and try some lead ammo in yours. Won't hurt a thing. IF it works good in your gun, then to H... with whatever anyone else says about it not working or something. Just be aware that lead builds up in barrels and needs a good cleaning to maintain accuracy. But with the kind of rifling a Glop has, without the sharp edges etc, it might be a much easier cleanup job too.
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Old November 1, 2007, 04:00 PM   #4
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Paging JohnKSa
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Old November 1, 2007, 06:05 PM   #5
Zombie Steve
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I'm not the world's premier authority on Glock barrels, but (call me whatever you want) the manual says don't shoot lead, so I don't. Never had a failure of any kind. The rifling in the barrel will supposedly boost velocity a bit.
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Old November 1, 2007, 11:04 PM   #6
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Glock recommends against the use of lead bullets in their pistols (though the manual is silent in terms of an explicit warning to that effect). According to Glock, at least one other expert in the field and some pressure measurements from a forensic engineer, the polygonal rifling can result in rapid barrel leading which causes dangerously increased pressures.

I know that some people do it and get away with it, and there are ways to much reduce the chances of having an incident, but unless you know them already, you really shouldn't be reloading for Glocks.

Polygonal rifling tends to be more resistant to wear, can offer higher velocities than standard rifling, and is generally easier to clean. The downside is that it's not such a good idea to shoot unjacketed rounds through it.
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Old November 2, 2007, 12:00 AM   #7
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ok, I've read a number of threads about not shooting lead through glocks due the the rifling and I don;t get it. my dad has owned one since late 80's? and I recently looked down the barrel after it was field stripped and I can't tell the difference from any other pistol barrel I have seen. Did they change barrels or something?

And about the unsupported chamber issue I places a round in the chamber (again the barrel was out of the pistol) and I don't see any difference. So what gives? I'm not sure what model he has, but its a 9mm.

And I own (pistols and rifles) and have been around firearms for as long as I can remember, so I know what rifling and a chamber looks like ;-)
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Old November 2, 2007, 01:04 AM   #8
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Quote:
I can't tell the difference from any other pistol barrel I have seen. Did they change barrels or something?
They've always been poly-rifled.

Looks, in this case, are deceiving. If you can recover a bullet fired from his gun (say an FMJ bullet fired into sand) you'll see from the bullet that the rifling is actually very different.

Here's an example fired from one of my Glocks. The deep gouges on the side and bullet base are not from the rifling, they're from rough handling after the fact.



And here's a closeup of the end of a Glock barrel. If you look down the bore, it looks pretty standard. If you look at the very end where the rifling meets the crown, you'll see that it's not standard rifling.
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Old November 2, 2007, 01:14 AM   #9
Dash
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glocks have rounded edges compared to standard rifling


http://www.glock.com/english/pistols_adv08.htm
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Old November 2, 2007, 09:05 AM   #10
jbirdfl
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Thanks for the info, guys. It is a lot clearer now.
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Old November 2, 2007, 07:12 PM   #11
Tom2
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Can't imagine why that would build up lead deposits any quicker than a regular rifled barrel with sharp edges. I understand that some 19th century rifles used that kind of rifling and they were shooting black powder and soft lead. Of course BP pressures are lower, but their reasoning at the time was that the "soft" rifling did not build up fouling as fast as normal rifling? Well we will keep watching, someone out there has tried it before and might have an experienced answer. But I thought it was the overall roughness of the bore, not the rifling, that was the biggest factor in leading?
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Old November 2, 2007, 07:46 PM   #12
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Here's what the late Gale McMillan, a noted gunsmith, had to say on the topic.
If you have ever tried to lap a polygonal barrel you will have a
better understanding why lead bullets and Glocks don't get along well. Its
the nature of a polygonal barrel that soft lead wants to skid across the
rifling and lock up. with a bullet it will actually shear the lead causing
high pressure. The harder the lead the less the problem. If you haven't
had trouble just be patient.
Gale McMillan
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Old November 3, 2007, 11:44 AM   #13
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Quote:
Originally Posted by Tom2
Can't imagine why that would build up lead deposits any quicker than a regular rifled barrel with sharp edges.
It is my understanding that the shallow rifling in a Glock barrel lends itself to an accelerated buildup of lead deposits. It makes sense to me that the deeper rifling in a traditional barrel would take longer to foul up with lead and would provide more avenues for the gases to escape. Because of the tighter case/bore fit in a barrel with polygonal rifling, less lead has to be deposited before pressures become unsafe. However, I am by no means an expert -- this was just the way I interpreted earlier posts on this subject.
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Old November 3, 2007, 01:12 PM   #14
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"Here's what the late Gale McMillan, a noted gunsmith, had to say on the topic.

If you have ever tried to lap a polygonal barrel you will have a
better understanding why lead bullets and Glocks don't get along well. Its
the nature of a polygonal barrel that soft lead wants to skid across the
rifling and lock up. with a bullet it will actually shear the lead causing
high pressure. The harder the lead the less the problem. If you haven't
had trouble just be patient.
Gale McMillan"

AKA 'stripping'.
If you fire a soft lead bullet at full power in a rifle you get the same thing.

The bullet metal is so soft the rifling does not actually bite into it, but shaves it off the bullet and smears it all over the bore.

Harder bullets will be more resistant, but there is still a maximum velocity a lead bullet can get to without making a mess in a bore.

The acceleration is rather abrupt, to say the least in a firearm.
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Old November 3, 2007, 08:47 PM   #15
Alleykat
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Quote:
I'm not the world's premier authority on Glock barrels, but (call me whatever you want) the manual says don't shoot lead, so I don't. Never had a failure of any kind. The rifling in the barrel will supposedly boost velocity a bit.
I don't shoot lead in my Glocks, and I just might be the premier authority on Glocks, but I've never read a Glock manual that says that you can't shoot lead through Glocks. How about giving me the page #?
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Old November 3, 2007, 09:20 PM   #16
JohnKSa
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I already addressed that in my post above. "Glock recommends against the use of lead bullets in their pistols (though the manual is silent in terms of an explicit warning to that effect)."

However, if you want the straight scoop you can contact Glock directly.

Or ask a Glock armorer--it's covered in the class. Wait, I'll do it for you.

JohnKSa (TFL Staff) to JohnKSa (Glock Armorer).
Hey, John, how's it going? What do they teach about lead bullets and glock rifling in the Glock Armorer's class.

JohnKSa (Glock Armorer) to JohnKSa (TFL Staff).
Hey, John, going fine. They teach that you shouldn't shoot unjacketed lead bullets in a glock pistol, the glock rifling makes that a bad idea.

JohnKSa (TFL Staff) to JohnKSa (Glock Armorer).
Ok, thanks for the information.

JohnKSa (Glock Armorer) to JohnKSa (TFL Staff).
No problem.

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Old November 3, 2007, 09:44 PM   #17
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I Like To talk To Myself Sometimes As Well.

Rasputin (TFL Member) To Raspu10 (Glock Talker).
Hmmm, Any Idea Why JohnKSa Is Talking To Himself

Raspu10 (Glock Talker) To Rasputin (TFL Member).
Mmmm, No Idea... Perhaps To Prove A Point.

Lol

Yes, Do Try And Stay Away From The Lead Bullets.
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Old November 4, 2007, 10:34 AM   #18
Alleykat
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John,

I'm well-aware that not shooting lead is covered in the armorer's course; however, that's not what was asserted in this thread. As I said, I don't shoot lead through my Glocks, even though I own aftermarket barrels for most of them. I just don't like handling/shooting lead.
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