Glock pistols and lead bullets

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Georgezilla
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Glock pistols and lead bullets

Post by Georgezilla » Tue May 17, 2011 2:10 pm

Glock advises against firing lead bullets (non-jacketed) out of their pistols. Does anyone know why they warn against using lead bullets?

I assume it has something to do with the polygonal rifling they use in their pistols. However, Kahr also uses polygonal rifling in many of their pistols and they only warn that it will cause significant leading in the barrel. I was thinking that perhaps using lead bullets in a Glock would cause the same problem with leading, but perhaps due to the Glock design, the leading is more of an issue; which would warrant Glock to advise completely against the use of non-jacked lead bullets.

Any light shed on the top is appreciated, thanks.

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Post by blue68f100 » Tue May 17, 2011 3:15 pm

Your on the right track. With the polygonal rifling it's harder to get a lead bullet to seal off, larger gap than normal. I know of a few that shoot lead in theirs and leading is an issue till you find that perfect load for that gun. Most had to cast there own so they could shoot softer lead and size the bullet larger. Now for a little more money you can get a Copper jacketed which eliminates the issue. Or you could change the barrel out to a std one.
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Georgezilla
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Post by Georgezilla » Tue May 17, 2011 4:36 pm

Thanks for the reply, Blue.

I read that polygonal rifling yields a slightly smaller bore area than conventional rifling. I figured that this would cause more of the lead to be shaved off in the polygonal barrels resulting in heavy leading. However, based on on your experience shooters who use cast lead in polygonal barrels size their bullets UP, so that seems to blow my theory out of the water.

Even though polygonal barrels have less bore area, perhaps the valleys in the polygonal barrels are lower than the grooves in a conventional barrel? This would give the lead more room to accumulate.

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Post by Medicine Hat » Tue May 17, 2011 5:41 pm

That. And I think, it gives the powder gasses a channel to erode more lead from the bullet, especially if they are undersize compared to the bore.
Polygonal bores have been around for over 100 years, but not popular (unitl Glock), and probably for good reasons.
Just my thoughts.

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Post by Hakaman » Tue May 17, 2011 5:50 pm

I purchased a drop in barrel from KKM to get a different rifling style, and better case support.
http://www.kkmprecision.com/custom_pist ... =23&page=1
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Post by Georgezilla » Wed May 18, 2011 12:59 am

Thanks for the insight everyone! MH, that is a true statement. I read in a firearms history book that traditional and polygonal rifling were basically developed at the same time.

Upon further research, "polygonal rifling" is very ambiguous. Kahr arms and Glock's rifling are both polygonal, but they are indeed different, hence why there is more of a problem using lead bullets in a Glock. The Kahr's use a polygonal rifling style designed by Loather Walther which apparently has about the same bore area as a conventional rifled barrel. On the other hand, Glock barrels use a different style of polygonal rifling which results in a smaller bore area. I suppose Glock's process just produces too many places for the lead to go. Since Glock pistols are primarily manufactured for LEOs and the Military, I guess it does not make a huge difference seeing as in these roles the ammunition one uses would have a jacket.

Haka, good move with the barrel. I know there are a few after market Glock barrel makers, would you recommended KKM? Did the barrel require any fitting?

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Post by Hakaman » Wed May 18, 2011 10:48 pm

Haka, good move with the barrel. I know there are a few after market Glock barrel makers, would you recommended KKM? Did the barrel require any fitting?
I can't speak for other manf barrels, but the KKM is a very good after market barrel.
It is a drop in, without any fitting needed. KKM takes a lot of pride with their products,
and excellent CS. It is a stainless steel barrel/finish, which IMO, is sharp looking.
Haka

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Post by blue68f100 » Thu May 19, 2011 8:57 am

Unless your casting your own bullets you can get Montana Gold for almost and sometimes cheaper than plated bullets. If your casting your own you can find a harness and load that works with your gun.

I know for a fact that the polygonal barrels will strip the plating off a plated bullet. So these are out.
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greener

Post by greener » Thu May 19, 2011 6:31 pm

The Glock barrel was supposedly sensitive to ammo. Firing lead bullets was supposed to lead to the infamous Glock kaboom!. I don't think it has been verified.

http://www.thegunzone.com/glock/glock-kb-faq.html

I know folks who shoot lead bullets in standard Glock barrels with no problems. I believe they pay a bit more attention to cleaning the barrel than they might with other barrels. Some shoot IDPA, so the Glocks get a lot of lead bullets.
you can get Montana Gold for almost and sometimes cheaper than plated bullet
I shoot MG 9mm bullets in my SR9. I've had a very positive experience with these.

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Post by Bullseye » Thu May 19, 2011 9:05 pm

I have not done any definitive testing with Glocks and lead bullets which is why I've not commented on this thread. All mine have had a steady diet of jacketed ammo.

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Post by Georgezilla » Thu May 19, 2011 9:09 pm

Thanks for the info guys! Well, for my purpose the point seems to be moot. My brother recently got a G27 (.40 S&W) and I inspected the cases he fired from it. Every case fired from it was bulged; I should mention that all cases were Winchester white box. After some research, this condition is apparently "normal" in Glocks chambered in .40 S&W. These cases obviously can't be reloaded, so in order to reload cases fired from a .40 Glock, a new barrel is needed (which would allow the use of lead bullets without concern).

The .40 bulge is apparently caused by Glock chambers being loose, not from the case lacking support at the feed ramp/throat.

I am still wondering though, is .40 S&W Glocks' tendencies to to bulge cases as common as the research on the internet leads me to believe? Or is this something that is uncommon and that I should advise my brother to contact Glock about?

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Post by blue68f100 » Thu May 19, 2011 10:13 pm

They can be reloaded. There is a scpecial sizing die to remove the bulge. It's similar to a sizer used for sizing lead bullets. It's push through die.
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Post by Bullseye » Fri May 20, 2011 6:23 am

I haven't inspected any of my G-27 empty cases. I'll see if I have some around and check for bulges.

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Post by blue68f100 » Fri May 20, 2011 9:28 am

Here is a link for the Redidng G-Rx die used to remove Glock bulge.

http://www.midwayusa.com/viewProduct/de ... ber=358543
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Post by Medicine Hat » Fri May 20, 2011 10:33 am

I use the same die for .40. It works well.

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