This is such old news i dont think its worth a mention.
Actually, there's been some changes regarding Glock barrels.
Gen 5 Glock 17s now have GMB (Glock Marksman Barrel) with additional ridges along each hexagonal rifling -
https://www.ssusa.org/articles/2017/9/1/preview-glock-gen5-pistols/
Here are close up pictures -
https://www.glocktalk.com/threads/gen-5-barrel-rifling.1686073/
https://blog.thegunsandgearstore.com/polygonal-rifling-in-glocks-why-it-matters/
Don’t Shoot Lead Bullets through
Glocks (Polygonal Rifling) – FACT
Lead bullets can foul polygonal rifling very fast and create an obstruction before you finish shooting an entire magazine in some cases. When people talk about catastrophic failures, this would be it!
Hey guy,s I,m wrong on this . If the lead is (HARDCAST) it,s ok to use. I appologize for submitting the thread, I was wrong. First time I read the first article I guess I was in a hurry to advise people .I should have researched it more.
https://www.egglestonmunitions.com/...-polygonal-rifling-will-these-run-in-my-glock
Not really. There's the issue of leading and accuracy of shooting lead bullets in Glock barrels -
https://www.thehighroad.org/index.php?threads/cast-bullets-in-a-glock.750685/#post-9451186
Disclaimer: Like many other pistol manufacturers, Glock does not recommend shooting reloads (including lead reloads), so use reloads in your Glocks at your own risk.
Now that we got the disclaimer out of the way, can you shoot reloads in your Glocks, including lead reloads? I can't speak for other Glock shooters, but I have for about 25 years now (including lead reloads) with some consideration. BTW, what do countless Glock match shooters (including factory Glock team) use for match shooting week after week all around the world? You got it, reloads.
As to shooting lead reloads in Glock barrels, there are several more considerations. These are considerations for shooting lead bullets in any barrel:
- Commercial lead bullets come in different hardness ranging from softer 10 BHN to harder 24 BHN.
- Lead bullets come sized .001" larger than jacketed bullets and can be obtained sized .002"+ larger.
- Proper hardness/bullet to barrel fit/sufficient powder charge need to be used to properly deform the bullet base to seal the high pressure gas as gas leakage/gas cutting leads to increased leading.
Glock barrel showing smooth hexagonal rounded rifling.
Glock barrel showing smooth gradual start of rifling with longer leade
There are issues specific to Glock barrels (see picture above):
- Glock barrels have longer leade (space the bullet jumps from the case neck/chamber to the start of rifling) which increases high pressure gas leakage.
- Glock barrels have very smooth start of rifling with rounded rifling which allow the lead bullet to slide deeper into the barrel before sufficient chamber pressure starts to develop which further increase high pressure gas leakage.
These Glock barrel features allow more high pressure gas leakage around the bullet which results in more of the following:
- High pressure gas leakage around the bullet blows liquefied lube from the bullet and down the barrel which may increase fouling/leading build up, especially near the chamber end of the barrel.
- If high enough powder charge is not used, powder burn may be inefficient and insufficient/inconsistent chamber pressures may not deform the bullet base to allow the bullet to "skid" down the barrel and increase fouling/leading build up.
Unless you use the proper hardness/sizing of lead bullet for the powder/charge used that produce sufficient chamber pressures to minimize fouling/leading build up, it is a good idea to inspect the Glock barrel more frequently for fouling/leading build up. So more careful load development/powder workup may be required. rcmodel usually recommends inspecting the Glock barrel around 200-300 lead rounds and I found this to be a good interval as loads that produce fouling will start to decrease accuracy above 300 round count. If your lead loads produce fouling/leading at lower round count, inspect the barrel more often and clean as necessary.
This is Glock barrel after 100 rounds of lead rounds shot through. At the chamber end on the left picture, you can see loose flaky residue which is less of an issue but see sticky fouling build up forming at the base of rifling. At the muzzle end on the right picture, you can see the start of crusty fouling build up. These fouling build up IS NOT leading and will remove easily with a quick Hoppes #9 solvent soak and copper bore brush. BTW, bullet/powder used were MBC 124 gr RN (SmallBall) and W231/HP-38. Even after several hundred rounds, I do not get leading in Glock barrels with this load, just fouling build up.
Also, while I seat 9mm FMJ/RN plated bullets deeper into the case for greater neck tension and more consistent chamber pressures; with lead bullets, I use longest working OAL to minimize gas leakage for faster pressure build up to deform bullet base and seal with the barrel (that will compress the lube channel to form an "O-ring" seal) -
http://www.lasc.us/Fryxell_Book_Chapter_5_Lubrication.htm
As to shooting powder coated/Hi-Tek coated bullets in Glock barrels, the coating acts as lube and prevents leading of the barrel.
I have shot MBC 18 BHN lubed lead and Hi-Tek coated bullets in my Glocks and have not experienced leading of the barrels.
For comparison, picture below shows KKM barrel with square cut land/groove rifling with freebore and sharper start of rifling (Slower 1:24 barrel twist rate that produced greater accuracy with lead bullets for me)
Lone Wolf barrel showing square cut land/groove rifling with short leade and sharper start of rifling (Typical 1:16 barrel twist rate of most match barrels more compatible with lead bullets)
