Glocks are notorious for not liking Cast bullets. Something with their barrel reacting with the bare lead. The barrel gets fowled. I read it a long time ago but didn't pay much attention because I'm not a Glock person.
I have owned and enjoy Glocks -- have only one at the moment. I don't reload.
One professional shooter I know has put tens (by now, maybe hundreds) of thousands of cast rounds through Glocks over the years and says the secret is to work with lead hardness, lubes, sizing diameter and different powders to get a combination that did not lead the barrel. He also said you have to also keep your gun clean -- that "clean your gun every decade whether it needs it or not" stuff isn't appropriate. Most pro shooters reload to keep costs down -- unless the pro is on a team sponsored by an ammo maker -- and many shoot lead thru polygonal barrels.
Buffalo Bore, an ammo manufacturer has this to say at the following link:
https://www.buffalobore.com/index.php?l=product_list&c=59 Seems as though they have a LOT to lose if they haven't done their testing, research, and can back up their claims.
HARD CAST BULLETS IN POLYGONAL BARRELS
True hard cast bullets (as opposed to lead swaged bullets) that are properly lubed will not lead foul polygonal barrels any more than any other type of rifled barrel. Ever since Glock Corporation warned to not use lead bullets in their pistols with polygonal barrels, a myth that hard cast bullets will lead foul polygonal barrels has become wide spread in some parts of the firearms world. However, the myth is untrue. Hard cast bullets are not "lead" bullets. (See my article on "Dangerous Pure Lead Cowboy Bullets")
Pure lead or nearly pure lead bullets have a tendency to foul any barrel, not just polygonal barrels. Years ago, when several Glock pistols experienced cracked barrels because of fouling build up from shooting pure lead bullets, Glock issued a warning not to shoot lead bullets in their polygonal barrels. From that warning, the myth that you should not shoot hard cast bullets in polygonal barrels was born.
Provided you use real hard cast bullets with good lube, you can shoot them all you like in polygonal barrels without causing lead fouling deposits at the front of your chamber or anywhere else in the barrel. If you are concerned about lead fouling from hard cast bullets, all you have to do is to clean your barrel after firing hard cast bullets and before firing any jacketed bullets. However, in my experience, quality hard cast bullets won't foul a Glock polygonal barrel or any other type of barrel but lead bullets normally will.
If you reload and feel you must shoot lead, but remain wary of using lead in a Glock barrel,
aftermarket barrels with lands and grooves are available and most of the prices are low enough ($125-$175 +/-) that you''d save enough pretty quickly shooting lead to offset the purchase price.
If you're concerned, don't want to buy an aftermarket barrel, just don't do it.
Do a Google search on "USING LEAD IN POLYGONAL BARRELS" and see what you find -- and note that most of the folks warning against using lead aren't talking from personal experience, while many who do tell you how it can be done safely
are speaking from -- in some cases -- years of experience.
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