It is generally accepted that the geometry of the riflings (such as they are) on a Glock barrel (not having the standard grooves and landings), that lead will accumulate faster on the ridges (in a phenomenon called "cladding"), to such an extent that the cladding will eventually change the internal diameter of the bore, possibly leading to catastrophic bullet stoppage or dangerously increased pressures when firing which could lead to catastrophic chamber or barrel failure, neither of which is a good thing to have happen.
With that being said, there are Members who shoot lead bullets thru their factory barrels and report no issues, but if done, it must be with a warning that the bore must be cleaned with a lead solvent to prevent this buildup.
Should a failure of the chamber or barrel occur, when shipped to Glock for warranty repair, they may decline repair under warranty due to traces of lead cladding, as a violation of the terms of warranty coverage.
It is a case of "you can if you want to, but know the risks and maintain a vigilant cleaning regimen."
I myself would never shoot bare lead ammo thru any of my guns except the revolvers. The ammo may be cheaper, but the extra cleaning of the bore is a royal pain in the behind.
My views and opinions may not necessarily reflect those of Glock Forum, its management, its owners or affiliates.
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