I bought a Glock-17 the other day and I was wondering what the AT stands for and the pentagon with a dot in the middle this is all on the barrel. Wondering if someone knows what it means???
Unconfirmed, but I've been told it's just part of the proof marking and signifies a polygonal rifling either hexagonal or octagonal. I've not been able to get anyone who knew why some have a dot inside and some don't..............
It's confusing I would like to know what it means cause my glock 22 don't have the AT but has the pentagon
From what I've heard the pentagon symbol signifies the grade of steel that the barrel is made out of. In my experience, the old black-coated barrels that had a regular pentagon were a softer steel than the new gray-coated barrels which have the "dotted" pentagon.
