12-06-2019, 01:22 PM
FLshooter Wrote:I would not waste my money on a BCG till I knew whether it is a t-1 or2. I’d go to a smith.They will tell you.T-1 get a 7,62x39 bolt.T-2 get a Grendel bolt.
Why not? There is no difference in bolt carriers.
A gunsmith can only tell if it is a .125 or .136 recessed bolt if they have the bolts and headspace gauges for the Grendel.
Better he get the true Grendel bolt (.136" recess) and do like Klem stated in a previous post. Get a factory load and see if it chambers. Given a true .136" recessed Grendel bolt, it a factory load doesn't go into battery then he needs the .125" recessed bolt. If the round chambers then shoot it and look at the brass to see if it has ballooned out or if it appears normal. I deliberately shot some brass this way to see if I could pack a bit more powder into the resulting stretched case. The experiment failed but I got a good look at brass shot out of a chamber cut for the .136" recess using a .125" bolt. It was pretty obvious. The shoulder and neck area was stretched out and quite a bit rounded.
I do not see any other way he can find out unless he can identify the barrel maker and then ask them. Problem is most barrel makers make both types.
LR55