If you have a Bear Creek Arsenal 7.62x39 upper/barrel youll need a 7.62x39 bolt. Some 7.62x39 BCG have longer enhanced firing pins to help ignite hard steel case military primers. The bolt face depth is the difference between 7.62x39 (.125) bolts and 6.5 Grendel bolts (.136). As BFT mentioned you have to use the bolt for which your barrel is chambered.
The only 7.62x39 barrels I ever heard of being chambered to use .136 bolt face depth bolts was Colt 7.62x39 AR-15 rifles back in the 90s.
There can be an issue of firing pin protrusion being out of spec in the AR-15 with AR-15s. The minimum spec for firing pin protrusion is .028 maximum .036.
I have never seen a situation where the 6.5 Grendel needed enhanced longer firing pins like is recommended for the 7.62x39 AR-15. There was only one source for steel cased Berdan primed 6.5 Grendel ammunition which was Barnaul which was also sold as Wolf Military Classic 100 grain FMJ.
The only 7.62x39 barrels I ever heard of being chambered to use .136 bolt face depth bolts was Colt 7.62x39 AR-15 rifles back in the 90s.
There can be an issue of firing pin protrusion being out of spec in the AR-15 with AR-15s. The minimum spec for firing pin protrusion is .028 maximum .036.
I have never seen a situation where the 6.5 Grendel needed enhanced longer firing pins like is recommended for the 7.62x39 AR-15. There was only one source for steel cased Berdan primed 6.5 Grendel ammunition which was Barnaul which was also sold as Wolf Military Classic 100 grain FMJ.