I was working up loads for my 6arc using the 90 Sierra TGK. I was loading RP 7.62x39 LRP brass that was first fireformed to 6.5 grendel then necked down to 6 arc. I had some break in ammo loaded with that bullet and I think 25g of Varget. It ran the gun fine. 2640fps.
I tried a work up with 4166 started at 26.5 and worked up to 28. I shot them across the chrono and they ranged from about 2730 to 2840. But none would lock the bolt back or fead another round. I thought the bolt was running to fast or it was having trouble unlocking because pressure. So I loaded some at 25g and tried again. Still barley ejecting at 2650.
The 4166 ran the rifle ok with 105g hornady hpbt bullets, but I assume it doesn't have enough gas volume to run the action with the lighter bullet despite the velocity numbers to charge weight being almost identical to varget.
It runs great on 65 vmax and 8208 also.
I tried a work up with 4166 started at 26.5 and worked up to 28. I shot them across the chrono and they ranged from about 2730 to 2840. But none would lock the bolt back or fead another round. I thought the bolt was running to fast or it was having trouble unlocking because pressure. So I loaded some at 25g and tried again. Still barley ejecting at 2650.
The 4166 ran the rifle ok with 105g hornady hpbt bullets, but I assume it doesn't have enough gas volume to run the action with the lighter bullet despite the velocity numbers to charge weight being almost identical to varget.
It runs great on 65 vmax and 8208 also.
