01-24-2018, 05:54 PM
Using the tumbler to vibrate the cases, also used a tooth brush for some to settle the powder to fit more in the case. I got over 2600fps (123gr SST) from the boltaction and it's 22 inch barrel, that load was on the hot side for sure and no doubt compressed. Was able to get 2500 from it though with a little primer flattening but no craters on the primer and was using up some Winchester SRP that were handy so with that thinner cup not surprised with some flattening. Switched to 130 and 129s mostly but get my health back I plan on working more with 4166. Like Varget in the Grendel you will hear some crunch seating the bullet but it appears it could be a good powder for accuracy and ok on speed within pressures for the GRR if you don't mind a little crunch seating the bullet.