Tested 870 gr in NEF with our long
brass case with big primer.I have NEF
with extra hammer spring for big primer.
Got 2000 fps and still able to extract case.
Would do little more, extractor needs
to be wider and set up positive.
Used 260gr of WC-860 and MagPro.
Could use RL-22, Rl-25, Retumbo, etc.
That's 7700 ft lbs.. I get 600 gr slug to
2300 plus in NEF, long case. so you can go
light or heavy.Ed