I'm working with the Lee 55gr RF. I'm using HF red PC. So far I haven't shot anything hotter than 19gr H-4895.
This boolit relies on the gas check for rear bearing surface. Without the gas check there is only a small band of bearing surface in the middle of the body. I tried some without gas checks and the groups were about 20" at 50 yards. Shooting them without gas checks did not cause any problems whatsoever with the rifle. There was no fouling at all they just simply don't shoot accurately.
I'm thinking about removing the gas check diameter from the mould making it a non-check design. The PC has no problems with loads in this range.
I'm shooting a 16" 1-9 twist. Up until today 18gr H-4895 was my most accurate load with checks of course but today I tried 17gr and 17.5gr and the 17.5gr looks like it may be best. But even it isn't anything to brag about.
It all seems like a lot of work just to make a cast shooting 2000fps semiautomatic rifle that has mediocre accuracy. But hey, it's all just for fun. Right?
Motor