Thanks for your input here Mike.

Quote:I found one line of load data for IMR 4350 powder in an old reloading manual to use as a starting point. 36.8 grains was supposed to yield 2100 feet per second (fps) for the 140 grain bullet and 34.0 grains was supposed to yield 1900 fps for the 160 grain bullet.

That's interesting.
I fired 12 rounds of 140gn SST with 37gns IMR4350 last Saturday...just to get the scope/rifle lined up on the paper. Just a test load to see what it looked like. No pressure signs & no chrono work done. Group was 2" or 1" MOA. But I didn't have enough rounds after getting it onto the paper to form a proper opinion.
I'm sure it won't take long to generate an accurate enough load with the 140gn SST & IMR4350

But really, the rifle was designed with the 160gn bullet in mind, so that's what I'd really like to develop.
Following some data received from a friend, I'm given to understand 37gns of IMR4350 pushing a 160gn bullet is moderately hot. I'll try 1 round and have a looksee. If it is too hot I'll readily abandon it and moderate accordingly. I suspect most of the propellants I have at present are on the 'slow' side, but we'll see.
Best wishes, d.