A little side project that I wanted to mess around with this winter was to see if I could get the remaining 95gr Nosler BTs (from a previous .243 Win project) to shoot out of my 6GT barrel.
I am also using N150 as the powder because I have 6lbs of it still, and no real project for it. It isn't as temp stable as others, so I'll have to keep that in mind as I'm messing with this stuff in the winter.
My goal is 3K FPS minimum, and 2/3 MOA @ 300 yards for 5 shots at least twice consecutively.
Doubt I'll hunt with it (it's a heavy ass AT-X), but so what? Itll be fun for me and I have a surplus of components...if that is possible.
Loaded 15 rounds and tried an uber-basic seating depth test today, starting at .030 and going to .075 in .015 increments. Just shot (3) groups of 4, and (1) group of 3. I did warm the barrel up. I shoot these in backwards order too (short to long)...Basically because if something shoots lights out all I have to do is seat the next group in a little bit and try to duplicate the results.
Anyway, .075 was UGLY. Well over MOA and vertically strung. .060 double grouped on me, then .045 and .030 hovered around the half-minute mark. Velocity for the two groups I recorded was right at my minimum with single digit SDs. I should mention here that my barrel has already done well with N150 and the 105 Hybrid at a similar charge weight, so this wasn't a shot in the dark.
It's a start. I'll load up some more in that seating depth window and play with charge weights a touch next. We'll see if it falls apart on round two.
Anyway, it's not a common/popular venture, but I figured I'd share.