All,
Thank you all for the feedback. My takeaway from this is there are max ‘book’ loads that reach my goals in 24” barrels, a factory GMX that is on goal, and a couple of suggested loads that get there. It seems 3000 fps is reasonable, so I am going to get a 6.5 CM.
As a recap, here are the book loads you all pointed out that nominally meet my 120 gr muzzle velocity goal with 24” barrel:
Alliant - RL16
Hogdon - StaBALL 6.5
Nosler - H4350, RL17, Hunter
So 5 different powders. There were several others very close.
As my username suggests, I like short rifles. Looks like I need to make an exception for this project. For engineering margin, I’m going with a 26” barrel.
Thanks again for your support!
Your goal of 3000fps in 6.5CM w/ 120 TTSX is easily done w/ a 22" or 23" barrel. Especially if you are talking about having a rifle built w/ a custom barrel. As has already been suggested, look hard at the 127LRX - 2950 is easily achieved w/ a 23" barrel and it's higher BC means it retains more velovity at 450yds than the 120TTSX started at higher velocity. LRX's seem to open easier than the TTSX's also.
David
