300BO Subs
Hey everyone.
I started reloading 300 subs recently to run suppressed. I'm working with 208gr ELDM over various quantities of AA1680.
I started a ladder test at 11.0gr of powder and had an average that was a little slower than book at 1070fps (10.5" barrel rather than book's 16").
I ended up cutting the test short (they were already supersonic at 11.6gr) and only shooting 3 ladders with 9 shots total.
One thing i noticed is, my second shot in each ladder (3 shots at each powder charge increasing by 0.3gr) were noticeably faster (by almost 100fps) than my first or 3rd shots in each of my ladders.
My question is, can this be caused by shooting a supressor "dry?" Is this just because the charge weight is so low to begin with? Why the jump of almost 100fps? Is this just due to a small sample size?
Just trying to whittle down some variables that others may know about.