Thanks for the detailed answers, lots of things to think about!
I have a chrono, but lately my range time has been limited. It seems that every time I pull my chrono out, then 5 other shooters show up (which burns more time explaining that yes, suppressors are in fact legal
and no, I don't work for the government or military as an assasin, followed by - "I got to get me one of those!, How do you get one? $600 for the suppressor + $200 to the BATF, fingerprints to the FBI...oh, ok) if I don't bring it, I have the range to myself for a day. I'll need to take a day and do it.
I made my 300/221 brass out of LC brass, but as I look at them, it's of various years - 03, 06, 07. I'll weigh cases and sort. I've loaded this brass 4x so it's well formed by now. Neck tension seems consitent when seating the bullets, "normal" to othe cals I've loaded as far as I can tell with my hand on the press lever. I also put a light crimp on with a custom Lee Factory Crimp die.
I was testing loads on my 30BR bench gun the same day, and shooting moa and less the whole session with it, so I'm confident it isn't totally me.
Just checked the rings, they're tight. The suppressor mount seems perfectly centered (my 'smith is a very fussy machinist).
Some Questions/comments:
rsilvers: Why increase to 2.120"?
snipecatcher: I just realized that I didn't bring home my last set of targets from the AR session (I left the range thinking "what did I forget?"), but I do have some targets from testing a couple loads from the Savage. I might say there is a hint of "off center" in the holes- -not much, but maybe a little. Hmm. Definetly something to investigate further. I'll see if I can get it on paper out at 200 and see what they look like there. I Just checked the barrel with a rod and bore brush, and the twist is right on 1 in 8".