I recently got an old rifle back in working order, a Remington 722 in .300 Savage. Here are details of the refurbishing I did to it.
After I got it done, I loaded up some test shells for subsonic work. All of the test loads shot 100% subsonic and stable, and the heaviest charge, while still staying subsonic, was the most accurate.
The .300 Savage is a great shell to run suppressed - it has a little less case capacity than a .308, making it easier to fill up with Trail Boss and still stay subsonic. The barrel in my 722 has a 1:10" twist so it can stabilize heavier bullets a little better. The thing that sucks is the bullet I used (180 gr Hot-Core round nose flat base) was discontinued by Speer, so I have a baseline, but I'm still going to have to work up a new load with a new bullet. I might try some 200 grainers to get a little more punch. And in a bolt gun, it's super quiet.
Cool. I like. Looks like my 300blk.