I bought a USS Plaster for 50 bucks used, just to play with. Having heard so many horror stories I had to see for myself.
Here's the deal;
It's HEAVY.
The stippling will chew right through gloves if you carry this thing very far.
You will be laughed at.
It's a bolt in, but you need to get some allen head action screws to replace the joke they call action screws.
The Remington and Savage stocks allow the action to rest in a V block. Lightly drill the block with a SMALL bit, skim coat it then set the action in. It will never move again.
I use mine to test new barreled actions because it is an incredibly stable prone shooting platform, more so than the AI, McMillan, or HS units.
Trust me, everyone laughs when I pull this thing out, but yesterday I was shooting waaaay sub 1/2 moa groups at 500 yards with it, and the laughter seemed to subside..........imagine that.
Bottom line, they do work.