Mostly, it's follow-up on earlier projects. In the case of the M1A, I've tweaked the sling setup a bit. I like the sling overall, but the straps making the front adapter require disassembly in order to get the stock off.
Midwest Industries, again, had what I was looking for. They make a short Picatinny rail that clamps to the gas cylinder of the M14, and a clamp-on sling swivel. Here it is on the M1A, prior to putting on rail guards (no mini cheese grater for me).
Again, nothing touches the barrel itself, so sling pressure should have no bearing on a changing point-of-impact. With everything all back together, and plastic guards on, this is the final result:
Now if that Aimpoint CompM4 would just arrive....
And I finally got around to replacing the low-profile rail guards on my Mossberg 590 forend with some full-profile covers that actually work. These semi-soft Magpul covers are a little hard to put on, but the final results are worth it.
It now feels round, like the handle of a pump shotgun should. And no chance of grated hands.