I think the whole SR vs AMR ordeal really just boils down to preference. I've yet to use either one one, although I'm looking forward to going sniper... preferably silenced. :rock:
The standard sniper rifle can accept a suppressor, which makes a
big difference. With the sniper rifle you can pick off an entire horde of people, one at a time, with none of them having any idea what's going on. The AMR is hands-down more powerful (unless you use the [censored] .308 JSP handloaded rounds), but you're only going to get off one or two shots before everybody within half a mile converges on the sound of your light artillery touching off.
Personally I would have not added a suppressor for either weapon. You already have suppressed versions of both a pistol and SMG chambered in.22LR and 12.7mm, and the 10mm pistol. Choosing to go stealth should force you to use lighter weapons, it shouldn't be a "yeah, this is one of the most powerful weapons in the game
and silent". Should be either/or. The sniper rifle and AMR give up any semblance of quiet in exchange for being very powerful, very long ranged, one-shot fight enders.
But on topic, I think I'll have to agree that the rolling pin the is worst weapon. Even somebody with no unarmed skill at all probably does more damage with their fist.