I have an Mk12 SPR in my inventory as well. Looted it off of a dead guy near the tracks in komarovo. buzzing flies, and i did think it was quite peculiar that it came with 6 clips, and almost nothing else of import. well, it had civvy clothes some food, and all including a coyote backpack(Score! right?) but i too went searching for info. not on the site, so i searched elsewhere brought me here. All moral judgements aside, it took EXTREME fortune to come across it, over the entire land, at the right time and such.That being said, i will keep it until i find a suitable replacement. That ALSO being said, i continue to use my trusty, rusty hatchet because big loud guns are big and LOUD. Yay for stealth. ;)