I'm a bit of a snob when it comes to firearms, so I personally avoid KelTec like the plague. I've heard issues with the MDR as well, like the polymer inside the stock cracking. They are pretty accurate though, since they're built by a company who make sniper/marksman style rifles. If you want a .308 bullpup, take a look at the Tavor 7. IWI really knows their shit. If you're OK with going with a more traditional style rifle, I can't recommend the LMT MWS308 more highly. It's an excellent rifle in service with the Brits, Ausies, and Kiwis in the DMR role. It has a quick change barrel feature, and LMT offers several different lengths and calibers in chro-moly and stainless steels. I absolutely love mine. It's my "go-to" rifle if things ever get "bad" and I've got two uppers for it: the railed upper that came with the rifle with an Elcan Spectre TR scope (plan on putting a 20" stainless barrel on it) and a lighter upper with M-Lok slots that I'm building up with a 16" barrel and either a red dot or ACOG optic. That way I can just swap uppers for which ever role I need the rifle to be configured for.
Edit: decided to quickly mount my new US Optics scope on my MWS308 just to kinda show how it'd be set up for the DMR role. An 18" or 20" barrel would be better suited for a DMR setup, but I've only got the 16" barrel right now.
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