Appreciate you looking Mikey! As you noticed, the Magpul PRS is a great stock but on the heavy side, the DMR is much much lighter. Since you have a LMT 308 MWS, the DMR stock drops in (they sell a full kit or just the stock...in your case get just the 308 stock). I got mines from C3 Armory who is an authorized LMT dealer and they were the only ones who had it available. Not many places stock individual LMT parts.
Here's the advantage over the PRS, the DMR uses a milspec carbine type buffer tube (aka receiver extension). There's 3 types of buffer tubes: Rifle, Carbine, and the Vltor A5 style. Technically it's more as the carbine comes in both milspec and commercial and then you got things like PWS pistol tubes but for the most part those are the lengths you have to consider. The Vltor A5 is slightly longer than a carbine tube and shorter than the rifle tube. The 308 is different on a AR based platform as the buffer is shorter than a carbine buffer. With the LMT MWS it is the vltor A5 type length buffer tube so you can use a standard carbine buffer (H, H2, H3, etc...). The PRS must use a rifle buffer tube so if you wanted to install a PRS onto a LMT 308 MWS you would have to change out to a rifle buffer tube, 308 rifle buffer, and new spring. The 556 DMR will work on a MWS tube but the gap will be wider. On the PRS, they sell a retro fit kit to make the 556 PRS fit for a 308 in case you bought or have the 556 PRS.
As the MWS can change out barrels to accommodate different barrels, you can go from a carbine to a long range easily on the LMT. In the case you need a precision stock, the DMR would go on easily and quickly where the PRS would require tools and additional parts. On my LMT's the castle nut is staked on so if it's your first time removing it, it can be a PITA plus you need the AR combo wrench or the spanner.
As for fitment, both the PRS and the DMR have a adjustable cheekpiece which helps with scoped guns as it usually sits higher off the upper receiver's top rail. The larger scope objectives will obviously bring the scope up even more. You should try to shoulder one prior to buying the PRS or DMR. The AR 308 rifles have a longer charging handle coming back so the cheekpiece cannot be any closer relative to the receiver. For some it may be uncomfortable when you place your cheek to the riser and have a short eye relief on your scope (anyone remember the old school Delta cheekpiece on the scoped carry handled Colt's?
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I don't use monopods but for those that do, the bottom rail is a useful feature. One thing is that it's plastic not a metal rail.
Hopefully I explained it well, it's easier to show in person than to type it all out. Let me know if you have any questions. BTW, I will be doing a comparo of the Gen1 vs the current Gen2 SOPMOD stock soon.
-MW