I'll say it, no one still makes a good long range stock for the AR, period, they are basically all different bowls of suck soup. We have the JP-SCS now, there's zero reason to force people to run a rifle length buffer tube.
PRS Gen 1/2: No recoil pad and no cant adjustment
PRS Gen 3: ridiculous LOP (15" on a Mega LR308 in it's shortest position) no option for shorter recoil pad.
LMT DMR: have to use their buffer tube, giant cheek rest, and you have no butt plate vertical or cant adjustment
Luth: All too flexy from the ones I've used.
XLR: Maybe the best compromise on paper, but from those I've looked at they just "feel" like they went a bit too lightweight.
The PRS Gen 3 is ridiculously long on a large form AR platform, and as much as this complaint is repeated I'm amazed no one is making a shorter recoil pad for it. The Gen 3 is basically 7/8" longer than the Gen 1/2. Also while the PRS Gen 3 can use a carbine buffer you won't gain any shorter LOP. Magpul at least could have figured a way to run it on a carbine buffer tube at a shorter LOP.
10 years ago everyone was going from crook of arm to tip of index finger, now it's more frequently recommended to be with the index finger in the 90 degree shooting position, which can easily be 1-1.5" shorter.
Some measurements (made from trigger shoe where your finger rests, parallel to barrel, to where the recoil pad ends:
DPMS LR308 Mega with PRS Gen 2: 14 1/8"
DPMS LR308 Mega with PRS Gen 3: 15"
AR15 Mega rifle buffer with PRS Gen 2: 13 1/2"
AR15 Mega rifle buffer with PRS Gen 3: 14 3/8"
For Reference:
Rem 700 5R Gen 2: 13 3/8"
Sako TRG - no spacers: 14"
M4 - A2 - 13.5"
Remington LTR (original version): 14"