I picked up a Stag 3L (AR-15) and set it up for predator hunting.
I find the 16" barrel and collapsable stock to be quite handy when slung across my back and riding my snow machine through trees. It's also comfortable to carry this way as the side of the rifle that lays against my back (right side) is smooth. I mounted a Weaver Super Slam 1-5x24mm "Dangerous Game" scope on it using Warne rings. The scope is excellent. It is very clear and bright. It can be used with both eyes open on 1 power and at 5 power has enough magnification to ring the gong at 400 yards reliably. I've also mounted a Surefire G2X Pro flashlight with red filter on the left side using a low Weaver ring. This isn't quite as much light as I'd like to have (200 lumens or 15 lumens) for night calling but I think it will work and is unobtrusive. I bought a Magpul 20 rd P-Mag to keep the setup a little more trim. Finally, I mounted a bipod adapter that fits my Harris bipods perfectly.
Including barrel break in I've only fired 110 rounds through it but haven't had any reliability issues.
I haven't spent a whole lot of time working on optimizing accuracy and have only tried one bullet/powder/seating depth combo. I started at 24 gr. IMR 4895 and worked up to 25 gr shooting over my chronograph. I found the most consistency at 24.6 grains and settled there.
For reloading I bought the RCBS AR die set (small base sizer and taper crimp seater).
Bullet -55 grain Hornady SP W/C "varmint" (B.C. = .235)
Powder -24.6 gr IMR 4895
Case -Lake City 09
Primer - CCI 41
COL - 2.185"
Average Velocity - 2638 fps
Completely repeatable 1.2 MOA 5 shot groups and produced a few 3 shot groups as small as .75 MOA. The velocity seems a little on the low side but actual bullet strike at various ranges matches pretty closely with theoretical strike from a ballistics calculator.
100 yds = +2"
200 yds = Zero
300 yds = -12"
400 yds = -34"
I have 200 55 gr Hornady V-Max W/C and I'm interested to see how well it slings those.
If I had more magnification I could probably make smaller groups but I like the versatility of the scope that's on it and it's already more accurate than it needs to be for what I bought it for.
Now, if I could just get some critters to come in before it warms up.