A couple months late, sorry. New to M4C, but not to building AR's. I recently built the "F-U A-hole" gun Diamondback referenced in 300 Blackout, just to see how it would work, thought it'd be a fun project. Have the Law Tactical folding stock and the LEO takedown. Also used a FAB defense folding grip, a FORTIS Switch handguard, and a Sidelok Scope mount from Kinetic Development. Lots of moving parts, for sure, but I can break it down into 3 main pieces (lower with folded stock and folded hand grip), barrel/HG assembly, and scope/mount. Takes about 3 seconds to take apart or put together, total space when laid side-by-side is about 18" long x 9"wide by 6" high, and that's with a Faxon 16" Gunner barrel. Easily fits into a backpack or duffel bag.

Right now, as you might imagine with all the moving parts, shots are kind of all over the place. I've got groups down to about 4" at 100 yards. Doesn't sound very impressive, but when I first started out, there were some shots that didn't even hit the target. A tweek here and there, and it's getting better. Using S&B FMJ 124 Gr. ammo for the most part. Better ammo should help close the groups.

I pretty much have it down to 2 main areas of concern. 1: the Fortis HG loosens over time, especially if using a rail mounted bipod. May have to change to a permanently mounted HG. 2: The LEO takedown also comes loose. There are 4 very tiny set screws that lock it to the upper that come loose fairly quickly (I used blue loktite). IMO they are way too small, may have to open them up and go bigger for a better bite. Loose enough that a couple times the LEO coupling actually separated, pushing the barrel forward about 1/2". I noticed it only after I loaded another round and the gun went "click" as the ammo was too far away from the firing pin. I see on their website they have a new installation video, where they recommend using Rocksett instead of Blue loktite. I'm going to try that soon and see if it keeps those little set screws from backing out (heat might be the problem). This may also be why the Fortis HG comes loose, since the barrel nut is mounted to the LEO. The Fortis Switch is nice in order to adjust the gas block, also to clean/oil the outside of the barrel once in awhile.

I will say that all of the products used seem well made. None of them have that cheap feel, indeed they all feel like heavy-duty/quality. The Kinetic Dev. Scope mount is very heavy duty- have yet to try it on another gun to test for on-off POI shifts, but in my limited testing with this gun, it does not seem to, at least out to 100 yards - but hey it's 300 Blackout so don't plan on shooting it further than that anyway. Just a summer fun build/range toy. Probably put too many moving parts on one gun to expect too much.