With 10.3" Daniel Defense chf mk18 barrel w/pinned DD gasblock and DD fh. That's the heart of this build. Receiver set is 7075 T-6 billet aluminum to mil-spec dimensions with tensioning screw in lower from Next Generation Arms (NGA was a high end AR manufacturer in early to mid 2000's who went out of business and I bought several receiver sets from them as they were selling off their residual inventory - http://www.defensereview.com/shooti...h-tactical-ar-carbine-3200-round-test-report/ This upper is a slick side upper so it has no FA, only a shell deflector. Super nice machining and anodizing. Tolerances are on the money AFAICT with the BCM LPK. Super flared magwell on the lower, integral trigger guard too, and the tension screw. Brace is the SBA3 unit which is excellent and uses a standard carbine buffer tube. Rail is somewhat of a budget affair from Guntec, still wasnt cheap though. Through the only 90 rounds I've fired through this it seems to be just fine though. Solid and light as a feather. M-lok. Trigger is a Geissele SSA-E 2 stage. Here's a complete list of the components- DD mk18 10.3" barrel w/pinned DD Gasblock DD flash suppressor NGA 7075 T-6 receiver set w/slick side upper SBA3 pistol brace w/ carbine 6 pos tube, H1 buffer and carbine spring Guntec 10" m-lok rail BCM LPK BCM Mod 4 charging handle BCM Mod3 grip Toolcraft BCG Geissele SSA-E 2 stage trigger CMMG ambi safety w/ short right paddle Arisaka m-lok QD sling attachment point No BS here guys and gals, this thing has but 3 30 round mags through it. It's new. It functions 100%. This barrel is NOT overgassed by any measure. It is my first and only pistol and I really expected, even for a 5.56, some more pronounced recoil but I have to say I was very pleasantly surprised by the smooth impulse and utter control ability when I shot it. I really liked it. You ever just get an idea that you want something just because its different or because you dont have or never had one? Well, that's the reason I have this, and the reason also that I'm selling it. Just about all of my ARs are geared more towards the precision aspect of shooting. Making tight little groups on paper targets is more my game and while very fun and shoot able it's just not my preference. I'm not an operator clearing rooms in a drug house somewhere. I like to set at my bench and strive for those little groups. So I'll let it go, for $725+ shipping. I'll pay my transfer fee and insurance. Just shipped another rifle, it was only $28 via fedex. Its ridiculous sometimes when you add up what goes into these things, retail on all these parts is $1480.00.