AERO PRECISION - M4E1 ENHANCED 5.56 NATO ASSEMBLED UPPER RECEIVER FOR AR-15

My second time purchasing this upper and very happy with it. No issues with running it on my first set up, currently in the middle of my second build which is why I purchased this one. Fits perfectly with my Aero Lower, and very easy installation of an Enhanced handguard.

I run these whenever I can. No barrel shims required. True free floating concept in that the hand guard bolts to the upper, not the barrel nut. A sold piece of industrial engineering that will last a lifetime. And during these times, rare as gold.

I purchased this upper for my first build. A friend of mine talked me into buying the enhanced upper instead of a stripped upper. I am glad that I took his advice. I have watched many experienced builders trying to time their uppers and have to torque, loosen, torque again, loosed... you get the idea. This was so much easier. Barrel installation was very easy. The gas block and tube lined up with no trouble at all. I changed the ejection port cover and forward assist; both were easily switched out. I couldn't be happier with this upper. I plan on purchasing an enhanced M5 upper for a future build.

This is a quality upper and the ease of a build where you don't have to "worry" about clocking the barrel nut to line up the gas tube will be a big plus to the first time builder (the upper also comes with the barrel nut as well as the proprietary wrench) so all that is needed a 1/2" torque wrench, proper application of lube to the barrel nut and an upper vice block to secure the upper...just making sure that the torque is correct and you are good to go...that gas tube will be right where it needs to be... Finish is good...good anodizing...no imperfections...It really has the look of a billet upper (if that matters)... But the ease of the barrel installation and the overall quality are big pluses (especially for a new builder) as well as the "one piece" feel between the upper and hand-guard being another... I have been very well pleased with this upper as well as well as other AERO products.

I purchased this upper to make an Adams Arms XLP piston conversion work. I'm using with an 8.2" CMMG Barreled .300 blackout, with 12" Aero railed handguard, for a suppressor "under the handguard" build . The XLP piston kit gas block fits under most handguards, BUT requires a mil-spec barrel nut "length" in order for the drive rod to work. That makes it incompatible with most handguards that don't utilize a mil-spec barrel nut. ENTER THE ENHANCED UPPER! Aero says it's not compatible with pistons, but it is.....if you purchase a 3/8" diameter piloted counterbore with 3/16" pilot (buy online for about $30 delivered), you can very easily use the gas tube hole in this upper to pilot the counterbore and bore a recess through the first and second gas tube hole "fin", coming to rest on the face of the 3rd fin, (to yield a length equal to mil-spec barrel nut length). That recess will accept/capture the drive-rod bushing that captures the spring on the piston drive rod. You just have to take the bushing to a grinder and grind a small crescent of material off of one side of the bushing to make it clear the barrel nut, and.... PRESTO! you've got a rock-solid piston converted upper. Plenty of barrel nut threads left to not lessen reliable barrel torque, & no alteration to the barrel nut at all. This upper is completely solid and almost monolithically rigid when coupled with an Aero enhanced handguard. I like that I can remove it easily with the screws to maintenance the piston and suppressor if needed, since the large diameter of the hand guard will slide over everything. I bought it with the 12" railed hand guard so that a 1.5" suppressor will fit inside with lots of clearance to spare. I think this is a perfect solution to what I found to be a huge problem. (It saved me from giving up and returning my XLP kit!) I'll be purchasing a couple more of these uppers for use in precision rifle builds too, as I think they offer more rigidity to the barrel lock-up area, since there is a LOT more material than on a standard upper, to dampen harmonics and add rigidity to heavy/long barreled builds.