Works good - Stern Defense AR-15 10 inch Assembled Upper Receiver, 8.5 in 9mm Barrel w/MLOK Rail

Works good, good finish with no sharp edges. The hexagonal blast can was oriented in a way that at the 6oclock forward most mlok slot the nut hit the muzzle device underneath the handguard, no issue as the blast can wasn't too tight like some ive replaced brand new. The flats on the muzzle device do allow space for the nut when oriented correctly. Side note, whoever installed that muzzle device originally had it clocked perfect. That little detail says alot about the assembly process it went through and even the manufacturing. After the lady gifted it to the man and he shot it function check I took apart some screws to check for loctite, i didnt notice any so when assembling I used a little bit. It is a very good upper, I am impressed. I was asked by a lady to help surprise her husband with one after she found out he was trying to purchase my full weapon, im regretting it because this thing is a laser, its beautifully machined too. I coulda just got me one of these after that. I chose endomags to be able to keep an ar15 lower so he can get different uppers if he choses bc this was his first ar platform and i know after i got mine I wanted different upper which turned to different lowers and so it goes so that option is still there for him. I've had great experiences with endomags especially for the purpose of being able to have the option to use other caliber uppers. Fitting can be bothersome but after that it works fine. The groups this made after zero were 4 inches by him, I did shoot it a few times but never focused for groups as i was confirming its fluid operation. Used a 6oz buffer, for those who are curious. I really appreciate this product and he loved it too. I fully recommend this product, and what sold me on this was the iv8888 video of their meltdown on YouTube. Lasted over 6k rounds running full auto using their magblock adapter, Im fully sold with Stern Defense and had to write a review for this because there are no others at this time and I was fully impressed with the product. I was confident enough to put this together for somebody else, now I'm jealous of it.