Finally received the barrel last week, checked the headspace and installed it on the upper, along with the gas block, handguard, and muzzle devices. Finally got to take it out for a spin yesterday and get the gas block adjusted, worked great. Finished torquing everything down today and applying loctite where required.
Other than awkwardness installing the barrel nut because of my small vice and limited workspace, there was no drama finishing the upper. I polished the inside of the gas block and outside of barrel where they meet with moly powder, it made installing it a breeze.
Here is the component list for the upper:
**upper
Aero Precision M4E1, black
**handguard
Aero Precision 9" MLOK
**dust cover
Strike Industries enhanced UDC, black polymer
**forward assist
Stock upper part
**charging handle
Radian Raptor LT
**bolt carrier
Superlative Arms
Ionbond DLC black coating
H-13 tool steel op rod
**bolt
LMT Enhanced Bolt
**cam pin
POF Roller Cam Pin
NP3 coated
**firing pin
V Seven Weapon Systems
Grade 23 Titanium, Ionbond DLC black coating
**firing pin retaining pin
KNS Precision Perma Pin
**buffer
JP Silent Captured Spring
std weight, std spring
**buffer retainer
V Seven Weapon Systems
Grade 5 Titanium
**buffer retainer spring
Neverwear Inconel 600
**barrel
Andro Corp 10.5" 5.56 1/7"
41V50 steel, salt bath nitride finish
**gas block
Superlative Arms Piston Block, clamp type
416 stainless steel, salt bath nitride finish
**muzzle devices
Precision Armament EFAB
Indian Creek Design BFD
1mil shim washers, 18-8 stainless steel
It took about 20 rounds to get the gas block adjusted and get optimal settings for the 5 different types of ammo I brought with me, all the 5.56 ammo seemed to have the same setting of 7.0 where the bolt failed to lock back, except for Hornady Black 62gr, which did lock back on 7.0. 7.0 on the gas block is turns from 0 (no gas), where 4.5 is fully open, and numbers above that bleed out the front of the block. The .223 required a quarter turn more gas, as expected. With final settings of 6.5 for 5.56 and 6.25 for 223, the recoil impulse was very low and soft. An additional 11 mixed rounds in 3 mags were shot after testing with the BFD was reinstalled to make sure it all worked correctly and to see how it did its job, which was quite well.
Upon inspection and cleaning, the only thing that was dirty was the bolt face and the chamber, the piston kit keeps the rest of it extremely clean. Aero had a note about their upper NOT being piston kit compatible, but others have run the Superlative kit with success, as did I. The machining on the gas block and bolt carrier is of the highest quality, and the op rod fits perfectly through the unusual gas tube hole in the upper. I added a rail cover over that area, that is where I added lube for the op rod and dont wait it spraying onto an optic. The op rod is H-13 tool steel, which is similar to 41V40 CMV, but has 5 times the chromium, molybdenum, and silicon, with about half the manganese. It is very strong and rigid.
I may add a bolt spring or change the forward assist at some point in the future, but it is ready to go now. After I throw some sort of sight on it I will shoot a few full mags and look for signs of abnormal wear in the BCG area. With a 10.5" barrel I am not expecting huge accuracy, 4moa will make me happy, the optics I have available to me at the moment will not be good enough for that, so I will pick up a 1-6x scope more than likely.
I will get some pictures and come up with a $ figure, which was more than I was expecting, but is still a lot less than a piston driven AR from HK or LMT, with a superior trigger, almost all stainless/rustproof components, and I fully trust the build work because I did it.
