alright, my buddy was out in the shop when i got off my shift so i ran over there and assembled most of the upper. i had to get it back to my gf's dad who works 3rd shift so forgive a lack of pictures compared to the lower but I do have a few more for you guys!
clamp your upper receiver in your vise block (cheap no name one from ebay works great), the insert your barrel into the receiver noting the orientation of the key on the barrel and corresponding notch in the receiver. gentle use of rubber mallet may be required.
most of the following is for my bcm kmr rail that uses a proprietary barrel nut, reference your hardware's manufacturer for installation differences.
i used a little frog lube on the threads and slid the barrel but over the barrel down to the receiver and thread on hand tight.
torque spec is 40-50ft/lbs so i just ran down the middle at 45.
using the supplied 1/2" drive wrench (same pattern as your buffer tube castle nut wrench) torque the barrel nut on then using a breaker bar loosen again until you've torqued the nut to 40-50ft/lbs at least 3-4 times to ensure proper torque is met.
Now with your barrel nut on, slide your gas block on (in this instance a bcm low profile .625")
apply loctite to the set screw threads and install. if you use a bcm or other set screw intended barrel and a set screw gas block instead of a taper pin setup you should have at least one dimple machined into the barrel or some people find hardware comes loose. bcm is nice enough to dimple their barrels for one set screw, we'll see if the 2nd screw comes loose over time.
with the gas port and roll pin hole oriented toward the gas block, slide your gas tube into the receiver then back into the gas block.
line up the holes in the gas tube and block and insert your roll pin. don't worry this one usually goes in much easier than the stubborn ones on a build but an extra set of hands to hold the upper still helps.
NOTE: if you don't insert the tube all the way it can look like its lined up and when you send the bcg into battery the gas key can become stuck in the gas tube and you won't be able to get the bolt to lock into the barrel.
now install your muzzle device with whatever the supplied hardware/washer is according to the manufacturer's instructions. There's nothing complicated about this one, just a lantac dragon with a simple crush washer.
that's where my last minute continuation of this build ends for now. as of friday evening the upper is at the gunsmith having the brake pinned, so it's just a waiting game to hear from him that its ready for pick up. stay tuned for the post gunsmith results and bcm kmr install!
