Got the rest of the parts for my M4gery upper build.


Install the completed upper receiver into the receiver block.


Insert the receiver block into your vise. (I did all of the finish assembly/torqueing in my bench vise, but just used the kitchen table for loose assembly and photos)


Get your delta ring assembly ready and then assembly with the C-ring going on last.




Apply your chosen anti-galling agent to the threads on the receiver and insert the barrel, aligning the pin on the receiver extension into the notch.

Using the gas tube, align the gap in the delta ring so that it is top dead center. (I used a spare tube, just in case.) Tighten the barrel nut, back it off a bit, tighten again, loosen, tighten again, and align one of the notches (shown by the barrel nut wrench pin) with the gas tube. 80 ft/lbs is the torque amount I use, checked with a torque wrench.


Insert the gas tube from the receiver end, through the delta ring, and align in the front sight base. Install 5/64"x1/4" roll pin into the front sight base, securing the gas tube.


Install the crush washer, then the flash hider. Tighten as needed, using the crush washer to properly time the flash hider. (Done in the vise block.) With an A2 flash hider, the closed section is at 6 o'clock.



Install the front hand guard.



Install the charging handle and bolt carrier group.




Install rear sight systems. I run a flip up rear sight in addition to a Bushnell red dot.




6.8SPC assembly should take place Thursday. Both rifles will be checked for headspace, then test fired this weekend. Accuracy tests after that.

There are three specialized tools needed, the vise block, headspace gauges, and the barrel wrench, but after that most guys have the tools in their garage or on their workbench to be able to complete an upper.

There are a number of things I left out (Black Bart is probably cringing), so before you do it, buy a book and read up on it, talk with an experienced builder, and get to it.

More later this week.