I finally got off my butt and slapped this combo together (seen with its two new friends, my HK USC 45 on a form 1 SBR and my new Marlin 1894 SBL in .44 magnum):
BCM lower with A5 receiver extension
Daniel Defense V7 upper (15” MLOK handguard, 16” CHF govt profile barrel, mid-length gas system)
Surefire SFCT FH (https://www.surefire.com/sfct-556-closed-tine-flash-hider.html)
Surefire SOCOM RC2 556 suppressor
Geissele SCH
I plan on shooting this both suppressed and unsuppressed. Shooting the rifle unsuppressed with a standard VLTOR A5H0 buffer, I felt there was little if any difference between this rifle and my Knight’s SR-15 Mod 2. In fact, I feel sort of stupid for even buying the Knight’s, especially after I bought the Bravo Company lower on sale the month before. I just “had to have a Knight’s”, but the final verdict will be when the QDC 556 can gets out of NFA jail.
Anyhow, shooting suppressed, the A5 build definitely needed a slightly heavier buffer. I bought a HeavyBuffer from Slash awhile back when I was planning this build. Today, because I was pressed for time and with my friends, I put the 4.5 oz set up in the gun, and I noticed it cycled smoother. Ejections were consistently 2-4 o’clock. No malfunctions either suppressed or unsuppressed. My friends like it as well.
I think I may make the Knight’s SR-15 a NFA item and submit a form 1 for a 11.5” build. I’ll wait for the QDC can first. Thoughts? If it weren’t for my job and two young kids, I would be taking this rifle to a carbine class this summer. I desperately need to shoot more and take another Gunsite or LAV class.
Edited to add: POI shift was at best 2 MOA from what I could tell at 100 yards. Ammo used was 77 grain SMKs and mostly M855 (IMI, PMC and NATO Danish surplus). Also, I suspect the smoother cycling with the Heavy Buffer was more due to the Wolff XP rifle spring used, rather than an ounce more weight.