Yes. That lower was form 1’d a long time ago. I have four sbr’d ar15 lowers. Two 5.56s, one 300blk and one 6.5 Grendel.
This was the 7.5 when it was a pistol. Yes it was loud and obnoxious. I’ve got the Sandman-K on it now and will test it whenever we get some down time at work. Nice to have a range in the basement.
I actually don’t own any 16” 5.56 rifles (just sold my Tavor X95) so I will switch the flag lower over to a rifle stock and build a midlength gas 5.56.