>>63955145
Yeah, it's perfectly fine. 8/10 Upper
If you really want to clone an M4 without fooling with SBR nonsense I recommend getting this one:
>https://bravocompanyusa.com/bcm-standard-14-5-m4-socom-upper-receiver-group/
and putting pic-rel on it. Much less noticeable and you get a small benefit in flash reduction. ADCO will pin and weld it for $30