Nice brace, but with some minor fixable issues - SB Tactical HB AR Rifle Brace

Neither the SB Tactical website, nor the product description here on the OP website, explain what was meant by "works on mil-spec lowers only". My lower is an Aero Precision M4E1 Pro (not totally mil-spec), but I figured I'd give it a shot anyway since this was the only brace I was interested in for my pistol build. If you want to find out for yourself, this is what I had to do to make it work. (1) There turned out to be about 1/8" to 1/4" interference on the right side of the receiver where the M4E1's ambi bolt stop/release button prevented the sliding brace support bar form coming all the way forward, holding the back end of the brace about 1/8" away from being able to fully close. I trimmed the forward end of that bar to clear the ambi controls and copied the original profile angle onto the end of the rod so the controls were not blocked by the rod end. My plan was to just cold blue the raw metal area of the rod, but the metal will not take the bluing, so I'll have to paint it. It's a relatively easy job to do, but now I'm left with a shiny end on the rod that sticks out like a sore thumb. (2) The is some relatively minor sharp plastic casting flash and casting sprue material residue on top of, and under, the cheek weld part that slips over the buffer tube. I still need to smooth those areas out by scraping and/or sanding to make sure they won't cut me during use. ** Overall I still like this brace, but do wish it had the spring open assist like is on the SBPDW brace.