Those QC10 Glock lowers are nicely made. What has your experience been with the last round bolt hold open reliability with the stock Magpul mags?
My lower is one of the early ones and the last round hold open doesn't work at all, QC 10 has since redesign the the last round hold open bar that has solved the problem, but I used to it now and just haven't bother to get the new part.