Need some Advice on MUR1 upper
Recently I bought a VLTOR MUR1 Upper to fit on my spikes blem lower. When I fit the MUR1 on to the spikes lower I noticed that I have a gap that you could fit about 1 or 2 index cards through for reference at the rear of the receiver around the receiver extension and just above the takedown pin. As you make your way towards the front end of the receiver the fit is great between the upper and lower. The gap is just at the rear. I understand that it probably wont cause functional issues. It is just annoying because I am a bit of a perfectionist. Should I invest in some accuwedges, I have also heard of putting an O-ring around the "takedown pin hole". Some tips would be great. Thanks.