Decent, could be better. - JP Enterprises LTC-19 Billet Stripped Upper Receiver

I bought this for the thermo fit, I like the idea of a super tight barrel joint. Fit and finish is fine, as you would expect for the price. It’s extra chunky in places which made for a strange fit to my Aero pattern lower. There is also a big gap at the back of where the upper and lower meet. I knew poor fit was a possibility since this kind of thing is pretty typical for large frame AR. It isn’t worth returning but what I’m most disappointed in is JP doesn’t appear to sell lowers by themselves. Why sell uppers but ONLY sell lowers as a matched set? Since I already have the upper and it fits poorly I would like to buy a lower but I don’t need matched set.