Just about any brand will fit, and all will be tight initially. Probably not as tight as you described, but tight nonetheless. We fit the uppersand lowers in complete rifles, but can't do it in seperate receivers and upper and lower halves. Generally a little TLC with a mallet is required to seat the upper into the lower (tap it together as far as it "wants to go",then pop it apart. Apply a little lube, then repeat the process. Aftre a few efforts in that manner, the upper and lower should seat together. After a couple hundred rounds, it will be as loose as it's ever goign to get, which is still tighter than an awful lot of new (prior to their loosening up) rifles out there.
I've put multiple brand combination of upper and lower together with ours and haven't had significant issuse with one brand or another. Occasionally tolerance stacking will be an issue with a particular pair of components (when one is at the top end of the tolerance and the other at the low end of it) creating either a looser or tighter fit than "normal", which may be what you encountered.
Steve/RRA