Bear Creek Arsenal is having a crazy sale right now. I just picked up a 20” side-charging upper for $250.
I recall Palmetto State Armory having sales around Christmas selling build kits for crazy cheap. I’m looking for an LPK, buffer tube, and stock. Any places selling them cheap now?
AR10s can be tricky, as sizing of components is much less - well, not 'regulated' but, not as traditionally standardized as with AR15s.
if you get a complete build from a certain brand - upper, lower, barrel, bolt - then most likely the chamber dimensions and overall tolerances will all be good.
if you will try to skinflint and make an ultimate mongrel - you need to pay extra attention of how it will be working together.
stick with aero - and you will have no grief to deal with and do not need to worry about headspace gauges etc.
BCA stuff is great when it is made well, but, it can be very inconsistent. same old 80/20 % rule - if you will be in happy 80% - you will never have to complain about BCA, but get into a 20% - and you will have fun. with aero it is at least 95% or more of a 'happy'.
ps. their side charging uppers conceptually, well, i did not want to talk about that, but i would highly recommend using it ONLY for 22lr builds and keep regular builds on stock form factor.