I have a MT 6700 and I'm interested in putting together another upper for it.  I don't know crap about doing it, but WTH.  What is the deal with mil-spec uppers fitting colt lowers?

Thanks

The MATCH TARGET's front pivot pin hole is the standard dimension, so no problem putting a different upper on it.  Some early MATCH TARGETS have a steel block pinned in the receiver that will not allow the upper to lock down on the lower if you use what is commonly referred to as a "M16" carrier.

Should be no problem fitting Mil-Spec uppers if you have a small pivot .250" diameter hole Mil-Spec lower.

I did it, I have a Colt M16A2 upper on a Colt Match Target H-BAR MT6601 model lower.

I don't have a sear block, just an unmachinned web common to the auto sear area above the selector.

I'm also using a Colt M16 bolt carrier.

If your lower have high sear block you could either remove it or grind it flush with the top edge of your lower so you could use a M16 carrier.

If you get an older upper like mine which was finished in Colt grey the finish don't match the black/ dark grey color of the MT models, but if you get a new model like the LE series the finish should be pretty close.


A pic of my rifle link