Purchased a Lage 10/45 MAX upper. I attached it to my Powder Springs M10 lower and inserted a mag with a couple A-ZOOM snap caps to function test. I press the trigger, bolt goes forward and a  dummy round strips from the mag and chambers. I try to hand cycle to eject but the bolt will not budge. I lightly tap the charging handle until the extractor slips off the rim and open the bolt. Dummy round is stuck in the chamber and requires a brass rod to tap it out. I run a couple patches through and inspect the chamber and bore with a light. All looks good. Using a DiFFERENT snap cap, I press the trigger and again the bolt goes forward, picks-up the dummy and chambers it. I then try to cycle the bolt to eject and like before the snap cap is stuck in the chamber. I lightly tap the charging handle and slip the ejector off the rim, open the bolt and try to tap out the dummy round. This time it is really stuck. I remove the upper, remove the bolt and I cannot get the stuck dummy round to budge. I am hesitant to use more force.

Even if i do get the stuck dummy round out, I am not sure I want to load this upper with live ammunition.

FWIW- These are the same snap caps I have used with the factory MAC 10/45 upper and a TSMG with no issues when cycling by hand for a function test.

Any thoughts?

Load a dummy up. Brass and bullet but no primer and projectile. Try with that.

Does a loaded round drop into the chamber and fall out by hand?

I'd say give it a try with live ammo on the range and see what happens.

My Lage Upper on my Powder Springs MAC-10 45 runs great.  Its 9mm upper and I use a 9mm mag well adapter.

I just needed a brass rod with a greater diameter (closer to the bore diameter) and a bigger hammer. I also squirted some KROIL into the mix and let it sit overnight. It popped out on the first good smack.

Upon examination, it looks like the area of the snap cap that represents the case mouth got jammed into the bore.

Shout out to Lage I contacted them and they responded with insight, a recommendation and an offer to help if I needed it.

Once removed, I cleaned the chamber and bore. Live rounds of ammunition from various manufacturers drop fully into the chamber and fall out on their own when inverted.

Hopefully, I’ll get a chance to fire it soon.