"I'm a bit skeptical that many military supplies vary dramatically"
Well, how much do you think china is paying for one of their own developed (or copied) and manufactured assaults rifles - and how much is the US?
I didn't look up the numbers now, but I am pretty sure they do vary dramatically.
The change might get less, when we are talking about very advanced war tech, like fighter missiles and radar systems, but overall China with all of its big factories and strong central controlled government - might have an edge there.