Im having the same issue. i had an earlier version and it worked great. About 3-4 mags later it just stopped, or was sporadic in function.
Bought the latest version for a friend with the modified trigger included and figured i would try it out before handing it over. The fitment between the barrel and arm were indeed different (old was sloppy). i modified my old trigger as well. Just figured it was worn out, but No dice with new version and the supplied modified trigger, it just doesn't work at all. Bummed out.
