I changed my 365 trigger to a curved one. When I got the FCU back together, the gun will not cock and fire. Does it need a mag in it to fire? What else could I have done? Thanks.

Other than some silly answer like, “You put it together wrong,” I cannot offer anything about why it’s not working.

As for firing without the magazine in, yes, it should fire without a magazine.

Make sure the takedown safety lever is properly installed.

It's the long, flat part on the left side of the FCU.

That little bugger likes to shift out of position, and while the FCU will still go back into the grip module the gun won't fire.

This message has been edited. Last edited by: rmfnla,