i installed a two stage rra trigger in my ar10a4,the problem i am having is that the hammer is not locking back after each shot.someone told me that it is shortstroking but the next round is being chambered, my ammo is handloaded and was working just fine with the factory fcg.i called rra and they said that they dont know the cause and to send them the trigger. thanks for any help

Chances are that the disconnector is not retaining the hammer at cock, and the hammer is following the carrier back down when the carrier closes.

Best bet is to pull the trigger group and see if you have crap under the back hook of the trigger (disconnector). Also, you may want to check the disconnector spring, you may have left it out when you installed the FCG.

thanks dano ,the hook is clean and the disconnector spring is in place, any more suggestions

Take the upper and lower apart.  With the hammer down, pull the trigger all the way back and hold it there.  Now cock the hammer all the way back.  When you encounter the disconnetor there will be considerable resistance.  If the disconnector will not hold the hammer back, you need to look closely at the disconnector and make sure that it is moving freely and can engage the hook on the hammer.  It is possible that the tolerances on the hammer and trigger pin hole placements are such that surfaces are nt properly mated.  Does an AR10 have the same pin hole placement as an AR15?