There could be a couple of issues. With any new mag, make sure the orings are all new or in new condition. A sticky oring could cause your issues.
Check the spacing from the back of the trigger to the front of the trigger rod. Air up the gun. When you turn the safety on and hold the trigger against it, there should be a tiny gap. If there isn't a gap, then you are probably choking off the air supply.
An autoresponse trigger is fairly stiff because of the double action and the installed spring that you are working against. You can reduce the full force by installing a retro on-off assembly, as mentioned by Nobody.
Except for the Automag in front, its usually the man behind the equipment that counts.