AR trigger pin walks

pslater · February 27, 2013, 10:11 PM

I replaced the stock trigger on my Daniel Defense M4 with a Geissele Super Dynamic -Enhanced trigger from Midway. I love the trigger but after firing a few rounds, the trigger pin (not the hammer pin) starts 'walking' out of the left side of the receiver and will eventually (20 rounds or so) cause the trigger to jam.

It's my understanding that both the hammer and trigger pins are inserted from the right side of the receiver with the 'double grooves' end of the pins going in first. According to the instructions I have, the feet of the trigger spring go in and rest on the bottom of the receiver (right?). The feet of the hammer spring rest in the grooves of the hammer pin so, what holds the trigger pin in place?

Any help will be greatly appreciated as my messages to Geissele get replied to with 'take it to a qualified gunsmith'.

BBBBill · February 27, 2013, 10:45 PM

Ensure your hammer spring is installed correctly. The legs of that spring rest in grooves on either side of the trigger pin. The trigger pin is held in by the hammer spring legs resting on top of the hammer pin in the groove. Check the trigger to make sure that the sides of the trigger are not blocking the grooves. Stone the sides to give the spring legs room to fit if needed. if the grooves are too shallow, either file them deeper or replace the pin.

The J-spring in the hammer holds in the hammer pin.

DoubleTapDrew · February 28, 2013, 05:12 PM

Had that happen to me. The previous owner had put the legs resting on the bottom of the receiver rather on the grooves in the pin so it would work itself out after about a mag-full.

Kp321 · March 1, 2013, 10:46 PM

+1 on checking for proper spring placement. If you continue to have problems, Brownells and others sell anti-walk pins. They are longer and have E-clips on each end.

xfyrfiter · March 2, 2013, 04:54 PM

Your instructions are wrong, post #2 and the pic in post #3 are right.

pslater · May 4, 2013, 09:02 PM

Gentlemen,

Thanks so much for your input. Stoning the trigger fixed the problem as the hammer spring leg was getting hung up between the trigger and the receiver and not reaching the pin. All is good now, several hundred rounds through the rifle after the fix and no pin walking.

Thank you again!

February 27, 2013, 10:11 PM	#1
pslater Member Join Date: November 29, 2011 Posts: 7	AR trigger pin walks I replaced the stock trigger on my Daniel Defense M4 with a Geissele Super Dynamic -Enhanced trigger from Midway. I love the trigger but after firing a few rounds, the trigger pin (not the hammer pin) starts 'walking' out of the left side of the receiver and will eventually (20 rounds or so) cause the trigger to jam. It's my understanding that both the hammer and trigger pins are inserted from the right side of the receiver with the 'double grooves' end of the pins going in first. According to the instructions I have, the feet of the trigger spring go in and rest on the bottom of the receiver (right?). The feet of the hammer spring rest in the grooves of the hammer pin so, what holds the trigger pin in place? Any help will be greatly appreciated as my messages to Geissele get replied to with 'take it to a qualified gunsmith'.

March 2, 2013, 04:54 PM	#5
xfyrfiter Member Join Date: March 17, 2010 Location: NW New Mexico Posts: 605	Your instructions are wrong, post #2 and the pic in post #3 are right. __________________ I carry a gun, because a cop is just too darned heavy, and hard to feed.

May 4, 2013, 09:02 PM	#6
pslater Member Join Date: November 29, 2011 Posts: 7	Thanks! Gentlemen, Thanks so much for your input. Stoning the trigger fixed the problem as the hammer spring leg was getting hung up between the trigger and the receiver and not reaching the pin. All is good now, several hundred rounds through the rifle after the fix and no pin walking. Thank you again!

February 27, 2013, 10:45 PM	#2
BBBBill Member Join Date: March 7, 2005 Posts: 880	Ensure your hammer spring is installed correctly. The legs of that spring rest in grooves on either side of the trigger pin. The trigger pin is held in by the hammer spring legs resting on top of the hammer pin in the groove. Check the trigger to make sure that the sides of the trigger are not blocking the grooves. Stone the sides to give the spring legs room to fit if needed. if the grooves are too shallow, either file them deeper or replace the pin. The J-spring in the hammer holds in the hammer pin.

February 28, 2013, 05:12 PM	#3
DoubleTapDrew Member Join Date: February 23, 2006 Location: Oregon Posts: 5,327	Had that happen to me. The previous owner had put the legs resting on the bottom of the receiver rather on the grooves in the pin so it would work itself out after about a mag-full. __________________ "Those who would give up Essential Liberty to purchase a little Temporary Safety, deserve neither Liberty nor Safety." - Benjamin Franklin NRA Life Member

March 1, 2013, 10:46 PM	#4
Kp321 Member Join Date: July 12, 2012 Location: West Texas Posts: 187	+1 on checking for proper spring placement. If you continue to have problems, Brownells and others sell anti-walk pins. They are longer and have E-clips on each end.