AR hammer pin drifting out

mofosheee · February 1, 2024, 06:00 PM

Hello Firing line

Recently purchased a new lower.........assembled with a new parts kit without issue to include a Geiselle trigger. Ran two mags without issue except that the the hammer pin had illegally migrated out of the left side of the receiver, approx 0.125"

Reviewed the Midway and Brownells online tutorials to confirm proper assembly and searched the forum for a solution. I'm not understanding the errors in my assembly and prefer not to install an anti walk kit.

Please advise.
Thanks

davidsog · February 1, 2024, 06:21 PM

Contact Geiselle. You are not the first one to have this issue. Their customer support can send you oversized pins for your model trigger.

https://geissele.com/contact

tangolima · February 1, 2024, 07:20 PM

The hammer has a detent to engage a groove in the middle of the hammer pin to keep the pin from walking out. On top of that the hammer spring puts load on the pin. These two put together, the pin should stay put, at least so for the milspec (cheap) ARs.

-TL

Sent from my SM-N960U using Tapatalk

50 shooter · February 2, 2024, 05:26 PM

You can always upgrade to an anti walk pin set for your lower.

https://www.primaryarms.com/ar-15/lo...s/trigger-pins

Shadow9mm · February 2, 2024, 08:01 PM

Quote:

Originally Posted by tangolima

The hammer has a detent to engage a groove in the middle of the hammer pin to keep the pin from walking out. On top of that the hammer spring puts load on the pin. These two put together, the pin should stay put, at least so for the milspec (cheap) ARs.

-TL

Sent from my SM-N960U using Tapatalk

Exactly. There is a little spring in the hammer that is supposed to lock into the groove in the center of the pin to keep it in place. Id verify that its installed correctly, kinda snaps into place, shoot it again to confirm the problem. If it walks again call the Manufacturer. If it does not you solved the problem.

rickyrick · February 4, 2024, 12:04 AM

I haven’t heard of or experienced this except in cassette type triggers, and for that matter, I’ve only read about this happening in cassette type triggers.

I do have one lower with anti-walk pins, but they cam as a bonus with the trigger.

davidsog · February 4, 2024, 08:09 AM

Quote:

I haven’t heard of or experienced this except in cassette type triggers, and for that matter, I’ve only read about this happening in cassette type triggers.

Exactly. That is why Geiselle says to contact customer service and why they have multiple pin sizes available.

Sharkbite · February 4, 2024, 09:36 PM

With ANY cassette type AR trigger, i always install anti-walk pins. With a “mil-spec trigger” one leg of a spring holds the pin in place.

Cassette= Anti-walk pins……sorry.

Nathan · February 5, 2024, 05:36 PM

https://www.brownells.com/gun-parts/...nti-walk-pins/

My favorite type.

Destructo6 · February 6, 2024, 08:17 AM

No word back from the OP?

In mil-spec triggers (I know this is similar, but not exactly the same), I've never seen a hammer pin walk, but have seen a few trigger pins walk if the hammer spring was installed improperly.

February 1, 2024, 06:00 PM	#1
mofosheee Junior Member Join Date: October 22, 2018 Posts: 8	AR hammer pin drifting out Hello Firing line Recently purchased a new lower.........assembled with a new parts kit without issue to include a Geiselle trigger. Ran two mags without issue except that the the hammer pin had illegally migrated out of the left side of the receiver, approx 0.125" Reviewed the Midway and Brownells online tutorials to confirm proper assembly and searched the forum for a solution. I'm not understanding the errors in my assembly and prefer not to install an anti walk kit. Please advise. Thanks

February 2, 2024, 05:26 PM	#4
50 shooter Senior Member Join Date: August 6, 2002 Location: SoCal PRK Posts: 986	You can always upgrade to an anti walk pin set for your lower. https://www.primaryarms.com/ar-15/lo...s/trigger-pins __________________ I see the world thru bloodshot eyes Streets filled with blood from distant lies The dogs of war never compromise, No time for rearranging.

February 4, 2024, 12:04 AM	#6
rickyrick Senior Member Join Date: March 15, 2010 Posts: 8,238	I haven’t heard of or experienced this except in cassette type triggers, and for that matter, I’ve only read about this happening in cassette type triggers. I do have one lower with anti-walk pins, but they cam as a bonus with the trigger. __________________ Woohoo, I’m back In Texas!!!

February 6, 2024, 08:17 AM	#10
Destructo6 Senior Member Join Date: March 18, 1999 Location: Nogales, AZ USA Posts: 4,001	No word back from the OP? In mil-spec triggers (I know this is similar, but not exactly the same), I've never seen a hammer pin walk, but have seen a few trigger pins walk if the hammer spring was installed improperly. __________________ God gave you a soul. Your parents, a body. Your country, a rifle. Keep all of them clean.

February 1, 2024, 06:21 PM	#2
davidsog Senior Member Join Date: January 13, 2018 Posts: 1,328	Contact Geiselle. You are not the first one to have this issue. Their customer support can send you oversized pins for your model trigger. https://geissele.com/contact

February 1, 2024, 07:20 PM	#3
tangolima Senior Member Join Date: September 28, 2013 Posts: 3,829	The hammer has a detent to engage a groove in the middle of the hammer pin to keep the pin from walking out. On top of that the hammer spring puts load on the pin. These two put together, the pin should stay put, at least so for the milspec (cheap) ARs. -TL Sent from my SM-N960U using Tapatalk

February 4, 2024, 09:36 PM	#8
Sharkbite Senior Member Join Date: November 4, 2013 Location: Western slope of Colorado Posts: 3,679	With ANY cassette type AR trigger, i always install anti-walk pins. With a “mil-spec trigger” one leg of a spring holds the pin in place. Cassette= Anti-walk pins……sorry.

February 5, 2024, 05:36 PM	#9
Nathan Senior Member Join Date: July 1, 2001 Posts: 6,334	https://www.brownells.com/gun-parts/...nti-walk-pins/ My favorite type.