View Full Version : Broken Trigger Pin
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I received a Giessele G2S today so I was swapping out a trigger from one build to the next. I was taking out a stock trigger from a Rainier Arms build and putting in an ACT as the G2S was taking its spot of the ACT in another build. As I pushed out the original stock trigger pin I noticed it fell right out. As I looked at it, I noticed it was only half the pin. The other half was still inside. After pushing that part out I took a pic. It appears the trigger pin snapped in half right at the center detent.
Has anyone had this happen before?
Weapon still functioned normal. I shot about 100 rnds last week and many more in January. I have no clue when / how this occurred.
Looks like I need to pick up a trigger pin.
bleaman225
02-20-13, 23:16
I've never seen that personally.
Just curious, when you say
I was taking out a stock trigger from a Rainier Arms build...
Does this mean you built the gun with parts from Rainier or they built the gun themselves? Maybe before this thread has a chance to head too far south, you should contact RA...
Since its such a small piece I'm not worried about it. Their CS is top notch and I will continue to do business with them.
I've got extra pins so I don't need one.
This thread was created in order to see if anyone has experienced something like this before. I've never seen it so I was curious.
I debated about putting the name in here but I figured I'd have multiple posts asking who made it etc. This is not a complaint of their quality as I've owned this lower since 2011 and its been through its paces with out one issue. While I did contact them first, I am not worried about getting a reply. They have probably a thousand orders waiting to ship. My $2 pin isn't a big deal.
I'm not sure if it was my fault. Essentially, by slowly pushing the pin out, the tension the trigger spring created may have caused it to snap or it could have been tension from me. Or it was just a faulty pin? This pin could have been broken for a long time, since I haven't removed the trigger since back in Sept / Oct.
But - the weapon has been flawless so I'm definitely confused as to how it occurred.
There is nothing that you can do installing or removing the hammer/trigger pins that would cause that, unless you demonstrated catastrophically poor technique on removal. It was a bad pin.
9mm guns are really hard on pins, but I've never had a 5.56 pin break.
Ned Christiansen
02-21-13, 09:31
I've seen them break.
Some AR's have a condition where on the backstroke, the disconnector runs out of free travel as it is being cammed back by the hammer. It moves the rest of the way by "picking up" the trigger and moving the trigger with it, against the tension of your finger. I've always figured these guns were candidates from broken pins. Oddly enough I haven't seen one that gave a trigger slapping sensation when firing-- seems like it would-- but you can feel it in hand cycling, the slight forward motion on the trigger.
Seems like there are good pins and bad pins, too.
At a class last weekend I had just finished telling the class that hammer and trigger pins are the same, interchangeable, can go in from either side and with the outboard groove on either side.....when a student brought up his hammer and trigger pins. They weren't interchangeable. One had an outboard groove and no central groove. One had a central groove and no outboard groove.
Me no understand.
I've replaced at least three of those pins in friends and coworkers guns over the years.
It's all a solid foundation of why I always keep spare parts on hand like that.
Is there any way you can get a clearer picture of the fracture surface?
ohiorifleman
02-21-13, 12:14
I replaced one that broke in the same spot on a build done with a 380.00 complete parts kit that was bought at Knob Creek in the late 90s. Nothing in that kit was good- and I warned the owner never to grace my workbench with that "unknown" junk again.
This was as good as I could get it with my crappy camera and limited skills.
http://img5.imageshack.us/img5/33/brokenpin3.jpg
Hard to tell with that picture but it was probably a flaw in the material. I'm not seeing any features that indicate any particular failure mode, fatigue or otherwise...
My last try. But yes, it seems like it's just an issue w/ the metal as opposed to any pressure or fatigue.
http://img19.imageshack.us/img19/9457/brokenpin4.jpg
Ned Christiansen
02-23-13, 14:31
They all look like that.
They all look like that.
I'm not understanding what you're talking about.
They all look like that when they break?
Rattlehead
02-23-13, 18:34
I've had this happen as well.
Ned Christiansen
02-23-13, 19:27
Sorry, yes-- the ones I've seen had the same appearance at the break.
I've seen a couple do this at the store. Sometimes a bad pin, sometimes overgassed/underbuffered so the bolt group is slamming back too hard and beating on the disconnector. The trigget pin (and receiver) take the force.
I'm attributing it to a bad pin.
I run a 14.5" midlength with a H2. I would assume it's not a gas issue but I've been wrong before and I'm sure I'll be wrong again in the future.
Thanks for the replies guys. I've got some pins coming in the mail.
Broken trigger pins are common with pistol caliber Ar's . We broke a few when we issued 9mm Colt Sporters and sub guns
Broken trigger pins are common with pistol caliber Ar's . We broke a few when we issued 9mm Colt Sporters and sub guns
My experience is the same. Colt SMGs seem to beat the hell out of hammer and trigger pins.
I had the same issue with a BCM 16" mid-length that was purchased complete. On my second trip to the range the trigger became extremely gritty (understatement of the year). I racked the rifle and finished the night with another. Upon inspection at home my pin looked like the above photo. A call to BCM had another set of pins on the way and a couple of caps, the next day. Excellent customer service from BCM!
However, the trigger never had an acceptable feeling afterwards. Thank goodness for Geiselle.....
Suwannee Tim
02-25-13, 19:02
There are a number of reasons why a pin might fail and you really can't tell by looking. To get a definitive answer on the reason for the failure it would have to be examined by people with specialized knowledge and access to specialized equipment i.e. a metallographic examination.
My last try. But yes, it seems like it's just an issue w/ the metal as opposed to any pressure or fatigue.
http://img19.imageshack.us/img19/9457/brokenpin4.jpg looking at that picture a bit of over cooked steel http://books.google.com/books?id=hoM8VJHTt24C&pg=PA71&lpg=PA71&dq=microstructure+of+overheated+steel&source=bl&ots=MjUCfO5hjw&sig=VVcjGNs-sL3-BVwSFY4V374otWY&hl=en&sa=X&ei=QD0sUb_JDYyq0AHv34DoCQ&ved=0CEMQ6AEwAg#v=onepage&q=microstructure%20of%20overheated%20steel&f=false
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