There is a debate going on over on another forum about the anti walk pins. I read somewhere that 9mm builds have broken hammer pins in the past and stated that I plan on using the anti walk pins when I finish my build just for that reason. The second generation KNS anti walk pins are made from stainless and are supposed to be stronger over the stock pins. Has anyone here ever broken a hammer pin on one of their pistol caliber builds?

I've broke 2 hammer pins. unramped Colt style 9mm bolts, DPMS hammers. First hammer pin was a DPMS, the second was a BM.  Both broke at the center groove for the J spring. I switched to the new style KNS pins and have'nt broke them yet.

i broke mine within the first 400rds, i got some KNS pins and got my bolt ramped, runs 100% now, you def. need to get the bolt ramped, otherwise it's gonna slam the crap out of the hammer (how mine broke)

edit i should also add i'm using a DPMS hammer and my first broke pin was also a DPMS, not their fault, it was from the un ramped bolt

I broke a hammer after about 800 rds of 9mm.  The hammer pin broke in the middle.  I am running an unramped bolt and an M16 hammer with the tail bobbed.  I installed a set of KNS 2nd generation anti-rotation pins and have gone through about 1000 more rds without a problem.

G

I have to maintain about a metric assload of Colt SMG's deployed all over the world.

The issues that I have with them are:

Broken Hammer Pins
Dimpled Dissconnectors, and weak dissconnector springs
loose roll pins in the rear of the bolt
barrels comming unscrewed

Quoted: I have to maintain about a metric assload of Colt SMG's deployed all over the world. The issues that I have with them are: Broken Hammer Pins Dimpled Dissconnectors, and weak dissconnector springs loose roll pins in the rear of the bolt barrels comming unscrewed

No kidding. The barrels come unscrewed because there is no gas tube keeping the barrel nut from backing out?

Quoted: Quoted: I have to maintain about a metric assload of Colt SMG's deployed all over the world. The issues that I have with them are: Broken Hammer Pins Dimpled Dissconnectors, and weak dissconnector springs loose roll pins in the rear of the bolt barrels comming unscrewed No kidding. The barrels come unscrewed because there is no gas tube keeping the barrel nut from backing out?

Yep, I have in the past put a piece of round stock to keep everything from comming undone.

Broke the hammerpin in my RRA 9mm last outing to the range.  I've put about  4k rounds through it since I built it.  DPMS hammer, unramped bolt.  

I had spare pins, but they were at home (D'Oh!).  I got some JP pins at the range, put them in my 5.56, and put one of the pins from it in the 9mm to get it up and running again.

I'm planning on having my bolt ramped, getting KNS pins for my 5.56, and putting the JP pins in the 9mm as soon as I have money.

It would seem that using an un-ramped carrier in a 9mm AR = a broken hammer pin sooner or later.  The ramp on the carrier slows down the cocking stroke of the hammer to a more reasonable speed, progressively depressing the hammer as the carrier moves rearward.  Without the ramp, the hammer gets slammed back as soon as the carrier begins to move rearward, leading to the broken hammer pins.

Another aspect of this situation besides the obvious broken hammer pins is the extreme hammering that your lower receiver's hammer pin holes receive from using an unramped carrier.  If the pin is getting whacked hard enough to break it, you've gotta figure that the holes are taking an extraordinary beating as well!  Yet another would be the receiver damage resulting from the broken hammer pin "wallowing and gouging around" in the receiver, after it gets that fatal hit which breaks it.  

If you look at any 5.56mm AR-15/M-16 bolt carrier, shrouded or unshrouded, you will notice it is ramped, and this is so for good reason.  It seems like the person who designed the unramped 9mm carrier was asleep at the wheel, or didn't have a very good grasp of physics.

Quoted: Another aspect of this situation besides the obvious broken hammer pins is the extreme hammering that your lower receiver's hammer pin holes receive from using an unramped carrier.  If the pin is getting whacked hard enough to break it, you've gotta figure that the holes are taking an extraordinary beating as well!  Yet another would be the receiver damage resulting from the broken hammer pin "wallowing and gouging around" in the receiver, after it gets that fatal hit which breaks it.

+1

Broken hammer pin = pita

Egged out hole in lower = major pita

I broke one in my dedicated .22... Broke in half, but both pieces stayed in. Took me two range sessions to figure why it wasn't runnin well.