View Full Version : Bent Firing Pin?????
geminidglocker
12-23-09, 16:51
How did this happen? Yesterday I tested out Wolf ammo in my Bushy. 120rds. flawless. Thios reifle has 8500rds through it without a hiccup, mostly Prvi 55gr and Fed XM193. I found Wolf at a local store for 5.38 a box so I figured I'de run some and see if it was worth buying, as I have heard that sometimes the lower teir rifles will choke on it. Well, it ran fine and was quite accurate too.
Today, I tear down my rifle to see how dirty it was. It was cleaner than Fed 193, beleive it or not. I stripped it down and cleaned it. upon re-assembly, as I dropped the firing pin back in, i noticed(Looking in from the rear of the BC), that it was way off center. I then remembered that upon dissassembly, the firing pin required a bit of a tap on the rear of the BC to get it to drop out. I thought nothing of it at the time because everyone said Wolf was dirty stuff. I have a friend bringing me a new one home from the shop tonight, so the problem is as good as fixed, but I've never seen this before. Keep in mind I was in the Army, and have fired more than my share of rounds and cleaned my share of rifles aswell. So here are some pics:
http://i296.photobucket.com/albums/mm196/davecharlie08/BentFiringPin005.jpg
http://i296.photobucket.com/albums/mm196/davecharlie08/BentFiringPin006.jpg
ETA: I tried search option but found nothing.
P.S. Please no brand bashing. It's the firing pin, not the whole weapon. Oh, and the bolt is marked CM. if that means anything, it's the bolt that came with the rifle, and does'nt exhibit any damage. The rifle is the ORC model(Flat-top with front sight tower removed)
geminidglocker
12-23-09, 17:26
Bump. It's eating me up inside. I don't want to let it happen again. My instinct tells me that it is metal fatigue, and that had I fired more with it it would have eventually broke. Witch leads me to ask, where does Bushy get their Firing Pins from??? So that I don't order from them when I order a few spares to have on hand.
Never seen that before. Was the retaining pin in correctly? No problems with light primer strikes or failures? I would not think that the primer on Wolf would be so hard as to cause the pin to bend in the middle from the force applied by the hammer, but that is exactly what it looks like. Maybe too soft of a pin to start with.
Belmont31R
12-23-09, 17:53
May have just been a bad part from the start. Primers are pretty soft, and wouldnt bend a steel firing pin under normal circumstances.
Thats why I keep a parts box (fishing tackle box actually)....
geminidglocker
12-23-09, 18:38
Nope, never had a single light strike or blown primer or anything with this rifle. The only thing I did to it was properly stake the carrier key. It's not like I stepped on it or anything like that. My small parts go right into a jar as I dissassemble my weapon. My Buddy from the shop has'nt shown up yet, I hope he does'nt leave me hanging til' tommorrow. I've found Ti pins online, so I suppose I'll order one of those and see how well that holds up. How often do you guys replace standard Stainless firing pins???
BufordTJustice
12-23-09, 19:10
Is your bolt carrier shrouded? That would be my first question.
geminidglocker
12-23-09, 19:22
The Bolt Carrier is a Semi-auto bolt carrier. I was able to chuck the pin in my vice and true it up with a brass hammer, took about fifty gentle taps. I know, just replace the pin, but I wanted to se if it could be trued. My friend has;nt shown up with my new one yet. Sounds like you know something I don't. The FA Carriers have the full shroud, right? Mine is the typical semi-shrouded type. I guess it's called "AR-15 Enhanced" according to the search I did.
G- Possibly just a lower quality part finally crapping out. So many variables with the steel that it's almost impossible to diagnose the issue. Would love to send it for testing just for our knowledge. Don't think the carrier is the issue. Good luck, stay safe, Merry Christmas!
geminidglocker
12-23-09, 20:38
G- Possibly just a lower quality part finally crapping out. So many variables with the steel that it's almost impossible to diagnose the issue. Would love to send it for testing just for our knowledge. Don't think the carrier is the issue. Good luck, stay safe, Merry Christmas!
I probably ruined the integrity of the part by bending it back, thus making testing a moot point, but if you PM me, I'll gladly sent it to you when I get my replacement. I'de just like to know why it failed. I'm gonna' give the Titanium replacement a try. I had Ti shafts on my Darts and they were terrifically resistant to bending. Infact, they never bent, but my Ex threw them out when I was gone when she left.
snip...The only thing I did to it was properly stake the carrier key...snip
You used the firing pin to stake it, didn't you?
It's OK, it's a punch looking thingee and handy when you're doing the job.
If you can, take a picture of the bottom of the carrier with the firing pin in place.
Lots of people here will be able to tell you right away if you have a shrouded pin.
Heavy Metal
12-23-09, 20:57
Outside of them bending due to the Firing Prin Retaining Pin breaking, I have never seen an AR Firing Pin go bad.
I have seen the tip deformed by a pierced primeer but it still worked.
geminidglocker
12-23-09, 23:18
Here you go.
http://i296.photobucket.com/albums/mm196/davecharlie08/bottomofbolt001.jpg
http://i296.photobucket.com/albums/mm196/davecharlie08/bottomofbolt003.jpg
http://i296.photobucket.com/albums/mm196/davecharlie08/bottomofbolt002.jpg
Thomas M-4
12-23-09, 23:25
Bolt carrier has a fully shrouded firing pin. For what ever its worth I would guess a defective firing pin.
Interesting problem would like to know for sure what actually was the cause.
geminidglocker
12-23-09, 23:35
Well, thanks for all the help guys, my friend never showed with the new pin, so I guess it's a good thing I trued it back up. I'll go out tomorrow and see if I can get it to happen again. If I break something I guess it's ok, as my new years resolution is to build or buy more rifles anyhow. I did a google search and got a link to a "Calguns" thread that was titled, "Why will an AR firing pin bend", but the link would'nt work.
Maybe I'm asleep right now and this is actually a dream. I say this because I have dreams where like my guns will break for no logical reasons.
Well, if I do damage the internals I'll just replace everthing with BCM parts. I'de like to try the Fail Zero products but I can really afford them right now.
I'd call Bushmaster. Perhaps they made more than just one firing pin with that blend of metal and it would be of interest to them to find the cause.
Anyways, order one off BCM and be happy again.
geminidglocker
12-24-09, 09:34
I'd call Bushmaster. Perhaps they made more than just one firing pin with that blend of metal and it would be of interest to them to find the cause.
Anyways, order one off BCM and be happy again.
I feel dumb now, I should have thought of that. Roger Wilco. Out.
I'll wait til' after Christmas. In theory any how, the FP should not have been able to bend at all, seeing as how the pin must be in pefectly lateral symmetry, in order to fit to and fro' inside the FP bore of the bolt. I know this because I had to fit the pin to the bolt. When it was bent it would not fully insert without force, which I was not about to try. I fitted the pin with care, then polished the worked area with 1600 grit sand paper, but only ever so gently, to correct any uneven surfaces. I maybe removed .0003. My calipers broke and I can afford new ones right now. Then it finally looked like new and dropped right in, and slide right out.
Perhaps it is an issue of Harmonics causing stress deformation over an extended period of time, and due to poor metalurgy. Anybody can make a firing pin, and though I am happy with this rifle, i am sure Bushy just gets their Firing Pins from the lowest bidder. I believe it is time to try an M-16 Bolt Carrier. I forgot to mention that this gun has an H buffer in it, might have changed the Harmonics.But that was installed last Winter. Well, thankfully their are so many things to learn about working on guns that the fun never ends.
Heavy Metal
12-24-09, 10:19
The only other possible explanation is there is a problem with the channel inside the bolt.
geminidglocker
12-24-09, 12:45
The only other possible explanation is there is a problem with the channel inside the bolt.
I inspected the Bolt quite thoroughly, but you can never be to sure so I'll tear it down right now and inspect again. When I worked in a Lab at Vermont Butter and Cheese Co. I always performed each test 3 times. It never hurts to go back and look for what you might have missed. Per that, the bolt itself would be the next logical place to look, since it covers the affected area of the pin. Thanks for the tip. I'll write more when I complete me bolt inspection. I will write more later. I'm not doing anything for Christmas, so at least now I have a good safe time to wring out any flaws in the system, and replace/upgrade parts as needed. Hoping for some post Christmas deals on AR stuff after the Christmas season.
Can you post some closer pictures of the firing pin? It definitely is fatigue failure but are there any blemishes on the surface of the pin? Is the pin the proper length?
geminidglocker
12-24-09, 13:53
Can you post some closer pictures of the firing pin? It definitely is fatigue failure but are there any blemishes on the surface of the pin? Is the pin the proper length?
I'll get around to it, I promise. My camera is not the best, 99.00 wal-mart kodak. I unfortunately cannot do any more gun work today, as an old friend stopped in, and since we each ain't got much family, I put the guns away, hidden, locked, etc: See, we intend to partake in Alcohol consumption tonight, so firearms will not be part of the equation. I'll get back to this thread in a couple of days, when my head does'nt hurt. Das Vedania.
Heavy Metal
12-24-09, 16:25
Make sure the shoulder on the Firing Pin bottoms out on the tail of the bolt.
Make sure they didn't short a drill bit somewhere.
geminidglocker
12-25-09, 04:04
As stated earlier, I fiitted the pin to the bolt. I'll post a video link evetually showing that the bolt spins like a Dradle on the Pin.
geminidglocker
12-25-09, 15:49
Update: I took it out today again, and still no problems.
The only other possible explanation is there is a problem with the channel inside the bolt.
I was thinking along the same lines as you. Ive never quite seen mechanical deformation in a pin like that. As another user mentioned it might be the material used as well.
my guess is that the firing pin was not bent in operation and that it was like this for some time before your found it. it's not that badly bent and would be somewhat easy to miss.
geminidglocker
12-29-09, 05:12
I ran 80 rounds of Wolf thru it today and it runs like a champ, I guess I fixed it.
The only time I have seen something similar, was when someone forgot to re-install the cotter pin that retains the firing pin, and the hammer bent it during opertaion and locked the gun up -- cracked the cam pin too.
geminidglocker
01-01-10, 12:47
Well, it's back in working order now, and I just ordered a Titanium replacement. I wanted a BCM bolt but they were out of stock.
geminidglocker
01-01-10, 16:46
So this Ti Firing Pin I ordered, anyone else running one? I paid 37.50 after shipping and handling.
So this Ti Firing Pin I ordered, anyone else running one? I paid 37.50 after shipping and handling.
If you hurry, there may be time to cancel the order.
Get a GI pin from a known-good vendor.
geminidglocker
01-01-10, 23:32
Yeah thanks. Your post was fantastically wonderful and beneficial. Any reason you say this?
Titanium is softer then steel. The only advantage it has is a faster lock time because it’s lighter.
Heavy Metal
01-02-10, 00:43
Well,
The T1 firing pins are a poorer material choice.
Steel takes repeated impacts better and Steel firing pins are far cheaper.
http://www.armalite.com/images/Tech%20Notes/Tech%20Note%202,%20Titanium%20Firing%20Pins%20ArmaLite%20considers%20Gener….pdf
Yeah thanks. Your post was fantastically wonderful and beneficial. Any reason you say this?
he likes to save $30???
:confused:
geminidglocker
01-02-10, 02:12
Point well taken. I'll order up a few steel ones aswell. Thanks for the insight. I never knew all these things about firing pins until now. Better I learn now than fail later.
It somehow got bent when it was out of the rifle. You fixed it. Forget about it.
It somehow got bent when it was out of the rifle. You fixed it. Forget about it.
I'd be concerned about work hardening from it bending and being bent back. I'd replace it, too.
It somehow got bent when it was out of the rifle. You fixed it. Forget about it.
A firing pin is a component that should be replaced, not repaired.
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