firing pin too long

[wakerider]

Is there anybody that trouble with their firing pin being too long. That seems to be my discovery, went through 6 firing pins. I started out blowing primers so I dropped the charge down below recommended minnimum on several powders and still punched primers. Then I filed the pin down and tried again and solved the problem. Is this because the bolt is milled down too much? If anybody can answer I'd appreciate it.

Rick

[stokesrj]

Hi Rick,
I've never heard of a firing pin being to long, that would indeed be a rare occasion. However, I've seen several firing pins that would pierce the primers due to a flame cut on the tip. These can be very difficult to see but you can feel them. I would think it would be more likely that you had a flame cut and by shortening the firing pin you removed the offending cut. Of course you can't go back in time and know for sure, but you could replace it with a new firing pin and see if in deed it was the length or the condition of the tip that was root cause.
Also what primers were you using? Many small rifle primers are not suitable for an AR and should be avoided. Among these are Winchester Small Rifle, Remington 6.5 and CCI 400. This is because the wall thickness is to thin and increases the chances of a slam fire to an unacceptable level and will lead to premature piercing as well. Thick walled primers are to be used in the Grendel such as Remington 7.5, CCI 450, 41 and BR4, and my favorite, Wolf Small Rifle Magnum (Tula, PMC and so on are the same).
Bob

[kamrr4437]

you might want to check your headspacing. Sounds like a possible headspacing issue. I dont think the firing pin would be to long. Sounds like the round is to far back so i would say some type of headspacing or possibly the wrong bolt maybe?

Keith

[fanofflyn]

The Winchesters not to use are the new blue box ones with the yellow metal. The old white box WSR with the silver metal are harder. Of course, I'll have to rework my loads when I run out of the next several thousand of those.

[Whelenon]

Have the firing pin protrusion measured. Call a gunsmith and ask if they have a firing pin protrusion gauge. It would only take a couple of minutes to check it.

A long firing pin is rare, very odd. I would check all mating parts, are they correct? Make sure that there isn't some other problem going on.

[LRRPF52]

When you say you went through 6 firing pins, does that mean they all were too long? If so, it is your bolt. The tail end of the bolt might be too short. What is the source of your bolt? What is your bolt's face depth?

If it is .125", it is a 7.62x39 bolt.

If it is .135", it is a Grendel bolt.

Neither should matter though, since they are both made to space the standard AR15 firing pin correctly.

[Variable]

Maximum "Go" for firing pin protrusion should be .036", and any less than .028" is a no-go.

You can buy a gauge if necessary here: http://www.bushmaster.com/products.asp?cat=15

I've never actually encountered an out of spec pin for length (having gauged very many in the service), but I do have one bolt in a drawer somewhere that prevented proper pin protrusion due to an improperly machined firing pin channel. That bolt came in a "bargain" parts kit from Model 1 back in the 90's.

[RangerRick]

Didn't they make some long firing pins for people shooting 7.62x39 in the AR? Seems I remember that people were having misfires with the cheap ammo and standard pins.

This is from Arf com:

Q: Can I shoot surplus 7.62x39 in these rifles?
A: Depends. Some people have issues with 'surplus' due to the hard primers. The AR-15 firing pin isn't quite long enough. The usual fixes are either a stronger hammer spring, or taking 0.005"-0.007" off the tail end of the bolt to allow the firing pin to reach the right protrusion length for 7.62x39; or by putting the firing pin in a drill and use a file to take that much off the face of the flange. MGI produces a bolt and firing pin combo optimized for eastern European steel case ammo.

Did you get some of these?

RR

[wakerider]

Hello gentlemen I checked the bolt face dept and it is .1495, the bolt came with the barrel and it's a Satern barrel I ordered from Midway. I guess I should order the go no guage, but everything seems tight and the gun locks up properly. I'm averaging 1/4 to 1/2 groups at 100 yards at my best, but pretty regularly. What should I do order another bolt?
again thankyou Rick

[wakerider]

I've just read a thread from Medicman and in it Satern said they sent out a bad batch of bolts with their barrels awhile back to Midway I guess I should get a hold of Satern and find out what's going on.

Rick

[leopard6.5]

Rick: Definitely contact Satern as Deb(Satern) had posted on the forum before that there was a batch of barrels out of Midway USA that were sent out by Midway USA with the wrong bolt.

They have been replacing the bolts as they find out who has them.

Good luck.

Lee