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-   -   Firing Pin Malfunction question (http://www.firearmstalk.com/forums/f33/firing-pin-malfunction-question-99729/)

Rocky7 10-31-2013 02:45 AM

Firing Pin Malfunction question
 
I have a Montana 99 action (sim. to pre64 Win 70) that is intermittently making a very poor firing pin strike with no ignition.

I have replaced the spring and put in a 30 lb. Wolff.

I have adjusted the firing pin extrusion to 0.85 with the bolt out of the rifle.

I have spun a cotton swab soaked in rubbing compound inside the bolt barrel.

I have polished the firing pin spring washers, thinking they might be binding inside the bolt barrel somehow.

It will fire a few or several rounds and then give me a dud. The first two loads this aft were duds and I didn't try any more. This was one of the duds and is typical of the problem. It is a too-shallow dent and the round did not fire:

http://i1210.photobucket.com/albums/...psa85fdf5f.jpg

Outside of an exorcism, can anybody think of anything I missed?

hiwall 10-31-2013 03:36 AM

Does it happen with factory loads?
Is the bolt handle completely down all the way when you fire?
Has the trigger been worked on?
If you reload then you can check it without going to the range by shooting primers only (caution they are very loud).
I am suspicious of the trigger/sear interfering with the striker movement.

Rocky7 10-31-2013 05:05 AM

Quote:

Originally Posted by hiwall (Post 1418463)
Does it happen with factory loads?
Is the bolt handle completely down all the way when you fire?
Has the trigger been worked on?
If you reload then you can check it without going to the range by shooting primers only (caution they are very loud).
I am suspicious of the trigger/sear interfering with the striker movement.

Sorry, don't know. I don't use factory loads. Might be worth a check, tho...

Yes.

No. It's a factory Rifle Basix trigger. I've used lots of them to good effect.

Yup. I did that at home and thought I had it fixed. The dang problem comes and goes.

Thanks for the suggestion. I am going to ponder that angle. I have some jeweller's eyepieces so will give those parts a long careful look tomorrow.

ps: Just finished taking the bolt apart (again) and polishing the firing pin and the sides of the cocking piece; none of which have any apparent roughness or gouges that might catch on something.

Thanks for the reminder on the primers; I'll give that a try out the back door in the morning.

robocop10mm 10-31-2013 06:25 AM

What about the ammo? Are you sure the primers are seated fully prior to firing (or attempting to fire)? A high primer can do this.

Mercator 10-31-2013 11:51 AM

hard primers 99%

Rocky7 10-31-2013 01:34 PM

Robocop, yes I've double checked that. I seat primers by hand and have been extra attentive to that possibility and am sure it is not the issue.

Mercator, I do use CCI primers - 250's in this rifle and am aware that CCI has a rep for hardish primers. The problem I have with that theory is that I have other rifles with M99 actions and they don't have this problem. Still, it's worth a look. I have some Win primers on hand and will try loading up some with those as well as the CCI loads and take all of that to the range... it would be odd that just this one action can't make a decent dent in a CCI primer but I should rule it out, I guess.

Thanks.

ps: Anybody have any suggestion for how a guy would polish inside the port/tunnel on the bolt face where the firing pin extrudes? It's too small to see any imperfection so I don't know if that's the issue but if I could get something small in there a bit of polishing might not hurt?

mountainman13 10-31-2013 01:48 PM

What does the head of the firing pin look like? Is there any chance it is peening?

Rocky7 11-02-2013 01:47 AM

It looks OK to me, mountainman13. The action has only fired maybe 200 rounds.

Had it out today. Fired two rounds and then FTF.

I'm off to my workshop for more polishing and study under a magnifying glass. Meantime, does anyone know if the firing pin spring can rotate inside a pre-64 Win 70 bolt? The M99 action has the same geometry and it has the same crescent-shaped retainer washer on the firing pin that holds back the spring. If the firing pin spring assembly is rotating inside the bolt, I'm wondering if that crescent washer might be clipping the bolt barrel ports?

Mercator 11-02-2013 02:02 AM

Quote:

Originally Posted by Rocky7 (Post 1420341)
It looks OK to me, mountainman13. The action has only fired maybe 200 rounds.

Had it out today. Fired two rounds and then FTF.

I'm off to my workshop for more polishing and study under a magnifying glass. Meantime, does anyone know if the firing pin spring can rotate inside a pre-64 Win 70 bolt? The M99 action has the same geometry and it has the same crescent-shaped retainer washer on the firing pin that holds back the spring. If the firing pin spring assembly is rotating inside the bolt, I'm wondering if that crescent washer might be clipping the bolt barrel ports?

Was it different ammo today?

I may be dragging behind this discussion, but a dry primer getting wet and drying again might become ornery. Any chance of that?

Rocky7 11-02-2013 04:01 AM

No, same handloads today, Mercator. Same primers. No, no chance these primers are contaminated. They are CCI250 and while this possessed rifle has been sputtering, I have loaded and fired those same primers in other M99 actions without a hitch.

Couldn't see anything wrong. Polished inside the bolt barrel (again), relieved (drilled) a wee bit off the rear end of the firing pin hole in case that was too far back and somehow snagging and then I swapped out the flat washer and the "C" retaining washer on the firing pin so will try that tomorrow if I can get before a snow storm that is due. I am resorting to the old auto mechanic approach - replace parts until it works.

(no offence to our auto mechanic members, but I've been on the receiving end of that procedure a time or two:))

I am wondering if I might have a cockeyed hole drilled in the end of the bolt; i.e., not truly square and sometimes the firing pin tip binds in there.

Anyway, I've ordered an aftermarket firing pin and spring so will try that when it arrives. Might take the bolt barrel to a machinist, too, and see if he can tell me if it's true.

If all of that fails, I may get out my BFH.:)


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