Firing pin Problems?

S

shootingisfun

Guest
Good evening folks,

I have a problem that is giving me grey hair. I'm having problems with inconsitent ignition in a rifle I built. When the round doesn't go off, it appears that the primer was not struck hard enough (small dent in primer). Tried handloads and factory ammo with the same results.The rifle is based on a Remington 700 with a PTG custom bolt.

Firing pin protrusion measures .057 to .059. I thought it may be a weak main spring, so I changed it out to a brand new one. I still have the same problem. I checked the headspace and it falls within SAAMI specs.

Any input on this subject from the masters here would be greatly appreciated!
 
I'm not one of the masters

but, when checking the headspace with a go & no go how much headspace over the go do you have??

The only rifle I've seen this happen on was a 6BR that had +.003" over a go gauge for headspace. The rifle would experience a fail to fire every so often when firing new brass. Once fired, sized brass was used the problem went away. The shoulder on the fired brass was being bumped .0015"-.002" I have a PTG bolt body in a new build I have, works flawlessly.
 
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safety lever

You might want to check the sear safety cam hitting the cocking piece on the bolt with the safety off. I had a remington 700 in my shop a few months ago with the same problem. The safety lever pivot pin hole was drilled to low causing the safety to ride to high in the trigger therefore causing the cocking piece to drag on the sear safety cam when fired. Hope this helps.
 
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When the bolt is in the fired position in the rifle, is there a slight amount of play lifting the bolt handle... or does the bolt handle have no movement?

It should have a little movement indicating the firing pin is fully forward with no friction.
 
I'm +.003" over the go gauge. I've tried brand new brass, once fired full length sized and once fired neck sized brass. None of these fixed the problem.

I'm using a Jewell trigger. It's been used in other rifles with zero problems.

The bolt does have a small amount of play once the trigger has been pulled.

As for a frag of primer being the problem, it's unlikely. The bolt face has been cleaned numerous times and I haven't seen any frags on it.
 
Shootin' - -

after checking all the above sugestions if not resolved,
check your unfired case length versus your "GO" gauge
length. There may be a problem there that just seating
a bullet long will NOT cure. A secondary shoulder/doughnut might keep the case head against the
biot face.
Steve Moore
 
Have you measured the spring weight?

Is the cocking piece retaining pin protruding and dragging inside the shroud?
 
Dennis Sorensen said:
Have you measured the spring weight?

Is the cocking piece retaining pin protruding and dragging inside the shroud?
Click to expand...


Could you elaborate on measuring the spring weight? I checked and it doesn't appear that the retaining pin is dragging inside the shroud. It appears to be centered through the cocking piece.
 
Another thing to check is the firing pin travel.

With the bolt out of the rifle, measure how far out the back of the shroud the cocking piece is, then rotate the cocking piece to the fired position and measure how far below the back of the shroud the cocking piece is. Yopu can also set up a dial indicator to measure this. Then put the bolt in the reciever and repeat to make sure you get the same measurement as with the bolt out.

Even though the trigger has been in other actions, you may want to try a factory trigger to see if it makes a difference. I recently had a very popular aftermarket 2 oz. trigger where the sideplates extended to far above the trigger mounting pin holes. It bound the trigger sear bar up slightly and caused me all sorts of problems.
 
shootingisfun said:
Could you elaborate on measuring the spring weight? I checked and it doesn't appear that the retaining pin is dragging inside the shroud. It appears to be centered through the cocking piece.
Click to expand...

If you take the firing pin assembly and holding the shroud, push the tip of the pin down on a scale until the spring is fully compressed.. then read the scale as you slowly release the pressure... as soon as the cocking piece begins to lift, the scale reading is the weight of the spring. Remington springs are usually about 24 to 26 pounds...
 
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Al Nyhus said:
Another thing to check is the firing pin travel.

With the bolt out of the rifle, measure how far out the back of the shroud the cocking piece is, then rotate the cocking piece to the fired position and measure how far below the back of the shroud the cocking piece is. Yopu can also set up a dial indicator to measure this. Then put the bolt in the reciever and repeat to make sure you get the same measurement as with the bolt out.

Even though the trigger has been in other actions, you may want to try a factory trigger to see if it makes a difference. I recently had a very popular aftermarket 2 oz. trigger where the sideplates extended to far above the trigger mounting pin holes. It bound the trigger sear bar up slightly and caused me all sorts of problems.
Click to expand...


I've measured the firing pin protrusion from the front of the action, with the barrel removed. I used a depth mic and that's where I got the amount of protrusion from.

The trigger was used on this very same action (before I rebuilt the rifle) without any problems. I've also used a factory trigger both before and after, thinking the Jewell may have been the problem.
 
Dennis Sorensen said:
If you take the firing pin assembly and holding the shroud, push the tip of the pin down on a scale until the spring is fully compressed.. then read the scale as you slowly release the pressure... as soon as the cocking piece begins to lift, the scale reading is the weight of the spring. Remington springs are usually about 24 to 26 pounds...
Click to expand...

Thanks a bunch.......I'll give that a try tomorrow.
 
shootingisfun said:
I've measured the firing pin protrusion from the front of the action, with the barrel removed. I used a depth mic and that's where I got the amount of protrusion from.
Click to expand...

I saw that you had measured the firing pin protrusion. My suggestion was to measure the amount of firing pin travel. :) -Al
 
Is your bolt timed properly? Check to see if the cocking piece is hitting the bolt body somewhere other than the bottom of the cocking cam. This happens when the bolt is under or over rotated.
 
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The firing pin striker should not bottom out/touch in the cocking cam radius of the bolt body.
The firing pin stop/gas check,by design, is the shoulder of the firing pin.
 
It is time to do a some old style trial and error investigation..take the barreled action out of the stock...holding the assemble by the barrel in a padded vise...with the action trigger UP...dry fire the action (NO AMMO) and listen to it if you hear the firing pin strike (sound) vary greatly..do not open the bolt..but look at the cocking piece and see if it fell short...look at the bolt shroud to see if it is canted to one side at an odd angle...
Also did you put the original factory firing pin assembly into the PTG bolt.?
It is possible the bolt shroud is threaded in too far and when you close the bolt the bolt shroud is binding against the cocking piece..it should have some rotational play..if not it could be binding on the cocking piece...
 
eww1350 said:
It is time to do a some old style trial and error investigation..take the barreled action out of the stock...holding the assemble by the barrel in a padded vise...with the action trigger UP...dry fire the action (NO AMMO) and listen to it if you hear the firing pin strike (sound) vary greatly..do not open the bolt..but look at the cocking piece and see if it fell short...look at the bolt shroud to see if it is canted to one side at an odd angle...
Also did you put the original factory firing pin assembly into the PTG bolt.?
It is possible the bolt shroud is threaded in too far and when you close the bolt the bolt shroud is binding against the cocking piece..it should have some rotational play..if not it could be binding on the cocking piece...
Click to expand...

Thanks, I'll do that today. I did put the original factory firing pin assembly into the PTG bolt.

Thanks to everyone for their input. I should be able to get back on here later tonight and I'll let you know what I come up with.
 
If the spring is weak, you will get punched primers, the firing pin hits the primer, the spring prevents the pressure from pushing the firing pin back, it is a PSI X area thing.

The firing pin will not rotate because of design, strip the bolt and firing pin assembly, insert the firing pin only into the bolt, then measure firing pin protrusion, by design once the bolt and firing pin is assembled, the protrusion does not change, once a firing pin is inserted into the bolt, the firing pin will not rotate because of an internal slot in the head of the bolt, if there is dirt, grit or grime in the slot, travel will be compromised.

Controlled feed and head space? Hatcher chambered 03s with .100 head space without light strikes or failure to fire, I have 8X57 cases that were fired in an 8/06, that is equal to .129 head space, no light strikes, no head space issues etc., just short necked 8/06 cases. To say the cartridge can move forward fast enough to avoid a strike is to say there is enough room between the extractor and receiver ring to move over far enough to allow the rim of the case to jump the extractor, every time I jump the rim with the extractor it cuts the rim, neither the firing pin and extractor rotate.

F. Guffey
 
forgive, the forward travel of the firing pin is controlled by the bottom of the cocking (cam slot) slot at the rear of the bolt.

F. Guffey
 
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