firing pin not centred.
- Thread starter ileso
- Start date
I've seen it a lot, slightly off-center is fine, nearer to the edge than the middle would suggest a worn hole/pin in the boltface and 'could' potentially be a problem.
I presume you aren't getting miss-fires ?
Ignoring the over pressure signs, these were fired in two different rifles ... slightly different pin diameter and position.
I presume you aren't getting miss-fires ?
Ignoring the over pressure signs, these were fired in two different rifles ... slightly different pin diameter and position.
does it go bang?
reloader54
Well-Known Member
ooh look, heads. 
Ronin
Distinguished Member
The pin being off centre will not affect the firing cycle
In a sporting rifle it would have little bearing on “minute of deer accuracy” unless as previously stated the strike is on the edge of the primer which would be dangerous as pierced primers may result
From an extreme accuracy perspective, an eccentric firing pin may cause inaccuracy
I say this because the non central (eccentric firing pin) may drag or strike the bolt tube and lose force / jam and be inconsistent with firing pin strike on the primer
The bolt may also be eccentric to the bore line causing uneven forces to have a negative effect on the action during the firing cycle
It’s been well documents by H Vaughn in his book Rifle Accuracy the Facts about the negative effect on accuracy the bolt lugs being misaligned with the bore and the subsequent forces causing the barrel in the tenon to move unevenly during the firing cycle under these situations causing the odd flyer or unexplained fall of shot
The above wouldn’t be something to worry about in normal sporting applications - I’m using the above as an extreme example as building accurate rifles is my goal whenever I take on a commision
Miki’s inages shows two set of cartridges fires with large and small diameter firing pins - no issues really with either, though evidence of over pressure with ejector wipe marks,,,,,,
Hope that helps
In a sporting rifle it would have little bearing on “minute of deer accuracy” unless as previously stated the strike is on the edge of the primer which would be dangerous as pierced primers may result
From an extreme accuracy perspective, an eccentric firing pin may cause inaccuracy
I say this because the non central (eccentric firing pin) may drag or strike the bolt tube and lose force / jam and be inconsistent with firing pin strike on the primer
The bolt may also be eccentric to the bore line causing uneven forces to have a negative effect on the action during the firing cycle
It’s been well documents by H Vaughn in his book Rifle Accuracy the Facts about the negative effect on accuracy the bolt lugs being misaligned with the bore and the subsequent forces causing the barrel in the tenon to move unevenly during the firing cycle under these situations causing the odd flyer or unexplained fall of shot
The above wouldn’t be something to worry about in normal sporting applications - I’m using the above as an extreme example as building accurate rifles is my goal whenever I take on a commision
Miki’s inages shows two set of cartridges fires with large and small diameter firing pins - no issues really with either, though evidence of over pressure with ejector wipe marks,,,,,,
Hope that helps
enfieldspares
Well-Known Member
Well I never knew that. Nor did Herb Woodend. Not true. Whoever told you that is talking rot. That it may appear to be off centre is correct. It does so because of chamber tolerances rather than by design. And the cartridge laying in the "bottom" of the chamber as it were. I can assure you that Enfield firing pins are straight and that Enfield bolt heads have the hole through which the firing pin passes drilled central.
Sinistral
Well-Known Member
I was assuming the OP was talking about the firing pin indent being slightly off-centre rather than wildly off. Nevertheless, most people do spot this and mutter to themselves.
For a start, not all case heads have the primer pocket perfectly central so the extent of this varies a bit by brand. Also I’ve noticed that the strike in each of my Tikka’s in .22-250, .243, and .270 are off-centre but the 6.5x55 which has a larger rim is dead on. The bolt-faces measure the same on the caliper, which is curious.
ileso
Well-Known Member
absolutely, .. one does mutter.I was assuming the OP was talking about the firing pin indent being slightly off-centre rather than wildly off. Nevertheless, most people do spot this and mutter to themselves.
well thanks guys for your replies. I had always wondered how, if the bolt is square with the rest (I assume) and the pin fits snug in the hole it would even be possible. It always did this since I bought it.
Heads with pressure signs for sure.ooh look, heads.
My .22h hits the primers off centre no issues at all
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