SOLVED Can someone please help me understand the mechanics of this

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Canuck65

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Background:

Tikka T3x Sporter in 223. Action trued and re-barreled by JC Customs to .222rem. Moved it into a B&C target stock. Beautiful job - everything's working great for years. About a year ago or so, I installed a Bix 'n Andy trigger (which s truly amazing). Set the sear engagement and trigger pull just the way I like.

Started to get the occasional failure to fire. Chalked it up to a bad batch of primers. However, the issue persists. Every once in a while I'll hear that click. Primer seating looks fine, dimple left by the firing pin looks okay - every other round went bang no problem.

Lapua brass, 2thou shoulder bump (so it's not a headspace problem), BR4 primers from 2 different bricks (haven't looked at lot numbers, but I assume they're different. After years and years of handloading, I'm pretty sure I know how to seat a primer properly. The spring is good, and the bolt/firing pin, etc are in perfect condition and clean as a whistle.

That brings me to the trigger. I have read that a trigger set too light can cause this issue. Mine is quite light (scary light), but it's safe, and there doesn't seem to be any sear drag as far as I can tell.

Assuming it is the trigger settings, can someone explain how a trigger pull set too low can cause light strikes? I wondered about sear engagement, but like I said, it's safe - I bumped it, shook it, banged it, etc and it won't accidentally fire - and I see no evidence of dragging (doesn't mean it's not happening though).

EDIT - I appreciate all your comments, but I'm asking about the trigger specifically here - THE SPRING IS FINE. Thanks in advance for your help.

SOLVED (I think). Firing pin travel is only .201 - sear position in the new trigger seems to be the culprit.
 
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For sure is not something that I have run into - is it possible that adjusting that trigger moves the sear forward? In other words, the firing pin fall is no longer the same?? I assume that with a coil spring there is some "build up" of the firing pin energy - with less travel, maybe it does not strike as hard?? But, like you, is not really apparent to me what swapping out to a different trigger has to do with whether the primer ignites or not. Do you have the option to re-install the old unit, to see if the phenomenon continues?

Really reaching, and I do not know the Tikka TX3, but is perhaps the bolt handle touching to that replacement stock? In a Mauser 98, if the bolt is not perfectly closed, the firing pin "wings" will bounce off the internal abutments within the bolt - and use up some energy of the firing pin fall, that would otherwise be delivered to the primer?
 
You say the spring is good but how do you know it is "good"? Try a new one...

You know how to seat primers... are they set flush? They should be slightly deeper than flush.
 
Canuck65 said:
Set the sear engagement and trigger pull just the way I like.
Click to expand...

Is there an overtravel adjustment, if so then it may need adjustment to increase overtravel. It may not be allowing the trigger to move far enough out of the way.
 
I don’t think that changing out the trigger has anything to do with the amount of force the firing pin hits the primer. Id say the spring is getting weak, or the firing pin is hanging up somewhere or is worn..just my two cents..
 
Potashminer. I’ll confirm to be sure, but I don’t think the seat moves forward. That being said, the whole mechanism may have some room to move backward.

Lodi. Thanks - this is good advice. I’ll look in to this. It’s something with that sear. Has to be.

Everyone else, thank you for the replies, it’s not the spring and it’s not the primer seating, but I appreciate you chiming in.
 
I remember reading somewhere about Bix 'n Andy triggers sometimes giving an internal "click" instead of dropping the striker. Is the firing pin actually being held back, and then dropping when the trigger is pulled?
If it is, my guess would be that the spring has taken set, or that the trigger adjustments have shifted and there is drag on the firing pin by the sear.
You can test the spring with a bathroom scale and a block of wood. 25 lbs is a pretty good rule of thumb for a minimum force required to reach full compression, if I remember the rule correctly.
 
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Jonnyofalltrades said:
I remember reading somewhere about Bix 'n Andy triggers sometimes giving an internal "click" instead of dropping the striker. Is the firing pin actually being held back, and then dropping when the trigger is pulled?
If it is, my guess would be that the spring has taken set, or that the trigger adjustments have shifted and there is drag on the firing pin by the sear.
You can test the spring with a bathroom scale and a block of wood. 25 lbs is a pretty good rule of thumb for a minimum force required to reach full compression, if I remember the rule correctly.
Click to expand...

I can see the cocking indicator moving - the firing pin is dropping. The spring is fine. I do suspect the sear, or something else about the trigger adjustment is to blame here though too.
 
Try the old trigger and if the problem is solved, return the offending trigger for a replacement. Let the manufacturer sort it out.
 
You say the indent on primer is good, do they fire on the second hit? Generally trigger weight has no effect on firing pin hit, it simply releases it to fall. The force of the strike is determined by the firing pin (striker) spring. The length of drop can be a factor, if the trigger is not holding the striker far enough back. Federal primers are generally the softest. I would try a few of those. The end of firing pin should be spherical and polished for best performance. Striker, spring and it's bore should be lightly oiled, no grease or heavy oils that can slow the fall especially in low temps.
 
Clean out the internals of the bolt and relube. Make sure the firing pin is not chipped or damaged. Confirm firing pin protrusion. use the factory trigger and see if problem persists.

If it does, change the firing pin spring... springs are a wear item and if you use the rifle alot, you will be changing the spring

Jerry
 
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