Firing pin spring weight?

G

Gene Beggs

Active member
There has been a lot of discussion about the importance of good ignition in rimfire rifles but I don't recall anyone saying anything about how to determine when a spring needs to be replaced. Is there a specific minimum weight when the spring is relaxed? Fully compressed? Is there a special tool/fixture/ scale or whatever for accurately measuring spring tension or is it just a feel/judgement call?
 
Gene, I don't think anything like that exists. Most,either go with a reasonable time frame, say every 2-3 years, or any time the baseline performance seems to change......less than scientific.
 
Gene
I would look more at the cocking piece hitting the trigger side plates than a weak spring. A gunsmith has to tell a customer what they want to hear at times.
 
A scale and a means of measuring the spring at it's compressed and/or it's installed height, can be used to check springs. I've also fashioned them from fish scales.
 
Gene Beggs said:
There has been a lot of discussion about the importance of good ignition in rimfire rifles but I don't recall anyone saying anything about how to determine when a spring needs to be replaced. Is there a specific minimum weight when the spring is relaxed? Fully compressed? Is there a special tool/fixture/ scale or whatever for accurately measuring spring tension or is it just a feel/judgement call?
Click to expand...

Gene,
I just happened onto this discussion: http://www.rimfireaccuracy.com/Forums/archive/index.php/t-1056.html?

The consensus seems to be that that a 0.0013 - 0.015" rim indent is about right. This is a measurement of the effect, rather than the input. Kinda makes sense to me.

Cheers,
Keith
 
Gene

Gene Beggs said:
There has been a lot of discussion about the importance of good ignition in rimfire rifles but I don't recall anyone saying anything about how to determine when a spring needs to be replaced. Is there a specific minimum weight when the spring is relaxed? Fully compressed? Is there a special tool/fixture/ scale or whatever for accurately measuring spring tension or is it just a feel/judgement call?
Click to expand...

The way I realized my spring needed to be replaced on my Suhl was the performance fell off dramaticly especially on the 13.5 target, it seemed to be OK on the 10.5 but just was all over the place on the 13.5 target, after replacing the spring it was like a new gun. I was probably getting some erratic shots but didn't connect it to the spring until it just went to heck at the crawfish this past year.It would be nice to have some type of test measure to check but I don't know of one myself.
MC
 
Mike
Are you sure it was the spring or the focus ring on your tuner. Did you turn that first to get your groups round again? Just asking. No hooch or agression here.
 
GordonE said:
Mike
Are you sure it was the spring or the focus ring on your tuner. Did you turn that first to get your groups round again? Just asking. No hooch or agression here.
Click to expand...

Nope it was the spring, shot a 250-23x in 10.5 yards then a 248-14 13.5 and thought it was strange how it fell off on the 13.5, then in meters shot a 250-17 10.5 followed by a 243-11 and knew there was something wrong, checked my cases and saw there was barely a mark on them and decided to change the spring, after changing, it was like a new rifle.
MC
 
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Thanks Keith

mks said:
Gene,
I just happened onto this discussion: http://www.rimfireaccuracy.com/Forums/archive/index.php/t-1056.html?

The consensus seems to be that that a 0.0013 - 0.015" rim indent is about right. This is a measurement of the effect, rather than the input. Kinda makes sense to me.

Cheers,
Keith
Click to expand...



Very good info Keith. Thanks for passing that along. Revealed some things I had not thought of. The more I learn about rimfire BR the more I appreciate those who have reached the top of the sport as shooters and gunsmiths.

Later,

Gene
 
Consistency

There has been quite a bit of discussion on the different forums about lite vs. heavy springs & pins. It seems that heavy is preferred.
Isn't it really most important to have a consistent indentation on the case regardless of spring weight? Time & time again?
That said is the heavier preferred as it is less effected by oils, debris, etc. giving the more consistent ignition? Or is it some other reason?
Thanks
Keith
 
Heavier is generally more consistant for a variety of reasons, not the least of which is overcoming occaisionally mechanical interference such as Gordon described.
 
Bang

Gene,
A Rim Fire either goes BANG! or it does not!!
The weight of the Spring does not effect the Bang!
(or accuracy etc)
Make Sense?
 
QUOTE=Doug
Gene,
A Rim Fire either goes BANG! or it does not!!
The weight of the Spring does not effect the Bang!
(or accuracy etc)


It certainly does Doug, I figured you knew better than that.\
MC
 
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Lapua Gold Box

When Lapua had their supurb Gold Box Ammo Eitiher based priming. When they had to switch to water based. About twelve years ago. Ignition with Either Could and i mean COULD be a hell of a lot easier to get. Small imprint could result in not crushing enough to get consistant ignition.
 
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