accuracy vs hammer strike

[tew45]

I have a small action FBW rifle I built several years ago in .219 Zipper. The hammer fall is enough to fire reliably but seems to be too light. I wonder if a light hammer fall affects accuracy by not having a strong ignition. Any thoughts on this would be interesting!

[GBertolet]

Yes it can. I am not sure where the cutoff point of lightness is, but past that point, it can. Even though the gun goes bang, the ignition of the powder charge, can be erratic, affecting accuracy.

[M-Tecs]

Yes. Light strikes do effect accuracy in target rifles. Lots of info and theories on the web I have experienced light strike accuracy related issues a couple of times.

[marlinman93]

Hammer strike is probably even more important or at least equally important as firing pin length! Either can cause issues. But hammer strike usually is never an issue if it's a bit heavy, like it is if it's a bit light.
Firing pin length can cause issues if it's less than .040" or more than about .055" long. Either way can create ignition issues.

[Tatume]

Precision Shooting (now out of print) published a study on this. They concluded that light strikes contribute to erratic primer flame (as others have noted). They went further to test what level of primer strike was sufficient. In the end they said that if a wooden pencil that has never been sharpened was dropped down the barrel un-sharpened-end first, and the barrel held vertically while the trigger was pulled, the pencil should be driven to the muzzle (not necessarily out of the barrel, but visible to an observer before it dropped back out of sight). This is not a very high-precision test, but a simple go/no-go. Of course, for smaller bores a substitute for the pencil must be found.

[Win94ae]

the pencil should be driven to the muzzle (not necessarily out of the barrel, but visible to an observer before it dropped back out of sight).

That is how I usually test a gun to see if it fires, most of the pencils shoot up about a yard.
I live dangerously, I use sharpened pencils!

If I add a drop of oil on my firing pin, my 30-30 would have primer strikes light enough to not fire the round. I just tried it with and without oil, both times the 6 inch wooden dowel shot up about 1 yard. The 30-30 shoots 1MOA regularly.