firing pin force

[arpythehun]

Looking for an answer regarding firing pin force. I dry fired a 308 and I watched the scope picture jump about an inch at 100ish yds. I repeated the dry fire and it happened again, so, it's not my trigger control. I suspect that the cause is the firing pin hitting the bolt at the end of it's travel. I remember reading something about this not being good. I tried to find info on this subject in the Rifleman's Journal and didn't find any so far. I know that the primer will absorb most of the force, but what if there is an excess of force and the firing pin still is stopped by the bolt. Is this possibly a problem for accuracy? I replaced the old one which didn't look good with one from Brownell's which was a step up from the minimum strength spring for that rifle in their catalog. The gun is a 1903A3 stamped Remington has "mark II" on the firing pin knob. I bought it 20 yrs ago after it had been converted to a sporter, a benchrest barrel and a Dayton Traister trigger put on it. Shoots ok but I'd like to see it do better. I bought another bench rest barrel for it. Any thoughts

 

[Dans40X]

Other than installing a lighter main spring or molesting mil spec parts on your '03 A3.

Congrats on owning the finest controlled round feed action ever made.

Lock time will always be ....just slightly faster than a flint lock.

Follow thru is the key!

 

[BoydAllen]

Just an inch? Seriously, if you look at the weight of your firing pin assembly, how far it falls (heavy hammer, big swing), and compare it to modern actions, you will have the reason for the jump. Fortunately, primers do a pretty good job of cushioning the blow, so what you actually get when firing a live round is a lot better than what you are seeing on an empty chamber. Beyond that, enjoy your classic for what it is. Trying to make it into something that it is not would be a waste of time, and besides it will do everything that it was designed to, and more, just as it is.

 

[Robert]

Looking for an answer regarding firing pin force. I dry fired a 308 and I watched the scope picture jump about an inch at 100ish yds. I repeated the dry fire and it happened again, so, it's not my trigger control. I suspect that the cause is the firing pin hitting the bolt at the end of it's travel. I remember reading something about this not being good. I tried to find info on this subject in the Rifleman's Journal and didn't find any so far. I know that the primer will absorb most of the force, but what if there is an excess of force and the firing pin still is stopped by the bolt. Is this possibly a problem for accuracy? I replaced the old one which didn't look good with one from Brownell's which was a step up from the minimum strength spring for that rifle in their catalog. The gun is a 1903A3 stamped Remington has "mark II" on the firing pin knob. I bought it 20 yrs ago after it had been converted to a sporter, a benchrest barrel and a Dayton Traister trigger put on it. Shoots ok but I'd like to see it do better. I bought another bench rest barrel for it. Any thoughts

A 1903 has an heacvy FP, a strong spring and 1/2 inch FP travel (more than twice the Rem700). There is little you can do against that.

R.G.C

 

[Gundoktr]

Sounds to me like it might be the bolt handle. Either going down too far or not far enough causing the cocking piece to contact the sides of the cocking slot in the bolt. Does the bolt handle jump when you dry fire it?

Jim

 

[fguffey]

arpythehun. I try to avoid this type of question on this forum, Reminds me of The Miami Dolphins and their lineman named Incognito, too many people believe they are correct because the are rude and loud, in the real world I never had to tolerate big, loud and rude.

I will make an attempt to say something like 'THINK ABOUT IT'. the firing pin falls before the bullet leaves the barrel, I am told by the rude, big and loud the case, powder and bullet hit the front of the chamber before the primer is crushed. So if timer is a factor and the firing pin drives everything forward before the powder has a chance to build pressure a lot of time has passed.

Back to 'Think about it' I was setting at a red light, the light changed, I looked both ways, nothing, then? I went sailing through the intersection at 40 mph. My front bumper was not damaged, the rear bumper was destroyed. My rear bumper was destroyed before the rest of the auto absorbed damage or before the rest of the vehicle started to move. Back to the firing pin strikes the primer and the whole shooting match takes off to the front of the chamber before the primer is crushed.

I have killer firing pins, my firing pins crush the primer before the case, bullet and powder know their little buddy the primer has been crushed. All of this happens in milliseconds, then there is the .7854 factor. There is lock time, there is the effect the finger has on the trigger.

And always forgotten, the dent in the primer, the firing pin is driven back by pressure inside the primer. The primer conforms to the shape of the firing pin.

Time is a factor.

F. Guffey

 

[BoydAllen]

Vibrations have a dwell time. They ring, especially if the material is metal. For that reason it is not so much about when they start, as when they finish. I know a top benchrest shooter in the NW region that is able to feed his single shot return to battery rig (rail gun) so quiclky that the vibration from one shot influences the one following it, so he has wrapped the barrel in material that damps the vibration. At that level, it makes a difference that he can see. Yes I know that a sporterized Springfield is about as far from that example as one can get, but my point was about dwell time of barrel vibration. For accuracy work, it is no accident that none of the popular actions have long pin falls or pins that are as heavy as the Springfield's. As to their spring weight, the Wolff Gunsprings site tells me that the stock weight is 16#.

 

[arpythehun]

Other than installing a lighter main spring or molesting mil spec parts on your '03 A3.

Congrats on owning the finest controlled round feed action ever made.

Lock time will always be ....just slightly faster than a flint lock.

Follow thru is the key!

It is one fine rifle and the lock time suck so I do focus on trigger control and follow through, thank you

Sounds to me like it might be the bolt handle. Either going down too far or not far enough causing the cocking piece to contact the sides of the cocking slot in the bolt. Does the bolt handle jump when you dry fire it?

Jim

it is not the the bolt handle, it all works properly


It looks futile to attempt to eliminate the problem short of building a custom firing pin. It will make a fine hunting rifle.

 

[fguffey]

http://riflemansjournal.blogspot.com/2009/08/history-dad-farr-and-farr-trophy.html

A man shows up without a rifle, they issue him a rifle from a rack, he determines there is something wrong with the accuracy.
He then finds it necessary to pick another rifle from another rack. What was the difference between the two rifles? The same shooter shot both rifles. Problems perceived here did not effect Mr. Farr.

An ace in WW11 was asked why there was a difference in pilots skills, they were flying the same plane and took the same training, he answered "eyesight", he claimed he could see the enemy long before they could see him and when he said "There they are" no one flying with him argued, they ask: "Where?".

Then there are primers for every occasion, reloaders take the manufacturers word for the amount of effort required by the firing pin to fire.

F. Guffey

 

[Raythemanroe]

Isn't the idea of the Tubbs Ignition system to speed up lock time? I don't think it is to so much reduce vibration or lesson the bump because he uses a stiffer spring..My Ruger was slow and you could see it in the scope..I couldn't find any Lite weight pins being sold anymore so I bought the chrome silicon spring and had the pin fluted..I haven't gained any ignition problems and cut the lock time by half it seems..


Ray

 

[BoydAllen]

Light weight pins are available for a wide variety of actions, from Gre-Tan Rifles and Pacific
Tool and Gauge. I think that it is momentum that jars our cross hairs, and KE that sets off the primer. They are different calculations. The only problem with a heavier spring and lighter pin, for benchrest, is bolt lift. I have tested it on my Viper and one of Greg Tannel's light pins and the heavier spring that is paired with it (25# vs. 19#) produce less disturbance of of the reticle, when dry firing, than the stock steel pin and 19# spring that came in the action. The light pin and heavier spring cut momentum way back, and give about the same KE.

 

[Raythemanroe]

Light weight pins are available for a wide variety of actions, from Gre-Tan Rifles and Pacific
Tool and Gauge. I think that it is momentum that jars our cross hairs, and KE that sets off the primer. They are different calculations. The only problem with a heavier spring and lighter pin, for benchrest, is bolt lift. I have tested it on my Viper and one of Greg Tannel's light pins and the heavier spring that is paired with it (25# vs. 19#) produce less disturbance of of the reticle, when dry firing, than the stock steel pin and 19# spring that came in the action. The light pin and heavier spring cut momentum way back, and give about the same KE.

I would agree with Boyd, but maybe in hunting and lighter rifle used off hand a lot faster lock times would be desired..

Ray