Misfires and bolt actions
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#1: Misfires and bolt actions Author: roklokLocation: Fairbanks, Alaska PostPosted: Fri Feb 03, 2006 8:18 pm
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I just had to respond to a comment made in the misfire and deactivating primers string,but was locked out for whatever reason.It was stated that a bolt action is either cocked or uncocked and short stroking it will not cause a weak primer strike. It is true that they are either cocked or uncocked,however not closing the bolt completely will DEFINITELY cause a weak strike on primer,at least on modern cock on opening bolt guns like the model 700,77,or 70 to name a few. If the bolt handle is not lowered completely, upon firing the cocking piece will slam into the camming cut on the bolt body instead of traveling forward unimpeded. The striker will have to finish closing the bolt before the firing pin ever touches the primer taking away much of its force.

#2: Re: Misfires and bolt actions Author: sniperLocation: Utah PostPosted: Fri Feb 03, 2006 9:47 pm
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roklok wrote:
...however not closing the bolt completely will DEFINITELY cause a weak strike on primer,at least on modern cock on opening bolt guns like the model 700,77,or 70 to name a few. If the bolt handle is not lowered completely, upon firing the cocking piece will slam into the camming cut on the bolt body instead of traveling forward unimpeded. The striker will have to finish closing the bolt before the firing pin ever touches the primer taking away much of its force.


roklok:

I had never thought about that before, but you are right. Aren't we talking about two separate things that are part of the same action, though? "Short stroking" is cycling the bolt too little to pick up a new round and chamber it, but isn't not fully closing the bolt called being "not fully in battery"?

It is very likely that NFIB occurred during the stressful situation you found yourself in, resulting in the conditions you described, and not ammo or any flaw in the gun... except for the second try you gave the round. That is puzzling.

Then the question raised its head: In the older, cock on closing actions, and I'm not sure which those were, was the camming surface set up opposite of what modern actions are? If so, with a failure to completely close the bolt, it seems that the striker assembly hitting the camming surface would knock the bolt open, and if the round fired, the bolt, brass, and gas would be blown out of the action, back into the shooter's face.

It has been 50+ years, but I faintly remember ads for kits to convert the old bolt actions to cock on opening, and new guns advertising the fact that they had the feature. I can remember thinking "I want that. " Maybe this is a safety feature that was/is not widely known? The gun makers quietly fixing a rare, but serious problem?

What do you guys think?

#3: Re: Misfires and bolt actions Author: Dimitri PostPosted: Sat Feb 04, 2006 9:15 am
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The M1917 Springfeilds were cock on close I belive. So are the Lee-Enfeilds. Smile

I've handled a Enfeild at a hunting show once, I can tell you think with its cock on close if you dont close it all the way the only thing that will happen is the bolt will move back and it wont let you hit the primer to shoot it Smile

"Out of battery" problems such as explosions cant happen with them the spring that makes the firing pin stay in the uncocked position will push the bolt back and not allow the trigger to engage it unless its completly closed.

Dimitri

#4: Re: Misfires and bolt actions Author: roklokLocation: Fairbanks, Alaska PostPosted: Sat Feb 04, 2006 3:05 pm
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I was never fully positive what all "short stroking" encompassed.I know most often it is a term used to describe not withdrawing the bolt fully rearward as you said. As far as cock on closing rifles,they dont have a camming cut on the bolt, they use a sear that catches the cocking piece as the bolt is closed. Usually about 1 inch before the bolt is fully forward and able to be turned down you can feel extra resistance as the firing pin spring is being compressed.The Savage 99 lever action also uses this system. At any rate I believe that not getting the bolt fully closed or in battery was probably what caused my misfire.Bear fever!!



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