Bolt handle touching stock? Info re Accuracy and kinetic energy

[Bryan Blake]

 

[Richard Jones]

What a great visualization for a common issue. Thanks.

 

[Alexander-M]

Thank you for sharing, Bryan! Very well done. What brand tablet oscilloscope were you using?

Thanks!
Alex

 

[PatMiles]

An eye opener.
Going to be a good amount of shooters checking their rifles.
Thanks!

 

[STS]

Great demonstration of ignition characteristics. I'll be he dented the crap out of the cocking ramp on that bolt with the cocking piece.

 

[D-4297]

Interesting information ; but it did pose another question in my mind .
Though my Bolt handle doesn't touch my stock , it does touch the base of the action when closed , but there is slight upward clearance , that allows the Bolt handle to be free of contact of the action . Now ; the question is :
Will the same "reactions" being shown in the video be present , when the Bolt handle is "touching" the base of the action ? Why would there be any difference when touching one , and not the other ?

 

[gunsandgunsmithing]

Interesting information ; but it did pose another question in my mind .
Though my Bolt handle doesn't touch my stock , it does touch the base of the action when closed , but there is slight upward clearance , that allows the Bolt handle to be free of contact of the action . Now ; the question is :
Will the same "reactions" being shown in the video be present , when the Bolt handle is "touching" the base of the action ? Why would there be any difference when touching one , and not the other ?

If it has free travel, it's fine. Think about it...it's gotta touch somewhere. No free travel, and it's doing what Bryan describes...loading the side of the cocking piece in its notch in the receiver.

 

[Tommie]

I pulled my hair out trying to diagnose random flyers with a rifle. Eventually I discovered the bolt was touching the stock. Now I check every new gun.

 

[DLT]

There is a pile of guns if checked by the owner will find the bolts hit the stock.

 

[Chiquita]

There is a pile of guns if checked by the owner will find the bolts hit the stock.

I am checking for sure.

 

[BoydAllen]

More than a decade back, I handled and shot a 6 PPC rifle that had a Viper drop port action. It shot exceptionally well. After shooting it I noticed that the bolt handle made contact with the bottom of its notch in the stock. I surmised that the elevation of the handle that that contact created was not enough to cause a problem. Here is the deal. During actual firing, the forward motion of the firing pin, and with it cocking piece are not stopped by the front of the flange on the pin contacting the inside of the bolt. The primer acts as the stop. One source indicated that the penetration into the primer is about .028. I suggest that if that stopping point falls short of the cocking piece hitting the cocking cam that there will be little effect, at least in the case of glued in bedding. I base this on how well the rifle I mentioned shot. One detail about Viper actions that many probably are unaware of, that Jerry Stiller told me, was that he created additional clearance on the opposite side of the notch from the cam so that there would be no case when the cocking piece would drag. To be clear, if the rifle had been mine I would have removed the contact, but since it was not, and it shot so well I did not want to risk creating what would be viewed as a blemish in the paint, for no functional reason. IMO in a perfect world the bolt handle and its notch in the action need to result in the cocking piece being aligned with the center of the bottom of the cam notch. I have see more than one action where elevating the bolt handle a bit, during dry firing, removed the jiggle that happened it it was dry fired with the handle bottomed in the notch.

 

[RichMoAK]

I pulled my hair out trying to diagnose random flyers with a rifle. Eventually I discovered the bolt was touching the stock. Now I check every new gun.

I am also trying to diagnose some issues with flyers and found your post very helpful. Were you able to tell how much the stock was impeding the bolt closing? 1/16", 1/32", etc.
Also, were there other symptoms associated with this issue? i.e. light primer strikes, wonky ES and SDs, etc. Thanks!

 

[Tommie]

I am also trying to diagnose some issues with flyers and found your post very helpful. Were you able to tell how much the stock was impeding the bolt closing? 1/16", 1/32", etc.
Also, were there other symptoms associated with this issue? i.e. light primer strikes, wonky ES and SDs, etc. Thanks!

It was 20 years ago. I didn’t measure the interference but seriously doubt it was more than a sixteenth of an inch. Likely less. I just used a rat tail file until there was enough clearance.

 

[gunsandgunsmithing]

The bolt handle has to stop on something. Remove the handle and cocking piece..and most bolts would spin 360°. So, I think the point of this thread is more about the cocking piece than it is what actually stops the handle. If you can raise the handle with zero firing pin spring pressure, you're likely fine there. Most will have a noticeable amount of "freeplay" where the cocking piece is not dragging and is just as free as it will be whether the handle stops against the action or the stock. A stock is probably better at dampening any vibration than a metal to metal, bolt to action, contact point...fwiw. But I do absolutely agree with the point of the thread.