Truing threads for bolt shroud?

[boltfluter]

Hey ignition specialists,

Has anyone ever recut the bolt shroud threads in a factory Remington bolt to straighten them out. Many I have seen are actually quite bad as far as straightness and concentricity are concerned. Seems like this could cause the firing pin to drag during firing. I have a .22BR that is prone to misfires in extreme low temps when coyote hunting. Just thinking out loud. Looking forward to your thoughts and ideas. If you guys think there is any validity to this theory I will make a new shroud with over size threads.

Thanks, Paul

www.boltfluting.com

 

[RWO]

if you time is worth anything, it's a lot easier to just buy a new shroud. PTG has a large variety: http://pacifictoolandgauge.com/84-remington-700-shrouds

RWO

 

[boltfluter]

if you time is worth anything, it's a lot easier to just buy a new shroud. PTG has a large variety: http://pacifictoolandgauge.com/84-remington-700-shrouds

RWO

RWO,

I don't think you are grasping what I am saying. If I true the threads in the bolt body, then the threads will be over size. Hence the need to build a shroud, unless someone makes one
with an over size thread.

Paul

 

[BoydAllen]

Tony Boyer has described a test for determining if there is a binding problem between shroud and firing pin. The reason that I mention this is that it would seem to be quite a bit of work to recut the bolt body shroud threads and make a matching shroud. He described assembling the bolt and striker assembly without the striker spring and then pushing the shroud up, down, and to both sides, as he tipped the bolt so that the striker would fall and return. So far, I have not found a bolt that failed this test, but it is easy to do, and should relieve your mind as to whether you have a problem. Another issue can be fit of the shroud in the bolt. Speedy asked Dave Kiff to make oversized shrouds to deal with this, and they are available as a regular listed item, the part that that is oversized, and which may require fitting (I have not tried one.) is not the threads but rather the smooth cylindrical section immediately behind them. I have also experimented with teflon tape on the threads to take up the slack. One fellow who posted here fond that he was able to cure erratic accuracy on a custom action that way. It turned out that that particular action has been made with a loose shroud thread fit, something that I have observed on an old 722 action of mine. The difference in the the sound of dry firing, with and without the tape is quite noticeable. I should mention that the fellow whose problem was solved by using the tape had an identical rifle that did not have the problem. Its shroud clearance was tighter.

 

[geo.ulrich]

Paul, Yes I have done some, would prefer a p.m. on this one .....George

 

[ireload2]

When you have a series of coaxial diameters inside a part like a bolt body it is likely they were all machined at the same chucking.

That means that the firing pin tip clearance bore, the bores for the firing pin flange and the firing pin spring are all off axis like the threads for the bolt sleeve.

If they are all off you might want to consider getting a new bolt that is straight inside and out.

When you fix the threads for the bolt sleeve the rest of the bores will be offset to the firing pin. You might be able to ream the clearance for the firing pin spring oversize but the hole for the firing pin tip would be hard to move on center. The distance from the back of the bolt to the bolt nose might let it work at an angle.
That is not what you want in an accuracy rifle.

 

[geo.ulrich]

so you think the firing pin hole is drilled from the back, nope. and all the other inside diameters other than the threads are just clearance or should be...

 

[Dans40X]

Fit the threads to class 3 in bolt body & shroud.
Work hardened 360 brass bushings.
30-32 finish throughout.