Bolt Shrowd Modifications..

E

eww1350

Guest
The bolt shrowd is primarily a guide for the cocking piece as the bolt is roatating into battery...what kind of modifications are being done to reduce the cant, drag of the shrowd on the action and the cocking piece on the shrowd...these are the biggest contibutors to irratic ignition...I would like to hear comments from members that have made modifications to address the problem...
 
Well...any bolt shrowd..the Remington, Stolle, Shilen, Stiller, Borden, Hall, Nesika all have thread in shrowds...and each work in the same manner...I have heard that some smiths are making modifications to the shrowds..just don't know what those specific details are...it would make sense to install delrin or similar material plugs into the lower flats of the shrowd to center it and remove metal to metal drag that it has on the right side...


Eddie in Texas
 
Famous name gunsmith does just as you describe to Remington shroud flats. An earlier thread discussed shroud thread fit. Some shooters have reported that tightening thread fit has helped accuracy. In cases where it was too loose. In some cases teflon tape was used to good effect. For the bottom flat work to work properly the bolt needs to have a good fit in the rear action bridge. Some have modified the hole that the firing pin goes through (in the shroud) to reduce the potential for binding. While you are at it, check for cocking piece drag in its slot in the tang, the corners of the trigger side plates, and along the straight side, opposite the cocking cam, and it's centering in the bottom of the cam cut.
 
I know little or nothing about this but I've heard of Rem shrouds being machined from Ti, aluminum, steel, Delrin and other unknown synthetics. I've seen steel and Delrin. I've played with teflon tape, steel shims and thread fit. I've formed no opinions other than that certain well-made Bench Rest actions, actions designed and purpose-built by Engineers who understand the parameters, work very well. One I've some little experience with, the Borden, is redesigned front to back to eliminate certain drag/misalignment/capture problems inherent to the 700 design.

I've idly pondered the idea of reversing the threads, using LH threads at the rear of the bolt.

Maybe these speculations will goad some of the posters who KNOW about this stuff to answer :)

(Although were I one of those 'in the know' I don't know if I could find anything to say in a limited format like a BRC post......)

al
 
I don't think there is a common fix for all bolts and shrouds. Many of my customs have been pretty good and only required minor work. Remingtons are notoriously the worst.
The threads at the rear for the shroud are rarely on axis and centered. Given the best
shroud made, that crooked thread tilts the firing pin into a bind somewhere. What has worked for me, is disassemble the firing pin and reassemble it without the spring. By
pressing on the shroud in different directions and pushing the pin into fired position, you can
generally find the bind. IT should fall very free. Along the way, its not hard to find another
dozen issues in remington bolts
 
Al,
Those of us who shoot left bolt, with actions that have RH threaded shrouds, already have what you ponder. BTW it is my belief that for the advantages of using opposite thread handedness to bolt handle side to be fully realized, the threads need to be timed so that the shroud to bolt gap closes to minimum clearance, when the handle is down. Personally, I think that if the thread fit is right, there is little to be gained. John Illlum, designer and builder of the Rampro actions, paid a lot of attention to this detail. The gap closes to nothing.
 
My 'old reliable' Time Precision ALV HV rifle, was made "that way" (RELIABLE) by Jim Borden: the work included working-over the bolt-shroud, and installing/milling 'guides' on the bottom surfaces, which keep the 'twisting/binding', relative to the action-way surface, to a minimum. The action bore was also re-worked, to remove a taper, and the bolt-body was bushed to fit nicely in the re-bored bolt-way. The combination of Mr. Borden's 'tricks' turned this action around 180 degrees! Prior to Jim's magic, the action wore three stocks, and five barrels, no combination of which produced competitive AGGING.:mad: Following Jim's 'conversion', this action has yet to wear a 'bad' barrel, and still sits in that third stock. I cannot say that any ONE attribute turned this action around, however, the combination of Jim's efforts, bolt-shroud modification included, made this action a real 'keeper', with super slick operation, it remains my favorite HV rifle.:D My last two action purchases were Borden RimRocks, and needed zero tampering with - they simply work! :cool:RG
 
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