How much can a bolt shroud impact accuracy?

[JBradley500]

I have 308 Bergara B14 Hunter and it grouped like crap. I called Bergara to ask if they had any possible issues they know of. They asked about the age of my gun because they had a problem with cast bolt shroud threads basically stripping/backing out. Mine looks like it was backed a thread or two after one box of shells and the threads have flat spots on them. This problem also seems to have kept the cocking indicator from going back to totally line up the hole you use to insert an Allen wrench when removing the shroud.

The tech for Bergara seemed very confident this would impact my groups and sent me the new style shroud that fixes the problem but I haven't gotten to shoot it yet since this covid stuff. I didn't think much about it, but now I'm not sure how this impacts accuracy besides possible cocking/firing pin force. My primer strikes all look the same to my eye. Is there more that the bolt shroud does that can impact accuracy? Thanks.

 

[bsnedeker]

My understanding is that it has to do with the alignment of the bolt with the rails and chamber. Since the lugs on the bolt hold onto the base of the cartridge if there isn't perfect alignment of the bolt your cartridge and bullet will be misaligned with the barrel causing inaccuracy.

That's what the guy who sold me a "performance shroud" for my gun told me anyway! Lol!

 

[Newtosavage]

where's my flag...

 

[wyo2track]

Remington 700's equipped with the infamous j lock bolt shrouds were known for contributing to inaccuracy. There were articles wrote on it. I bought a lightly used 7mm saum with one and replaced the j lock shroud for an aftermarket with a much straighter and stiffer spring. Made all the difference in my opinion in improving accuracy. If the shroud itself is backing away from the bolt body and the spring is resting on the shroud wouldn't it affect how the firing pin is contacting the primers from shot to shot?

 

[Wapiti1]

A loose, worn, or otherwise unhappy bolt shroud can change how the bolt aligns somewhat randomly, and affect how the cartridge sits in the chamber also somewhat randomly. There is always misalignment of the bolt and cartridge. What is important is that it is misaligned the same every time you chamber a round. Ever wonder why seating depth matters? This is one reason why.

It may not cure your issue, but should help.

Jeremy