Action alignment in a stock

[Rich S]

I was helping a friend investigate tracking issues with a stock. It is a very beautiful laminated benchrest stock. We set it up on a mill and indicated in the bottom of the forearm. In the process we found the forearm and buttstock were close to being parallel to each other. The action inlet, barrel channel and top of the stock were all parallel to each other however were not parallel to the forearm/buttstock. The action/barrel channel and top of the stock all angled down from the start of the action inlet to the forearm ~0.030"/in compared to the bottom of the forearm. All of the inletting I have completed on flat bottom stocks, I made the action parallel to the forearm/buttstock. It is apparent this stock was intentionally made with this alignment. I was wondering if this was common with some stock makers or if there is a good reason for this.

 

[Dusty Stevens]

It has to do with recoil driving it into the bags. Its some pretty advanced stuff the br gunsmiths do when they inlet and isnt discussed too much.

 

[Alex Wheeler]

If the top of the stock angles down towards the front compared to the bag riding surfaces thats called drop. By your description you have and equal amount of drop in the forend and butt (st-1000s are designed like that). So as the rifle recoils it drops equally, unlike a rifle with drop only in the butt. You cant see this in the scope, as the entire rifle is dropping so little its unnoticeable to the eye. Some of the idea is that as the rifle recoils the bag surfaces pull away from the bags and reduce friction. Id say thats true based off of the increased recoil I can feel with that design. Your tracking issues are not that. Your bag riding surfaces need to be dead nuts parallel not close.

 

[Rich S]

Thanks for the reply’s.
It is actually a laminated ST1000. It is a well made stock and it appears they held all the lines clean and accurate. We did find about the last 1 1/4” of the forearm had extra drop. My assumption is there was some extra sanding when it was finished. We plan to adjust where it rides in the front bag to verify. If that doesn’t correct it, we will likely skim the surfaces. We would have done that to start but it has such a nice finish we hate to disturb it.
Are there any standards or rules of thumb for how much drop a stock of this design has?

 

[Alex Wheeler]

You can skim the surfaces and put a bunch of time into it and get it close, or you can make a rudder or front plate thats adjustable and get it dead nuts. So far as how much drop, theres no rules for it in long range so you can do what ever you want. I have made them with a lot of drop, more than the ST, and parallel.

 

[jackieschmidt]

It has to do with recoil driving it into the bags. Its some pretty advanced stuff the br gunsmiths do when they inlet and isnt discussed too much.

The barreled action on my 30BR, built on a Robertson Stock, is actually angled up so it tends to drive the rear down, avoiding that annoying hop that the rear can exhibit when shooting free recoil. You can visually see the upward angle of the barreled action.

You have to be careful when doing this because too much angle, and the rifle will not fall in the guidelines in the rule book as laid out for aVarmint Rifle.

 

[Dusty Stevens]

Exactly