Changing the Stock Changed POI Greatly!

[rckendall]

I'll try to keep this brief yet include pertinent information? I have a stock Rem 700 SPS Varmint barreled action in 308. I bought it as a practice rifle and have changed the stock a few times over the last year, always McMillan stocks. My quest has been to learn to shoot as a sniper would: Harris Bipod and sand-sock at the butt.

Last week I went from using a HTG stock (similar to M40A1) to an A-5 and I found that it shot about 4" high and over an inch left! Wow I wasn't expecting a major change like that. I also have more of a faux M40A3 which uses a McMillan A-4 stock. The SPS now feels very similar to the M40A3 type which I expected.

So, now on to the causes of the POI change. Since we know that the barrel oscillates, I figured that the stock must also oscillate, but at it's own rate. Then from that I figured that the HTG stock and the A-5 stock must be at quite different places when the bullet leaves the muzzle. Comments please.

I also decided that I should re-test my load since it shoots so much different. Again, please comment.

Thanks,
Richard

 

[Uthink Uknow]

Is there adequate stock to barrel clearance on all stocks? Did the scope get banged in the change overs? That’s the only causes I could come up with. Are you using a proper fitting action wrench?

 

[dolek]

Have you tried changing the torque on the action screws ?

 

[BenPerfected]

Try running 2-3 pc of paper between the barrel and the stock and see if the paper still has clearance.
Ben

 

[jackieschmidt]

You have aN action bedding problem.

the scope is mounted on the action. Poor bedding will cause the action to literally bend in it’s weak points as it is pulled down into irregular bedding. This can cause the scope to be ever so crooked with the barrel, as it is mounted on the action.

It doesn’t take much. A few thousandths at the action translates to much more on the target.

 

[rckendall]

Thanks for the feedback everyone. I did check barrel clearance with 3 pieces of target stock (.025 total) and all is well there. I always torque action screws in a pillared stock at 65"/lbs.

There may have been bedding issues in the HTG stock as I purchased it used and it was bedded by the previous owner. It did have clearance issues at the lug/barrel area that I had to relieve to get my barreled action to sit squarely.

But from what I saw with the initial testing, it shoots about the same, just with a much different POI. I will test some different loads tomorrow and maybe learn something from that.

Thanks again,
Richard

 

[Dusty Stevens]

A stock needs to be bedded for the exact action thats going in it. And everytime you take it out it gets closer to needing a rebed

 

[rwj]

A stock needs to be bedded for the exact action thats going in it. And everytime you take it out it gets closer to needing a rebed

Would this apply to stocks having embedded metal chassis too?

 

[Dusty Stevens]

Would this apply to stocks having embedded metal chassis too?

They need bedding more than regular “drop in” stocks. Very little contact area

 

[jackieschmidt]

They need bedding more than regular “drop in” stocks. Very little contact area

True, Dusty. And being stiffer, the blocks will also put the action in an even more bind if the bedding is not perfect.

 

[joshb]

New stock=new bedding. No shortcuts.