Harmonics problem....(I think) Ideas??

[Deputy819]

Morning Gentleman! Having an issue with my .338-06 and need some ideas on where to start "trouble-shooting" so as to avoid just groping around in the dark. It's a Savage 110 (originally .30-06) that I rebarreled to a .338-06 and had the factory stock both pillar and glass bedded (Devcon). It's a hunting rifle and it consistently shot 1-1/4" groups at 200 yards, but recoil and muzzle rise was substantial. So, instead of putting a muzzle brake on it (like I probably should have) I had my Smith put it in a much heavier Bell & Carlson stock with pillars and Devcon glass bedding. I also figured "what the heck" and had the barreled action cerakoted and the whole thing turned out great. One problem though.....Now it wont turn out anything better than 2-3" groups at 200 yards. None of my previous PROVEN hand-loads work (SD/ES below 10) and I'm at a loss. I've tinkered with seating depth and powder charge with no success. Action screw torque is at 65" lbs front and rear, both barrel and tang are free-floated and all scope base and ring screws are torqued to proper factory recommended specs. Would cerakoting and changing stocks affect a rifle in such a dramatic way? Let's hear it....

 

[AZShooter]

IMO the stock change is your issue. The easiest thing to try is less action screw torque.
Start as the linked article says @ 30 in/lb.

http://www.accurateshooter.com/technical-articles/savage-action-screw-torque-tuning/

Some possible issues from my documents:





If either action screw is a blind hole: check for bedding material or screw bottoming out


forward most scope ring base screw touching threads of barrel.



Action screw holes in stock too small, drill larger so sides of action screw won't touch


Bolt handle touching stock


Mag box must not bind


Recoil lug could be making early contact in bottom of bedded slot

causing the action to sit off bedding


Front of trigger group must not touch stock


Trigger guard must not touch trigger


Uneven bedding--- tightening one action screw to see if the action pulls up at other end.


Barrel should not make contact with barrel channel in front of bedding. Due to some flexing some rifles required additional material be removed from stock.

Be sure to let us know what you discover. If you are reluctant to try some of these things bring it back to your gunsmith for an inspection. It shot before you switched stocks perhaps the two of you can figure out what changed.

 

[Deputy819]

The easiest thing to try is less action screw torque.

Oops...neglected to mention that I had also tinkered with action screw torque a little bit. Not quite sure how to "read" the results though. Here you go...

 

[Capt RB]

Bell and Carlson use a bedding block in their stocks. Your smith should not have put pillars in it for starters. Check your fore end to make sure your not touching the barrel channel while in the shooting position. Meaning if you use a bipod or use bags check with the dollar bill. If it is really close you may have the barrel contacting due to whip as the bullet is still in the barrel during firing.
Why would you float the tang? If you had a skim bed done correctly it creates a longer surface for greater stability when done.
Check to make sure no ceracote got on the lug surfaces, Check the bore and crown also.
Check to make sure your firing pin fall was not changed when the bolt was stripped to be coated. If put together wrong the pin will move in and out due to the lock washer not being in the correct orientation. Or may be short making inconsistent ignition due to lack of force. This sounds like it may be the issue if everything else checks out

 

[Capt RB]

Oops...neglected to mention that I had also tinkered with action screw torque a little bit. Not quite sure how to "read" the results though. Here you go...
View attachment 110153 View attachment 110154

Run the lug side higher than the tang side and make sure the bottom of your lug is not touching any bedding material

 

[Deputy819]

@Capt RB
I posted this a while back and never got a response. Bought this stock off another member on LRHM and my Smith said it was an OLDER model Bell & Carlson stock. It has pillars, but no aluminum bedding block. It's not the prettiest, but it's heavy and is very comfortable.

https://www.longrangehunting.com/threads/anyone-recognize-this-brand-make-of-stock.207615/

I'll check the things you mentioned as soon as I'm through hunting this morning. Smith also said that Savages shouldnt be bedded in the tang area. That may or may not be true. I honestly dont know....

 

[Capt RB]

@Capt RB
I posted this a while back and never got a response. Bought this stock off another member on LRHM and my Smith said it was an OLDER model Bell & Carlson stock. It has pillars, but no aluminum bedding block. It's not the prettiest, but it's heavy and is very comfortable.

https://www.longrangehunting.com/threads/anyone-recognize-this-brand-make-of-stock.207615/

I'll check the things you mentioned as soon as I'm through hunting this morning. Smith also said that Savages shouldnt be bedded in the tang area. That may or may not be true. I honestly dont know....

The floating of the tang is common for standard hunting tapers if it is a heavier barrel I'd rethink it for sure. Good luck both today and with the solution

 

[Deputy819]

Magnum contour....tapers to .75 at the muzzle.

 

[gohring3006]

I would be suspicious of the bedding job.
Make sure the mag box isn't binding.
Nothing touching the trigger assembly.
Make sure the front action screw isn't touching the bolt, not even a tiny bit.
A good bedding job can make a rifle shoot great, you can also do a bad bedding job and ruin the accuracy.
I like to float the nut, some I've seen don't. I've seen both work.

 

[Hand Skills]

Ahh, the dreaded "2 and a flier". It appears the groups vary with torque, so I think you're on the right track with bedding.

@Alex Wheeler has a good video on how to test your bedding.

 

[Deputy819]

@Hand Skills
@gohring3006
I was thinking more of a possible bedding issue than anything, but will still check the other recommendations. My smith has done at least 4 bedding jobs for me in the past and all have performed well. Thats not to say he cant make an error from time to time, though. The groups definitely vary with different torque values. I made sure that all my hand-loads put through it were as identical as possible so that the only real variable changing was the action-screw torque. Really hope to get this rifle up and running again soon. This week-end was our gun-season opener for deer and has been my GO TO rifle for the last 3 years. So far...NOT this year. Thanks fellas!

 

[Alex Wheeler]

The first thing I would do is put the old stock back on and shoot it.

 

[xsn10s]

I had used older B&C stocks and haven't had good results with them even after skim bedding. They are better than injected molded stocks. But I've had problems with shifting in the stock even after bedding. I'll go with Alex's suggestion of going back to the original stock. It's an easy check to get a baseline accuracy.

 

[Deputy819]

@Alex Wheeler
@xsn10s
Excellent idea!! Good thing I kept it in the safe. I'm notorious for throwing things out that I "dont need".