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Barrel torque vs precision?

jccinohio

I recently 'upgraded' the action to a Mack Bros Evo II on my Rem 700 .308 Win Remage & torqued the barrel to 50 ft lbs. I believe on the Rem 700 action I had it at 40 ft lbs... anyway. Same barrel.. It seems to shoot my 110gr (Note 1) reloads about the same, but doesn't seem to shoot the 175SMK FGMM near as well, and not too happy with my 175SMK reloads either (1"+ at 100yds.). Does barrel torque have an effect on tuning?

Note: only shot 6 of them as my stock is LOW and my new Varget is much different than my old; over 100 fps for same load, and precision seems not as good with the new stuff.

Got the new action for the 308 so I could use the Rem 700 action on a 243 build.
 
Sounds like you've combined a number of changes here. I doubt that the different torque is causing the problem. If the barrel has a different number of threads into the new action to get the headspace you need that might change the 'sweet spot's. You could try some different powder charge weights to see if it helps.
 
If the tenon threads are square, barrel torque will not make much difference. I torque my F- Class barrels to 65 ft/pounds.

I would say the change is do to how the new action interacts with the stock as well as the velocity difference with the new lot of varget.
 
ShtrRdy said:
Sounds like you've combined a number of changes here.
Click to expand...

Right, too many things have changed to expect it to be the same.

I used to play around with action screw torque and seeing how my 700's groups changed; this was back when I used an AICS chassis. If that can change a group, why wouldn't changing the whole action? I take it that it's not bedded? It might be worth a test to put it back at 40 and re-test the groups.
 
gunsandgunsmithing said:
I won't agree or disagree but will say that I haven't seen indexing change tune. Wouldn't it be the same as saying that the tune would change if you shot the gun upside down? Hypothetically, of course.
Click to expand...
Gene Beggs came up with a setup that would allow indexing a barrel wherever you want, without rechambering it. Perhaps you remember it. It could be used with a 700 size action with normal to hot loads with .223 head diameter cartridges. For his system the barrel tenon was turned smaller by enough so that there was a piece over it that was threaded to match the action on its outside, and for the tenon on the inside. This insert was shorter than the action threads so that it could be adjusted in and out so that the location of the thread start could be changed. I believe his tests showed an effect on accuracy from different index positions of the same barrel, but it has been a long time since I read about it.
 
BoydAllen said:
Gene Beggs came up with a setup that would allow indexing a barrel wherever you want, without rechambering it. Perhaps you remember it. It could be used with a 700 size action with normal to hot loads with .223 head diameter cartridges. For his system the barrel tenon was turned smaller by enough so that there was a piece over it that was threaded to match the action on its outside, and for the tenon on the inside. This insert was shorter than the action threads so that it could be adjusted in and out so that the location of the thread start could be changed. I believe his tests showed an effect on accuracy from different index positions of the same barrel, but it has been a long time since I read about it.
Click to expand...
Although that would be a fun experiment, the amount of rotation caused by torquing a barrel 40 ft/lbs vs 50 ft/lbs is negligible.
 
Both torque numbers seem quite a bit light.....significantly lighter than what I'm torquing my shouldered barrel to on my Mack Bros action.
What's Mack Bros. recommendation? Don't forget that you're also 'seating' their unique recoil lug.
 
jccinohio said:
I recently 'upgraded' the action to a Mack Bros Evo II on my Rem 700 .308 Win Remage & torqued the barrel to 50 ft lbs. I believe on the Rem 700 action I had it at 40 ft lbs... anyway. Same barrel.. It seems to shoot my 110gr (Note 1) reloads about the same, but doesn't seem to shoot the 175SMK FGMM near as well, and not too happy with my 175SMK reloads either (1"+ at 100yds.). Does barrel torque have an effect on tuning?

Note: only shot 6 of them as my stock is LOW and my new Varget is much different than my old; over 100 fps for same load, and precision seems not as good with the new stuff.

Got the new action for the 308 so I could use the Rem 700 action on a 243 build.
Click to expand...
Did you rebed it? The answer could be as simple as that.
 
I don't think the barrel torque will alter much.if the barrel shoulder-action face is square 70 lbs/ft is more than enough,any more your just stretching and stressing everything.i would make sure the bedding is right-stress free.then try tuning your reloads.good luck.
 
Everything is the same except the action and the torque. Stock is a KRG Whiskey 3. The 100fps difference in the varget was determined prior to changing the action. The only known/proven load I have is the 110gr v-max reloads (with old lot of varget), and they grouped around .5 MOA with old and new action. I didn't try to develop a 175 gr load in the old action with the new varget. Rifle shot an old batch of factory FGMM to well under .5 MOA. Never shot any of my new FGMM with the old action, and in the new action I only shot 5 and it's getting 1+ MOA.
 
BoydAllen said:
Gene Beggs came up with a setup that would allow indexing a barrel wherever you want, without rechambering it. Perhaps you remember it. It could be used with a 700 size action with normal to hot loads with .223 head diameter cartridges. For his system the barrel tenon was turned smaller by enough so that there was a piece over it that was threaded to match the action on its outside, and for the tenon on the inside. This insert was shorter than the action threads so that it could be adjusted in and out so that the location of the thread start could be changed. I believe his tests showed an effect on accuracy from different index positions of the same barrel, but it has been a long time since I read about it.
Click to expand...
I was in the shop of a barrel maker who's name you would recognize when a barrel was finishing being drilled. I was quite surprised to see the hole in the end of the barrel was clearly off center when they were finsihed drilling the hole.

I asked about it and was told once they profile the barrel, you can no longer see that it is off center. Problem solved. LOL

Has this changed?

If not, the ability to index the barrel would be of interest.
 
Ruger15151 said:
If the tenon threads are square, barrel torque will not make much difference. I torque my F- Class barrels to 65 ft/pounds.

I would say the change is do to how the new action interacts with the stock as well as the velocity difference with the new lot of varget.
Click to expand...
That seems really low. I was taught to torque to 100-110ft-lbs and I’ve used that number on all my rifles since and it has served me well.
Dave
 
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