Barrel to action torque?

[Rflshootr]

Give me some more info...what caliber? what twist?.....How many rounds so far?....What powder, primer, brass and bullet. Where are you seating the bullet in relation to the lands? How often are you cleaning? Is the lug pinned to the action face?

 

[J E Custom]

Just My experience with torquing a barrel.

The first thing you must do Is true the mating surfaces. (square the receiver face to the bolt center line. I like to do all the action truing before I start the barrel threading and chambering so that I can Fit everything to the barrel as I go.

The barrel tenon threads are fitted to the action for a close fit (No slack) and the bolt head clearances are cut at this time.

When everything is fit properly the chambering is started. Head space is determined and .001 thousandths is calculated into the total head space for tenon stretch or compression depending on the type of action to barrel fit. after chamber completion
rarely does the .001 get exceeded if the threads are fit to the action and all mating surfaces cut square.

I like using anti-seize or thread lube so there is no galling or abrading of the threads during torquing that could alter the make up clearance and head space. It also make the torque more predictable and repeatable. Disassembly is very easy when a thread lubricant is used instead of a thread locker.

What I have found is that if all the mating surfaces are square and clean before assembly, and thread lubricant or anti seize are used, No misalignment occurs.

J E CUSTOM

 

[Raschiller]

Great post!

What thread lubricant do you recommend?

 

[Mram10us]

This usually breaks into a "does clearance in the threads between action and barrel affect accuracy?"
And, how much is too much?

 

[Joefrazell]

Give me some more info...what caliber? what twist?.....How many rounds so far?....What powder, primer, brass and bullet. Where are you seating the bullet in relation to the lands? How often are you cleaning?

It's a 9 twist 300 win mag. 175ish rnds. 215 Berger is what I want to shoot. I've tried h1000 and imr 7977 also h4831sc. Also I've tried 200 eldx, 212 eldx and 180 gr ttsx. Win brass, .002- .003 neck tension, cci250 and fed 215m. I tried .030 off the lands on the eldx bullets. Also tried .020-.040 with the 215 hybrid. I just cleaned the barrel but usually don't clean but every 100-150 Rds or so. Usually clean and lube bolt every couple of outings. Hope this helps.

 

[Rflshootr]

OK I'll make a suggestion based on my 300 mag. But first make darn sure that you have the recoil lug located correctly and the your bedding is good. Go with the 215 if that's what you really want to shoot. Go with either the H4831 or the H1000, whichever seemed to shoot better on your previous attempts. I shoot Winchester Mag primers, but the Federals should be fine. Make sure your sizing die is set correctly. Remove the firing pin assy, back the die off and try the case in the chamber. The bolt should close with a very slight resistance. After you're sure your die is set correctly, check your trim length. I would start with the bullet just barely touching the lands and a starting load for whichever powder you pick and work up in .5 grain increments. I'd also do 3 shot groups to start to save on bullets. If it won't shoot 3, it won't shoot 5. I have also found that custom barrels shoot better clean then when they are dirty so I'd recommend cleaning at 20-25 shot intervals with a light coat of oil in the bore for the 1st shot after cleaning. I hope this helps. Let me know how you make out. The bedding and lug position IS important.

 

[J E Custom]

Great post!

What thread lubricant do you recommend?

This is one of the best that I have used and it is specially for torquing threads. There are others But I like products that are designed for the service to be used. I have also used Anti seize with good results, but at this time this is my favorite.



J E CUSTOM

 

[Joefrazell]

OK I'll make a suggestion based on my 300 mag. But first make darn sure that you have the recoil lug located correctly and the your bedding is good. Go with the 215 if that's what you really want to shoot. Go with either the H4831 or the H1000, whichever seemed to shoot better on your previous attempts. I shoot Winchester Mag primers, but the Federals should be fine. Make sure your sizing die is set correctly. Remove the firing pin assy, back the die off and try the case in the chamber. The bolt should close with a very slight resistance. After you're sure your die is set correctly, check your trim length. I would start with the bullet just barely touching the lands and a starting load for whichever powder you pick and work up in .5 grain increments. I'd also do 3 shot groups to start to save on bullets. If it won't shoot 3, it won't shoot 5. I have also found that custom barrels shoot better clean then when they are dirty so I'd recommend cleaning at 20-25 shot intervals with a light coat of oil in the bore for the 1st shot after cleaning. I hope this helps. Let me know how you make out. The bedding and lug position IS important.

Please explain the lug position to me?

 

[Rflshootr]

If the stock was bedded with the lug in one position and it is not in that position now, it is possible that it is not making correct contact with the bedding. Most smiths relieve each side of the bedding on the mill when finished to help alleviate that problem. I use a tool that screws to the bottom of the action that traps the lug in a slot, so each time a barrel is removed/replaced/reinstalled, it comes back to the same spot. Or another way is to pin the lug to the action face.

 

[Sam Summey]

What do you mean by stress the barrel .004? Are you talking .004 on the threads or pulling it out of alignment .004 at the muzzle? Thanks

A properly torqued barrel will stretch the barrel threads thus affecting head space ~-.004. Sorry for the mis-information (spell check) changed my wording. Grizzly Tool has a video on barrel chambering/fitting and rifle building that is very good with the dynamics of tightening barrels. I watched a rifle being built at the S.H.O.T. Show the gunsmith doing the work was very explanative and knowledgeable.

 

[Sam Summey]

A properly torqued barrel will stretch the barrel threads thus affecting head space ~-.004. Sorry for the mis-information (spell check) changed my wording. Grizzly Tool has a video on barrel chambering/fitting and rifle building that is very good with the dynamics of tightening barrels. I watched a rifle being built at the S.H.O.T. Show the gunsmith doing the work was very explanative and knowledgeable.

BTW the 22-250 barrel was not even tightened and had excessive head space. If a barrel has to be removed from the action the gunsmith should make a "witness mark" on the barrel and action so the barrel can be reinstalled in the same position as before.

 

[Joefrazell]

If the stock was bedded with the lug in one position and it is not in that position now, it is possible that it is not making correct contact with the bedding. Most smiths relieve each side of the bedding on the mill when finished to help alleviate that problem. I use a tool that screws to the bottom of the action that traps the lug in a slot, so each time a barrel is removed/replaced/reinstalled, it comes back to the same spot. Or another way is to pin the lug to the action face.

Yeah the lug is pinned to the action face on this particular build

 

[Mram10us]

A properly torqued barrel will stretch the barrel threads thus affecting head space ~-.004. Sorry for the mis-information (spell check) changed my wording. Grizzly Tool has a video on barrel chambering/fitting and rifle building that is very good with the dynamics of tightening barrels. I watched a rifle being built at the S.H.O.T. Show the gunsmith doing the work was very explanative and knowledgeable.

I have never had a torqued barrel adjust more than .002" of the headspace. Where are you getting the "properly torqued" barrel specs?

 

[Sam Summey]

I have never had a torqued barrel adjust more than .002" of the headspace. Where are you getting the "properly torqued" barrel specs?

This was a piece of info shared by the Grizzly gunsmith, over and over again. In addition, when I retightened the barrel on the above mentioned 22-250 the .004 of excessive head space was eliminated. The barrel was essentially a little more than hand tight. BTY even after re-tightening it has never shot as good as it did before being removed from the action.