Barrel Torque
- Thread starter peterdobson
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- Oromocto NB
40-50 ft lbs
Remage i think is around 65ft lbs
Remage i think is around 65ft lbs
I usually use 65-70 ft lbs. I just watched a 'smithing video where the guy was insistent on 90 ft lbs though. That said, I've never had one back off. - dan
100 pounds is common, anything over 60 will do. Some do 150.
It is also accepted to snug it up, make a pencil mark on the barrel and recoil lug and then go another 1/8 of an inch.
To remove a factory 700 barrel is another story... and it sounds like a firearm went off when it breaks free.
It is also accepted to snug it up, make a pencil mark on the barrel and recoil lug and then go another 1/8 of an inch.
To remove a factory 700 barrel is another story... and it sounds like a firearm went off when it breaks free.
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The higher the torque, the more the threads distort.
How much "crush" does it take to create a "friction weld" is the query.
I've seen "match" rifles with only enough torque applied that the barrel couldn't be turned off by hand, and they had a few thousand rounds fired before the barrels started to lose to much accuracy and were replaced.
It's up to the individual smith, as we've seen by the posts.
Some torque them to 100+ foot pounds, and use LocTite.
If the threads on the tenon match those in the receiver, IMHO, that much torque isn't needed.
That's where the queries come into it. Threads should all be matching, but in reality, depending on the grinding skills of whomever cuts them, they seldom are. The rule of thumb has usually been about .002 crush, or appx 1/16 - 1/8 inch past snug.
How much "crush" does it take to create a "friction weld" is the query.
I've seen "match" rifles with only enough torque applied that the barrel couldn't be turned off by hand, and they had a few thousand rounds fired before the barrels started to lose to much accuracy and were replaced.
It's up to the individual smith, as we've seen by the posts.
Some torque them to 100+ foot pounds, and use LocTite.
If the threads on the tenon match those in the receiver, IMHO, that much torque isn't needed.
That's where the queries come into it. Threads should all be matching, but in reality, depending on the grinding skills of whomever cuts them, they seldom are. The rule of thumb has usually been about .002 crush, or appx 1/16 - 1/8 inch past snug.
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Obviously we are not gunsmiths but know some competent ones and 220-280ft-lbs must be a joke and using loctite is ill-advised. Many that we have spoken with use 65 in-lbs and anti-seize compound.
Thanks for advise.
Regards,
Peter
Thanks for advise.
Regards,
Peter
FWIW, a new No. 4 Lee Enfield barrel was expected to pull up to index with 120 ft-lb. If you have tried to unbreech a No. 4, you will know that real effort is required.
I have never used a torque wrench to actually measure, but with 2 ft. handles on my receiver wrench, I would be applying 50-60 ft. lbs.
I have never used a torque wrench to actually measure, but with 2 ft. handles on my receiver wrench, I would be applying 50-60 ft. lbs.
Just heard from a world-class gunsmith who says for a standard Remington 700, use 100 ft-lbs, which echoes the experienced guntech comment. This is to ensure that mating surfaces are secure as they are not square. Recommends 80 ft-lbs for trued 700 s and match action/barrels.
A barrel maker advises 60 ft-lbs as "enough" and a high-level TR shooter just graduating engineer, uses 50 on his match actions/barrels. He just dropped off BJ's Viper barrel vice.
A barrel maker advises 60 ft-lbs as "enough" and a high-level TR shooter just graduating engineer, uses 50 on his match actions/barrels. He just dropped off BJ's Viper barrel vice.
With Class 3 threads,
I have several 700's & Barnard P's switch barrel rifles.
Threads cleaned w/acetone.
Threads lubed w/ moly engine assemble lube.
Barrel threaded into receiver & snapped into position (last 1/16th of turn to receiver).
A 3x5 card is wrapped around the barrel & a 12" strap wrench is bumped w/ the heal of my hand to torque it.
Barrel removal is with the 3x5 card & strap wrench.bump..un-thread..done.
I have several 700's & Barnard P's switch barrel rifles.
Threads cleaned w/acetone.
Threads lubed w/ moly engine assemble lube.
Barrel threaded into receiver & snapped into position (last 1/16th of turn to receiver).
A 3x5 card is wrapped around the barrel & a 12" strap wrench is bumped w/ the heal of my hand to torque it.
Barrel removal is with the 3x5 card & strap wrench.bump..un-thread..done.
From Defience:
https://defiancemachine.com/faqs/
Torque is specified by the barrel manufacturer and may vary from product to product.
I cant imagine going wrong following that advice.
Or the averga duck gaining anything by experimenting outside of it.
https://defiancemachine.com/faqs/
What do I Torque My Barrel To?
We recommend you contact the barrel manufacturer and torque to their recommended specifications. We are confident that our actions can handle the torque spec given to you by the manufacturer.Torque is specified by the barrel manufacturer and may vary from product to product.
I cant imagine going wrong following that advice.
Or the averga duck gaining anything by experimenting outside of it.
It would seem to me that basically nobody has bothered to ask WHY a specific torque is specified. I'm not an engineer but I know an engineer and I'd be interested to hear his thoughts on this topic.
Barrels with RH rifling will not unscrew themselves from shooting. The torque the bullet puts on the barrel will screw the barrel into the receiver.
I have a QD barrel system that operates on virtually no torque. It is whatever I can apply to a round barrel with my bare hands. That barrel has never loosened and it shoots reasonably well. It also returns to zero after having been removed. I will admit to being a bit scared the first time I tried it because the notion of a barrel simply screwed in by hand seemed just wrong to me but from years of experience with that rifle, it has never loosened.
Barrels with RH rifling will not unscrew themselves from shooting. The torque the bullet puts on the barrel will screw the barrel into the receiver.
I have a QD barrel system that operates on virtually no torque. It is whatever I can apply to a round barrel with my bare hands. That barrel has never loosened and it shoots reasonably well. It also returns to zero after having been removed. I will admit to being a bit scared the first time I tried it because the notion of a barrel simply screwed in by hand seemed just wrong to me but from years of experience with that rifle, it has never loosened.
There are loads of QD barrel systems that don't use threads at all. They are simply clamped in position and the bolt locks into a barrel extension. Those seem to produce decent accuracy.
There are also many BR quality switch barrel rifles where shooters are changing barrels at the range, using only hand tools. Those are certainly not being subjected to high torque values an they are BR rifles.
There are also many BR quality switch barrel rifles where shooters are changing barrels at the range, using only hand tools. Those are certainly not being subjected to high torque values an they are BR rifles.
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