How tight should the barrel be?

[qkshot]

I was wondering how tight should the barrel
be torqued on the reciever. I am looking for some specifications.

1. a factory barreld bolt action
2. a rebarreled bolt action by a smith
3. a switch barrel gun
4. a semiauto 308 rifle with custom barrel
5. a light weight moutain rifle
6. a 50bmg bolt action
I assume they would all be close but not
quite the same specs.

I ask because what is the most safe and accurate way to install a barrel on the above mentioned recievers. I have read a 1/8 to 1/4 turn past hand tight but i have not seen this in real practice and i was wanting to know from somebody out there thats been doing it for awhile.

Also what is the benchrest crowd doing
for torque it would seem the least amount possiable to get the job done. less stress
means less warping when everything heats up
but where is that line between perfection and not acceptable.

Thanks in advance for the info

SDR


sdr.

 

[sniper2]

I have never heard of torque on barrels, most are threaded very tight any way. I have screwed on half dozen with good results, the ones I tried were very tight by the time the proper head space was reached.

 

[JBM]

Harold Vaughn's book, "Rifle Accuracy Facts" , has an entire chapter on "Barrel-Receiver Threaded Joint Motion" (starts on page 103). He shows that a barrel that is not torqued property will move slightly. He also shows examples a couple of different kinds of threads, e.g. the Spiralock Ramp Thread", to ensure that all threads are equally loaded (due to stretching of the threaded portion of the barrel).

He tests this new thread with a barrel torqued to 200 ft-lbs using teflon tape as a lubricant and it eliminated flyers on his rifle.

The book is available from Precision Shooting, (860) 645-8776.

 

[Victor N TN]

SDR,

I'll by no means an expert. But I've been shooting a switch barrel rifle since 1996. I got my second benchrest rifle w/ 2 extra barrels last fall. Here's the way I do it.

I clamp the barrel in a good barrel vise with a paper wrap between the barrel and vise. Usually a paper towel roll or a cut up old file folder. After removing the present barrel, I wrap the threaded end and put it in a barrel bag. (Home made, my wife used to like to sew.) I clean the internal threads of the receiver with chemical naptha, or regular lighter fluid. Make sure you clean the face of the receiver where the barrel will lock up, and the mating area of the barrel. After checking the new barrel for burrs and dirt on the threads, I apply a small amount of anti sieze compound to the end few threads. (A spot about the size of a green pea.) I use the FelPro / LocTite brand C5-A copper based formula. After screwing the barrel back into the receiver up to just bump the stop. Then I place the receiver wrench into the action and give it a healthy smack with a large dead blow hammer. But not too hard. If I had action wrenches that were the rear entry type that a torque wrench would fit. I would probably have a more precise way to tighten the barrel.

I hope this helps.

Victor www.johnsonprecision.net

[ 06-20-2004: Message edited by: Victor N TN ]

 

[JayIdaho]

FWIW.... A new barrel with good threads and a true shoulder being put on a custom action or trued-up Remington is torqued to about 70 ft.lb. by me. I chose that number because it "felt about right" and I want to be consistent. More or less will probably work fine.
I have seen a barrel (not one of mine) loosen up at a 1k match, the shooter was not happy.

 

[kidcoltoutlaw]

i have a hart switch barrel gun they said it will snap in place when i get to the right spot as im putting the barrel on.how tight do i tighten the barrel vice it also is a hart rear entry.i don't want to damage the barrel by over doing it with the barrel vice,thanks,keith