Screwing on the barrel nut - hand tight or 'factory' tight?

[triggerhappy]

I have a Midway wrench and the instructions say that you should use 30-40 ftlbs, and that is what I used on my first (40ftlbs) and it shoots .25 moa to 500yds. So that is what I am using on my next two I am currently building. It seems to be more than enough torque but not so much that I would have trouble getting it back off.

What caliber and rifle is it that you are shooting 1.25" groups at 500 yards?


I am shooting a 260 rem. with a Shilen barrel using 139gr Lapua bullets. I am so happy with it I am currently working on another with a Lothar Walther barrel I really hope it does as well.

[cgeorgemo]

If you put the torque wrench handle at a 90 degree angle with the wrench, no conversion is needed. Your at the same torque as if you had a socket on it.

If you use the socket square that is closest to the nut the torque will be negligibly different from having a socket on it. If you use the one at the far end you are multiplying your torque somewhat.

[NailsnVail]

Mike Tyson is finding it hard to make ends meet, nowadays. So he picked up a part-time job at the Savage factory installing barrels.

[Hammer]

I expect Savage has a couple of engineers who know how to calibrate a torque wrench so the actual geometry is taken into account. It's physics and mechanics, not magic.




You have more faith in engineers than most. You need to spend more time with hourly workers who have to execute the plans and instructions of engineers.

[amamnn]

I dd not read the 436,789 posts before this so if I repeat please disregard. All you need do is be sure you apply a bit of anti-sieze compound to the barrel threads--thread on the nut, run the barrel into the action until it stops on the go gage you have in there, and tighten using a large crecent wrench on the recoil lug and the SSS wrench on the nut. make it tight, but not ridiculous. To me, hand tight means you used your hands and not tools. I've done 436,789 rifles and barrels in this manner and not one has come loose or been hard to unscrew when a new barrel was needed later. This is not rocket science, people.

[Hammer]

This is not rocket science, people.




It is more important than rocket science.

.

[BobCl]

Then more recently I've seen a few 'Benchrest' types solemnly state that they believe *at least* 100ft-lbs torque makes the guns shoot better, and how they hoped all their opponents only put their barrels on 'hand tight'.
I'm no Savage expert, but I've never seen a "Benchrest" shooter share an advantage! And I'd be real suspicious unless you've actually seen them do it.

[Smokepole]

This can be analyzed as a 'bolted joint' situation. One nut is the receiver, the other is the nut, and the clamped item is the lug, and the barrel is the bolt or stud. The load is the force applied by the blast psi exerted over the area of the bolt head (less the force resisting brass extraction due to brass friction on the walls of the chamber). It's the opposite force as what is applied on the lugs. Each material, barrel, nut, lug, and receiver, will all have a different level of 'springiness' (spring constant). It's related to the effective area of the part, the modulus of elasticity of the part, and the length of the part. The same is said of the bolt or barrel. The preload needed to resist joint separation is all you're looking for. That preload or fastener torque is related to the applied force (the blast), and the effective spring constants of each of the components in the joint. The math is all algebra, but the particulars of the loading and the calculation of the spring constants of each component are pretty hard to get accurately in this case due to unknowns. What's more, the surface finish of the mating parts and the level of lubrication and thread engagement make a big impact on the wrench torque. It's a 25% guess at best since you're measuring indirectly. Fastener preload is best measured by fastener stretch, which in this case would be barrel stretch between the chamber end and the nut. It's not practical to measure such, so we all use wrench torque as a 'best guess'.

As for the comment about engineers; I have full faith in a good engineer. I have little in that of an hourly worker carrying out the directions accurately for a number of reasons. Most of this is to the fault of the worker, due to a lack of knowledge or a lack of care. A lot of it is due to the fact that most engineers have a tough time dumbing down the message enough to get any old Joe to grasp it and believe in it 100%. We're not the best communicators.

A good read in "Machinery's Handbook" or in a decent machine design textbook from a reputable author will go along way into understanding the dynamics of a simple bolted joint. But as you can probably gather from the junk above, the input variables are not easily gotten in this case. I figure the big boys (Savage) have enough time and engineering resources to know what is the best fastening torque. Of course a manufacturer has other motivations, but to err on the best side, I'd go w the 800lb roided out Gorilla tight...

[memilanuk]

Having toured the factory recently... their torque wrench is, as has been mentioned elsewhere, set for something like 87 ft-lbs of torque. There is a short extension on it, but the person giving that part of the tour (Chris Bezzina) said the torque value had been calculated to *include* the extension. He had no explanation for why the barrel nuts are so bloody tight and hard to get off; I don't think it's a problem the factory is all too worried about - their barrels definitely ain't coming off on their own. They did put some thread sealant on the barrel shank (brand = Loctite) to keep some of the finishing solutions from creeping their way in later, but unless that thread sealant is acting as a thread *locker*, or the finishing solutions are getting past it (I have had much less problem getting 'bare' stainless barrels off stainless actions than I have getting 'coated' barrels off coated actions...), dunno.

[RHH]

i have decided that the only time i need to get a nut tighter is when the barrel has a muzzle brake on it.
it seems when i remove the brake( hand tightened but a real good fit ) to clean the barrel i have broke the barrel loose on two different barrels
robert

[amamnn]

100 foot pounds is not a whole lot of torque, actually. I've recently begun using a tool that makes unscrewing a Savage barrel nut --child's play-- I used to soak them in Kroil over night and then grunt and hammer and etc.. but with the new tool--piece of cake-- as a bonus, this tool also can be used to anneal brass with a precision you never imagined-- and it anneals the brass all the way through--No I do not own stock in the company --Induction Innovations-- but I wish I did.

Using a new portable induction heater (mini ductor II) that I bought from tooltopia.com for less than I paid for my complete Ken Light annealing machine, I can now heat up the barrel nut with a directly applied flameless heat, which frees up the nut and makes disassembling a Savage barrel easy as pie. Of course I never have any trouble with barrels I installed because I use anti freeze compound, but that's a different thread.............

[MAGNUS]

Hammer on your "non savage" switch barrel rifles are they set up like the savage with a nut, if not what kind of a switch barrel are they?

[Giturgun]

I have used a Torqe wrench on mine and a friends , But we usually use a resized case , screw the barrel till it stops then turn the nut down . Then I open and close the bolt on a couple of resized pieces of brass . Soon as I get it where the bolt is just barly felt on closing , I peck it with a piece of brass drift a time or 2 . Can change in the stock without taking the scope off this way. It is my way and I am sticking to it. ;D

[ourway77]

On the Belnap sight I typed in Savage nut wrench, Nothing found. anyone ordered one from them to fit thier Savage nut? Lou

[Hammer]

.





Hammer on your "non savage" switch barrel rifles are they set up like the savage with a nut, if not what kind of a switch barrel are they?





Some of my non-Savage rifles use Savage-type barrel nuts -- Remington 700, Weatherby Mark V for 460 and smaller, etc.

The Sakos use something that looks externally like the Savage barrel nut but has two different thread patterns on the barrel - coarse and fine. These barrels can be changed with a lightweight shirt-pocket size spanner wrench without removing the barreled action from the stock. Can change the barrel in the field in under two minutes without removing anything but the barrel itself. Have one Sako with barrels ranging from 264 Win Mag to 470 Capstick and another Sako with 22-250 up through 375-06 Improved.

The Rugers, the Weatherby Mark V in larger than 460, and some others do not lend themselves to the barrel nut approach -- mostly from an aesthetics point of view. These use no barrel nut and use a regular shouldered barrel. Several barrel makers have my particular actions blueprinted and have CNC computer programs made for these specific actions so that I can order additional barrels without sending them my actions for final fit. New barrels fit perfectly when delivered.

McMillan and some others keep custom CNC programs for their fiberglass or other synthetic stocks to match my barreled actions and their idiosyncrasies. Again, that way I can order additional stocks without sending barreled actions for fitting and the stocks fit perfect when they arrive.

The majority of my guns have free-floated barrels, but some do not. With swap barrel guns free-floated is the easiest way to go.

Scope base and mount systems need to be standardized across lots of actions and be quick-detachable (what quick-detach means can be a fun debate). On a single action may have half-dozen different scopes to use in a single day depending on the use, the specific shot, the rifle barrel being used, etc. But the same scope may be switched between multiple rifle actions too.

It can get tricky if you're using one specific barrel on multiple actions. Don't recommend that for most people. Too much cost involved in initial setup of the actions.

Swap barrels on calibers like the 500 A-Square, 550 Magnum, and 585 Nyati get tricky due to the need for barrel mounted additional recoil lugs and the perfect matching of them to stocks. Some might argue that on a particular trip to Africa you shouldn't be switching from the 550 to the 585 in the middle of a cape buffalo charge, but others will suggest it is important to have exactly the right gun for the specific charge.

One wouldn't use a 222 Remington Magnum with a 13-inch twist on a bull prairie dog when the situation called for a 222-1/2 Remington with a 12-7/8 - inch twist -- would they ?


These are the most common types of switch barrel methods that I use.


Life can be fun.




.

[MAGNUS]

Thanks for that Hammer ;D

[axaviere]

this guy has a neat approach for switch barrel rifles

http://www.lprgunsmith.com/lpr_switch_rifle.htm

[axaviere]

hey, optics panet has nut wrenches on sale for $27. order a pack of $2.99 targets and get the free shipping on $30 or more orders

when i was putting my barrel back on, i had the headspace set, put the barrel in the blocks and went to tighten the nut. the nut, lug and receiver spun all at the same time. i had to reset the HS and im wondering if i should put the receiver in blocks and clamp that with the vise instead of the barrel? anyone using any lube on a stainless barrel going into a non stainless reveiver? thanks

[axaviere]

i put the receiver in the blocks and set the nut to 50 ft lbs. it all went smooth after i had the right tools. i made a vise from stuff i had laying around.

http://farm3.static.flickr.com/2788/4425422377_7ca5007b81_b.jpg

the blocks from SSS had two sets, one for heavy barrels and one for smaller contours. i used a rasp to hog out the blocks to fit the receiver. drilled a hole in one block and used a bolt in the action to anchor the receiver... im sure this is old hat for most, but its my first bolt, first barrel swap, so its all been a learning experience for me.

http://farm3.static.flickr.com/2792/4426195268_192a46faf6_b.jpg

anyway, 50 ft lbs its all good.

[Tozguy]

Factory tight is my choice. There is more to the question than just making it easy to remove the barrel next time. The barrel/receiver threads need to be preloaded enough to prevent movement in the joint under the loads of firing. May mean choosing the right thread lub and different torque values for different calibers.
Anyone have 'official' instructions from Savage?