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Ruger Precision Barrel Swap







#2
You might just go ahead with them , my buddy who’s a rifle builder /smith won’t touch the Ruger precision rifles because the barrel nuts are beyond tight & he’s broken a few wrenches trying to remove them . How much are they charging to swap barrels ? I have a 6mm to swap also in the near future .
 

Janizary

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#3
...because the barrel nuts are beyond tight & he’s broken a few wrenches trying to remove them

WTH? Those use AR-type barrel nuts, right? What kind of wrench is he busting getting that off? I've gotten a couple of red loctited bbl-nuts off idiot AR builds with a good quality wrench (I like PRI for stubborn standard AR bbl-nuts). Holy cow that really makes me wonder what they are torqueing those to, or what they are using on on the threads (or if they are using anything...which could very well account for it, hmmm...)
 
#4
Yeah man ... Im told they are tightened by the silver back gorilla of the troop ... no idea what wrench he’s busted up but enough that he won’t attempt another . I remember him saying they would tighten the nuts on the magnum actions with the torque wrench till it maxed out then backed it off a click or two ( no joke) I have a few RPR’s & gotta find somebody who will swap barrels too 🤦🏽‍♂️
 

Janizary

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#5
Okay, I took a look at this video of a barrel swap and see what the issue is. It has both a handguard nut (read: normal AR15 barrel nut) AND a gawd-awful internally threaded barrel nut. The AR barrel nut mounts to the Ruger barrel nut, which is, in turn mounted to both the barrel and receiver via 3 threadings (threaded for AR bbl-nut for rail mounting, internally for the barrel, and an external extension for the receiver). Yikes.

Recommended torque for the actual barrel nut is apparently 70ftlb, but who knows if they are using any anti-seize or what it may have come torqued to from the factory.
 

NYECOGunsmith

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#6
Okay, I took a look at this video of a barrel swap and see what the issue is. It has both a handguard nut (read: normal AR15 barrel nut) AND a gawd-awful internally threaded barrel nut. The AR barrel nut mounts to the Ruger barrel nut, which is, in turn mounted to both the barrel and receiver via 3 threadings (threaded for AR bbl-nut for rail mounting, internally for the barrel, and an external extension for the receiver). Yikes.

Recommended torque for the actual barrel nut is apparently 70ftlb, but who knows if they are using any anti-seize or what it may have come torqued to from the factory.
Generally speaking torque specs are based on diameter, pitch, material, internal or external thread, lubricated, galvanized or dry fitted.

For most barrel steels, using the 1"x16 TPI thread that Ruger uses, if it were lubed with Anti-Seize it would be torqued to about 85 Foot pounds, fitted dry, no anti seize, no wax, no lube at all, it would be torqued to about 120 FT Pounds.
There really is no need for any thread locking compound on a barrel's threaded shank, the radial force exerted against the thread engagement between the barrel shank and receiver only serves to set the male and female parts of the thread together tighter, it doesn't try to loosen them. To do that would require both a radial force and a axial force at the same time, in a helical vector if you will.

Over tightening threads leads to thread stretch and that can lead to failure under load, in a bolt / nut or bolt/threaded hold situation where there is a load axially on the bolt or the nut, but that's not going to happen in a rifle barrel.

Tighten a barrel to the factory (or barrel maker's ) recommendation, making sure they quote a spec for using Anti Seize, (and then use the anti seize!) and call it good.

Too loose or too tight can lead to axial misalignment, and that's one of the causes of inaccuracy in a rifle.

Everything has to be as perfectly in line coaxial with the bore, as close as possible that is.
The firing pin , firing pin tunnel, bolt in receiver, bolt locking lugs square to bore axis, bolt face square to bore axis, receiver face where it contacts barrel shoulder square to bore axis, the receiver threads square to the bore axis, the barrel shank shoulder square to bore axis, the chamber centered in barrel, bore centered in barrel , etc. in order for maximum accuracy and repeatability of that accuracy.

If a barrel doesn't come loose with the expected amount of reverse torque (which is generally about 20-25% more than the specified torque for tightening it) heat the barrel shank up at the receiver with a hair dryer set to high or a heat gun.
This expands the male threads on the barrel into the female threads in the receiver and then when it cools, they contract, having broken some (if there is any) corrosion or galvanic bonding between the two.
Then heat the receiver up at the barrel / receiver junction, and cool the barrel with ice or a blast of compressed air.
Now you have created as much space between the two as possible, and, if the barrel was secured with thread locker,
it should have lost most if not all of its grip,

So while the receiver is hot and the barrel is cold, and of course you started with an empty gun and you have the barrel locked securely in a good barrel vise, turn the receiver off the barrel.
In some cases where some gorilla went nuts with the torque and thread locker, you may need to heat the receiver at the barrel up , and liberally soak it with KROIL® or a 50/50 mix of ATF and Acetone, might have to do that several times, then with it hot/cold, use a cheater bar on your receiver wrench, first trying to tighten the receiver ever so slightly, then immediately reversing direction and taking it off.

Slight tightening often crushes any remaining corrosion or thread locker and creates that last bit of space so the threads will spin apart.
 
#10
Dropped the rifle off to the gunsmith. Received a call 2 days later that he wouldn’t be able to do the swap because he didn’t have the right tools.
I’ve since found DNA Tactical ($200/10 days) and Loaded Chamber ($65/14 days).