Thread tolerance/class?

[Antarcticchamp]

I finally got around to trying to install my carbon six 7wsm savage prefit i got fromy last year on my bighorn origin action. After 3 or 4 threads engage it gets hard to turn. I stopped. That's generally how you break things.
My proof-research savage prefit still threads on effortlessly. Multiple barrel nuts thread easily on both barrels.
I don't see any defect on either the action or barrel threads.
Perhaps they and bighorn both use very precise threads? Should I get an action wrench and proceed?
I appreciate any advice you can provide.

 

[shortgrass]

NO! It should thread in easily by hand. Don't screw it in dry.

 

[tobnpr]

Should I get an action wrench and proceed?
I appreciate any advice you can provide.

Hell, NO- don't proceed any further! You'll likely gall the threads- destroying the barrel, and requiring a smith to cut off the barrel to bore out the stub and save the receiver (if you're lucky).

Barrel threads should not be "tight"- slightly loose fit is fine, and is much preferred over a tight fit. This assures the shoulders (or nut to shoulder) can mate up precisely without resistance from the threads.

Assume you inspected the threads on the barrel for damage, foreign matter, etc.?

Sounds to me like the thread pitch on the new barrel is very slightly undersize. Bighorn tolerances are well under a thousandth- it's not their action with the issue.

If you have a micrometer and wires (or of course, a thread mike) you can measure the thread pitch of the barrel tenon, but you're going to need to send it back from whence it came...

 

[Antarcticchamp]

Hell, NO- don't proceed any further! You'll likely gall the threads- destroying the barrel, and requiring a smith to cut off the barrel to bore out the stub and save the receiver (if you're lucky).

Barrel threads should not be "tight"- slightly loose fit is fine, and is much preferred over a tight fit. This assures the shoulders (or nut to shoulder) can mate up precisely without resistance from the threads.

Assume you inspected the threads on the barrel for damage, foreign matter, etc.?

Sounds to me like the thread pitch on the new barrel is very slightly undersize. Bighorn tolerances are well under a thousandth- it's not their action with the issue.

If you have a micrometer and wires (or of course, a thread mike) you can measure the thread pitch of the barrel tenon, but you're going to need to send it back from whence it came...

This is what I feared. This barrel is making a return trip.