Barrel blueing

[WESTERNAERO]

Finished machining my new barrel (moly) and was getting ready to send it out for blueing. I was wondering if I should have the ends plugged so the rifling and chamber stay unblued. Or not to worry about it and have them blue it inside and out. Thanks.

 

[sdeering]

Do not plug. The barrel is dunked in 295deg. salt bath. Makes for pressure inside blowing out the plugs.
Stephen

 

[WESTERNAERO]

Thanks Stephen.

 

[shortgrass]

That new bluing in the rifling will be gone with te first shot! Parkerizing or the coatings (GunKote, CerraCoat,DuraCoat) are the only time I plug bores when finishing. The coatings would 'shoot out', most likly, with the first shot. Not sure what that might do to pressures as it is a coating and has thickness, although, a slight thickness (.0001 or less maybe). Parkerizing etches the metal so the inside would be a no no for sure. Probobly more than you wanted to know, but, for your next project!

 

[Clark]

When I cold blue, I plug the barrel with rubber stoppers, and turn the barrel on the lathe as I rub it in.

I got a [factory blued up the bore too] Douglas long chambered 260 barrel with Mauser threads.
It has been a long hard haul to break in that barrel.
It does a couple moa groups and then the flyers start.
The muzzle then looks Copper fouled.
I clean the copper out with KG12 and Flitz.
Then it is back to moa groups.

 

[WESTERNAERO]

My concern about blueing the inside of the barrel wasn't about coating thickness. It's more about the rusting process that happens. I was wondering if in a match grade barrel where the rifling has been honed or polished that it might be best not to let the corrosion process take place there.

 

[shortgrass]

If the barrel was left in the tank too long , yes, then etching might occur. Blued properly, the parts should come out of the tank as soon as the depth of blue desired is achieved. The operator should then make sure and flush the bore to make sure all the salts are out and then send it into a boiling water bath for 15 minutes or so flushing the bore some more, by picking one end up and letting the water run all the way out. Then to a tank of water displacing oil. Bluing adds no thinkness so it won't increase pressures. Clark, yours sounds more like a Douglas problem than the fact that it's blued.