Minimum Barrel Shank Length

[Clint E.]

When chambering a centerfire bolt action rifle with a sporter contour barrel is there a minimum length required for the straight cylindrical portion of the barrel? Does the chamber need to be cut completely in the straight cylindrical portion of the barrel? If not how much of the chamber can be in the tapered portion of the barrel?

Thanks,
Clint

 

[Blastattack]

Minimum cylindrical length is thread engagement. The chamber can easily be cut into the tapered section, provided you taper is not too steep, and your cartridge neither too long nor too large. This here Ross is chambered in .303 British, and I do not remember the diameter of the barrel, but it is very skinny.

 

[bigbull]

The diameter ahead of the shank is what is important , the shank can be major thread diameter if the barrel is fitted up against an internal shoulder ala Mauser but usually there are two shoulders with a 98, the M70 FTW has a very short shank but the barrel ahead of the shank is almost shank diameter and then quickly tapers to the FWT barrel profile. The only shortcoming is getting a good grip for barrel installation or removal on a rapid taper.
BB

 

[bearhunter]

Barrel taper after the threaded shank, will depend on the cartridge being chambered.

IMHO, the taper shouldn't start for at least 3 inches after the shoulder. This makes for a much stiffer barrel/receiver lock up and of course, not lonely gives you some meaty area to grip in the blocks but provides a very good bedding area ahead of the recoil lug or collar.

That being said, I once built a 30-06 and a 6.5-06 on Rem 700 actions with the taper starting right at the receiver. It wasn't an extremely sharp taper for the first 6 inches but enough to give a very sleek appearance and shave off a bit of weight. The rifle was built as a light weight sheep hunting rifle. The contour was slimmer than a factory barrel but not by much. It shot quite well for the first 3 shots and started to heat up pretty quickly after that.

Take a look at Remington Model 7 rifles, with pencil thin barrels. Their taper starts right at the receiver.

 

[buckbrush]

the "Featherweight" taper of Winchesters has about 1/4 to 3/8 of an inch of shoulder sticking out of the receiver, it was also used on the 88 Winchester. Frank DEhAAS book "Bolt action Rifles" has quite a few different barrel shank and shoulder drawings, the best book for them is the NRA's "Gunsmithing Guide"