Custom barrel rifling

[sh3rm4nt4nk]

A friend was talking about custom barrels.
He said some weatherby barrels are free bore for a short distance before the rifling starts and it increases velocity.
He ordered a barrel that has a graduated twist rate, increasing as it goes.
I've never heard of either and I'm wondering if any of you use these and how well do they work for you?

 

[Afy]

I have heard of a graduated twist rate, just never have seen one.

 

[NCsmitty]

Here's some good reading on custom barrels. It's called gain twist rifling. I believe Italy used it on their Carcano milsurp rifles.

http://www.riflebarrels.com/articles/barrel_making/details_of_accuracy.htm

NCsmitty

 

[gvnwst]

One time you need gain twist is with certain borerider type bullets, and when you get large bullets to super high velocitys. I have never used one with standard bullets, but IIRC, the reports say it is just fine, with accuracy comparable to a "standard" barrel of similar quality.

 

[BADUNAME27]

Gain twist barrels have been around a long time. Great idea only it just doesn't seem to work all that well.

Have yet to see one on the firing lines at the competitive events or in the hands of military precision rifles.

That should tell you something. . .

 

[Strongbad]

The 460 S&W uses a gain twist barrel (just a side note).

As for the freebore on the Wby, it
is really more about reducing pressure than it is about velocity. The velocity comes from more powder.

 

[sh3rm4nt4nk]

Thanks for your responses. He also mentioned over stabilization vs understabilization. The first being that the bullet remains at the angle it was fired from rather than pointing in the direction of travel as it arcs. The second a wobble. It sounds like good theory but in the end it will be trial and error that finds the right weight and length of bullet and charge combination.
If I ever get enough practice/ training to shoot sub moa I might look for a custom barrel. Right now my rifle is alot more accurate than me