I am having a rifle rebarreled to 257 Weatherby by PAC-NOR. It is my understanding the rifle is not going to have any freebore like conventional Weatherby rifles. I understand that I will most likely not be able to shoot factory rounds through this rifle. What I have been wondering is what percentage from maximum should I reduce my initial loads to when I begin load development?

10% reduction in powder charge is a good rule of thumb when dealing with the Weatherby (or any hyper-velocity) magnums.

You still might get very good velocities at 'reduced' levels, due to the excellent interior finish of the Pac-Nor barrel.

Good luck, and let us know how your rifle turns out.

George

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Shoot straight, shoot often, but by all means, use enough gun!

As I recall, Bob Hagel was getting higher velocity from his 340 without freebore, then from his std chamber with freebore.

I wonder if anyone on this forum owns rifles in the same caliber with and without freebore that would be able to shed some light on the subject.

Bill from what I understand I should achieve higher velocities at lower loadings but I'll have higher pressures also, that is why I am curious about the starting point.

After some insight from some other forum members, tossing and turning all night, and talking to PAC-NOR this morning I have decided to go with the Weatherby specs. Everyone seemed to feel I was robbing the cartridge of potential energy and velocity by not having any freebore. I want to get as much as possible from the round. Everytime I have talked to PAC-NOR they have been great..I highly recommend them to anyone!

WELL WELL

I had a 257 WBY with custom camber. There is a very interesting report about freebore and pressures at border barrels web site. Geoffery Kolbe has a PhD in Physics, so I think we can relly on his work. www.border-barrels.com

My rifle shoot great with 0.3 millimeters of the lands. All this bullshit about miles of free bore pisses me off. Lazzeroni has not very long between the lands and the bullet.

I started with the a few grains above Normas minimum load and worked my way up. Long free bore is a "cover my ass insurance" from the manufacurer since "John Doe" might never heard of solvent and gun care, or carefull reloading. Go with the custom camber, if you don't like the rifle send it back for reaming to standard. IF YOU DON'T HANDLOAD GO FOR THE WEATHERBY CAMBER!!!

Sniper, I know you have lost a lot of sleep over this. I would have to agree with JOHAN on this one. I would go with the shorter freebore. I haven't seen much or any loss of velocity potential with a shorter freebore. I have seen an increase in accuracy potential by being able to get closer to the lands. Like JOHAN stated if you go with a short freebore and you find you can't get the velocity you are Looking for it is very simple to extend the freebore. It is much more difficult to shorten it. But, if the longer freebore will allow you to sleep at night go for it.