Hi

I read a article written by Geoffery Kolbe about the development on pressure and throats dimentions. www.border-barrels.com

A very common thought is that you need to seat the bullet far of the lands if you have a magnum cartridge because of the pressure!!

Lazzeroni, Jarret et. al. seats their bullets very close to the lands as many other target shooters, custom gunsmiths, handloaders. I find it hard to belive that you would need to seat the bullet very far from the lands to achive more velocity. The extra gas you get by more powder must slip by the bullet before it goes into the lands.

Cheers
/ JOHAN

I think they might be talking about freebore. Like the Weatherby's throat. Essentially, the freebore acts like an extended cartridge case, giving effectively more volume. This is what allows the higher velocities. For example, the 7mm Weatherby is only a tiny bit larger in volume than the 7mm Rem Mag. But the Wby round has much higher velocity, because with the freebore, there's more room for powder expansion. You can burn more powder at equal pressures (larger area). Of course, Wby ammo is loaded right to the max as well. FWIW - Dan

I believe the far seating of bullets is to create a pressure curve that rises quicker.