I am loading some ammo for a friends 30-378 Weatherby. I know that most Weatherby rifles (its a Mark V) have freebore to lower pressure. In most of my rifles I load the bullets as close to the lands as possible. That doesnt look like an option in this case due to possible increased pressure. Should I start with the max overall length from the manual to develop a load?

Forget getting close to the lands. With 180gr Nosler Accubonds I use 3.76". With 180gr Partitions I use 3.745".

It would help to know what bullet you are using.

Though not a 30-378 the loads I build for my 338-378 I split the difference between factory length and max length using the 225 grain Barnes TSX. I've found this load to be more accurate then the factory ammo and within a few fps of the same speed. It's not a max load either. The factory freebore is long enough that it is next to impossible to get all the way to the lands but if you find the bullet you are using can get pretty close you'll need to reduce the load. The nice thing about the Mk V design is you won't blow it up if you are WAY over pressure but it's not a good idea to exceed max for any period of time.

Ken....