I am starting to load 30/378 for a factory Weatherby rifle. I have been told that there is some "freebore" in factory Weatherby chambers, so -- do I measure it and set the depth just like other standard calibers, or is there some other trick to figuring seating depth in these rifles? Any help or suggestions would be greatly appreciated. Larry B.

Larry: I've worked with Weatherbys a lot and you do have to take the long throat into account IF you want to equal factory loads. The way I started, I just took a loaded factory round and measured bullet OAL and loaded mine the same, with the SAME bullet type, i.e., I used 180gr Hornady or Nosler, the same as the factory loadings. You really have to be careful not to seat the bullet to close to the lands with hot loads, if you do, youu'll get pressure signs real pronto!

If you can get a hold of one of the old Weatherby Guides, there is a wealth of loading data in there, even one that equal factory offerings. The down side is that the last issue was 1982, so if the powder, bullet or caliber is newer, it won't be listed. Practically all of the reloading manuals are real conservative even on their max loads, but anytime you work with max loads, you need to first throttle back and work up. jorge

If you set the bullets close to the rifling in a gun with freebore they will most likely not fit in the magazine.

This is where a bullet comparator comes in handy. Measures from the bullets ojive, not OAL. If in doubt, follow a recepie from any reputable source until you develop the skills/collect the necessary tools to do all of it yourself.

I've been loading the 30-378 weath now for over 2yrs. The free bore in my Mark IV does not allow me to load while .0010 from the lands. If I do this then my rounds will not fit the magazine. What I have done is load to a max. magazine length. This has worked well for me. I have tried almost all the slow burners, H 4831--IMR7828 RL22-H 1000-H 5010--H 870, and find that only the ultra slow burners work well. H 4831 and IMR 7828 work not too bad but only with the lighter bullets. My favorite load so far is 200 gr Nosler Part, 114grs H 870, Fed 215 and an OAL of 3.790. With this load vel runs 3246 fts/sec. NOTE: Barnes manuel has their 200gr at a max load of 118 grs of H 870. In my rifle I can't come close to this load. 114grs is the aboslute safe max load in my rifle and this is with a conventional constructed bullet that normailly allows a grain or two more powder when compared to Barnes bullets . A word to the wise concerning this caliber is start low and carfully work up always watching for pressure. I have found that due to the ultra vel generated by this round only premium bullets should be used in the game fields.