I have an acquaintance that is a competitive shooter and avid and very experienced reloader, and is probably known by several people that post on this forum, so I'm not going to use his name. Anyway, he and I were talking recently about the differences in ballistics between the 7mm Weatherby Mag and the 7mm Remington Mag.
He noted that the Rem actually has a grain or two more case capacity than the Wby, when measured to the BASE of the neck. He also said that the only differences between the two that accounted for the increased velocity of the Wby (with same bullet) is that the Wby is loaded to higher pressures and that there is a little more freebore in the throat of Wby barrels. Ok, sounds plausible so far.
He added that the freebore was really a non-issue because he'd seen the Wby chambered in standard throated barrels and they shot Wby ammo and loads just fine with no excess pressure signs. Hmmmm, I thought, I'd like to see one of those rifles and its fired brass for myself. If you bought a Wby reamer wouldn't it have the Wby freebore already cut into it??
THEN he said that because of the slightly greater or equal USABLE case capacity of the Rem Mag, that, in modern rifles, you could often safely work up Wby Mag velocities in a Rem Mag by using Wby loading data in the Rem. He said that the Rem Mag loading data had been "wimped out" and toned down by SAAMI due to "weenie lawyers" over the years. And that the Wby ammo was loaded to European standards which are much more realistic as to what is truly "safe". That back in the day the Rem ran neck and neck with the Wby. I decided to check out some of that.
I've got loading data and manuals going back into the 50's and I dug it out, especially from the 60's and 70's, and found some of what he was talking about. I also have the Speer manual that very clearly states in it's section on the 7mm Rem Mag that the rifle they had previously used for testing their loads had an eroded throat and the previously published data was too hot for a normal rifle.
This is the same guy that turned me on to the "fact" that you can use 416 Wby data to soup up a 416 Rigby, as if my shoulder could stand it.
I'm not going to lie and say that I haven't exceeded the maximum shown in loading manuals by a grain or two a few times IF there were absolutely NO pressure signs and the chrono data looks good and stable. But, I've never exceeded published data by the amount of the differences shown in most manuals between the 7mm Wby and Rem.
His statements intrigue me, but they also sort of make me want to move several benches away when he's shooting his Rem. Anybody with any experience doing this? Is he playing with dynamite?
