Weatherby magnums always had a belt on the case, and you will note none of these modern large cartridges are belted. Headspacing off a belt doesn't work near as accurately as headspacing off the front shoulder of the case (and using cases that are neck sized only after being fired in your own gun's chamber so they are a custom snug fit).
But then you are likely gonna need a longer stronger bolt camming action to cam the case out after firing it once again on a moderately hot round ....
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My first pistol was a cap and ball Remington Italian copy. Still got it as a matter of fact. It was a blast to shoot at night (threw a cone of sparking smoke filled nasty that would night blind you it was so bright and showy). You could actually see the cylinder flash out past the barrel cylinder junction .... your hand was plumb buried in fire for an instant there buddy.
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No, all I've actually said so far in response to direct questions is that it isn't a belted magnum and the small one is tipped with a 154 grain 7mm bullet and fits into a standard sized rifle. Given that you should be able to figure out what the short one is and then use that to project a reasonable guess as to the bigger one.
Then again, few our age are real gun nuts any more -- although it seems to be a lot more popular among young people than you might think. They grew up with shoot'um up video games and when they hit 14-16 they started buying airsoft replicas and then they YouTube themselves doing head shots on deer and silly stuff like that when they hit 18 and can buy a real rifle and go hunting.
Gun culture seems to be doing fine -- there are far more guns, types of guns, pistols, etc now than there ever have been.
And it does seem to ring true the same ones also ride dirt bikes & mountain bikes when young, too. Guess what they become .... us
Women support pistol use quite a bit now (the great equalizer) and the largest indoor range and gun store in Raleigh NC is owned and run by a woman and has women only concealed carry classes where she teaches women how to (and when it is permitted to) pop the bastard instead of letting him rape you.
Go girls, go !!