Originally Posted by 8x57 Mauser
The RUM cartridges are the longest that I know of, but the 375 is longer than the 300 WM or 338 WM and as far as opening the bolt face, it's already been done on other conversions includu=ing the one I mentioned.
I never discount terminal stupidity as a safety factor. It's amazing what you can find people forcing into their rifles at the range sometimes. While factory ammo won't fit in the magazine of what you're envisioning, I'd think a friend could chamber it with a good hard shove, jamming the bullet well into the lands and back into the case.
That's always possible, but at the same time there are numerous wildcats that this could happen in also. Any one who used my rifle would get a thorough briefing.
If you want a nifty wildcat with your own cool name on it, I'm behind you all the way. That has an indisputable cool factor.
The name really doesn't matter to me, I was just being humorous. But I would have to come up with something and it would probably be something like 300 Montana Mag (I bet that name has never been used....right)
But from reading Murphy's thoughts, and mulling them over, I think this particular idea - the short-throated 300 RUM - would end up with lower velocities than the parent cartridge, and at potentially higher pressures. You may or may not get your acquaintance's accuracy, and you're likely to wear out the barrel faster. Your kids/heirs would have a hard time selling it, too.
Good points here. Not sure why I would get lower velociteis or higher pressures if I kept the bullets off the lands, but then I know very little about the subject. And the throat life is definitely a big question. I'll also be getting the opinions of some gunsmiths here in Montana as well as Dan Lilja's opinion. I would be using one of his barrels.
As far as resale, I figure any custom rifle will be hard to resell. My dream rifle is not likely to be someone elses dream rifle. So I'm going into this for a keeper gun.
For my nickel (and I'm not one of those really experienced people you mentioned), I'd rebarrel a longer action of the sort you want for the caliber you like.