I have a Browning 1885 in 7mm Remington Magnum with a Leupold 4.5x14 50mm scope. When I bought this combination, my intent was to have it re-chambered to 7mm X .300 Weatherby for more velocity.

I bought new .300 Weatherby cases and RCBS dies for the the wildcat and sized the cases. I don't have an outside neck turner, so I haven't finished prepping the cases.

Upon developing loads for the standard 7mm magnum cartridge, however, I found that I could drive 175 gr. Sierra SBTs and 195 gr. Barnes SSPs to 3060 and 2850 fps from the rifle's 28" barrel, respectively. I also found the recoil as hard as I wanted it, at least from shooting on a bench.

Those velocities are not far lower than the larger 7mm cartridge velocities, which almost invariably have 2" shorter barrels. Not long after I bought all that, the new 7mm STW came out in factory rifles, and cases are available for loading.

I am reconsidering having the rifle re-chambered to one of the larger 7mm cartridges, now that I have a home-made lead sled. Do any of you have experience with either of these longer cartridges and/or considerations I might not have thought of?

http://i86.photobucket.com/albums/k101/Silliamii/PICT0001copy.jpg

To muddy the waters, you could also have your 'smith to chamber for the 7mm/375 Ruger and have the same 7mmx300Wby and 7STW peformance...

I've shot the old 8mm Rem mag for years and shoot a friends 7mm STW which is the 8mm mag case necked to 7mm. The 7mm Ultra-mag has a bigger case along with the 7mm by 378 Weatherby which has even a little bit bigger case.

The problem is bullets at the velocities your shooting these at don't usually perform well at closer ranges. Deer shot under a hundred yards tend to end up with lots of blood shot meat, even a 7mm Rem mag will do that at close ranges with 140 and 150 grain bullets though.

The only thing I'd say is go for the 7mm RUM, no case forming to do and maximum velocity from a factory case. Bullets and brass is available and it's really hot. It's a larger case than the 7mm STW and you can buy standard dies and brass.

Alaska Man, I once purchased a 7mm STW but was unimpressed with the velocity verses amount of powder I was burning etc. Why my model 70 Winchester .300 magnum was out shooting that rifle using 150 grain bullets. I traded off the 7mm STW for another rifle!

If you want more velocity pushing those larger 7mm bullets, I would look hard at getting yourself a much bigger case for starters. However, this is only going to increase the recoil to the upper torso, there is "no cigar" when it comes to shooting large bullets fast.:)

If you want more velocity pushing those larger 7mm bullets, I would look hard at getting yourself a much bigger case for starters. However, this is only going to increase the recoil to the upper torso, there is "no cigar" when it comes to shooting large bullets fast.:)

I believe that part of the reason the larger 7mm's fail to impress compared to the vanilla 7mags is due to the shorter barrels than I have on the 1885 (28"). I realize, too, that there are other imperceptible differences in barrels that make identical barrels shoot differently.

On average, the full-length, blown-out .375 H&H case that the STW and .300 Weatherby use should produce about a 150 fps gain over the standard length 7mags. In my barrel, that would probably give 3210 fps with the Sierra 175gr. SBT, and 3000 fps with the Barnes 195 gr. SSP.

Those would be some smokin' velocities for those bullets! They would also generate more recoil than I want to tolerate shooting from a bench. That's why I made a lead sled. Practicing from a standing or other off-hand shooting position would probably be alright.

I am not worried about recoil when actually shooting at an animal in the field. I don't notice even .388 recoil when I shoot at a living target.

I am primarily concerned with the relative merits of the two cartridges in question, or lack thereof.