I have about 40 cases for this wildcat 1960s
cartridge. It is listed in PO Ackley's Vol. 1.

Someone went to a great deal of trouble with this cartridge to get higher 7mm velocities. It is a fully improved 348 case with no taper. Med long neck with ID at 7mm-could easily be used as a 8mm or 30 cal version. Finally, the rims are turned off to be used presumably in a bolt action rifle.

{If you have an interest in these cartridge cases=
shoot me a PM) R Marriott

i think these are also called the H.E.M. high energy magnum .. developed entirely independently and prior to the RUM/WSM mania

quote:

Originally posted by jeffeosso:
i think these are also called the H.E.M. high energy magnum .. developed entirely independently and prior to the RUM/WSM mania

I was thinking the same same thing. Weren’t those first developed like back in the 50’s. I am completely ignorant of patent law, but I find it strange Jameson’s patents held water when the H.E.M.’s had been around for so long.

As a callow lad in the early 60's my hunter safety course instructor, with whom I became lifelong friends, one day mentioned he had come across a new large 7mm rimmed cartridge that he thought was really going to take off. Sounds like the one being discussed. He showed one to me and described it as the "7mm Gradle", built on a very improved .348 case. At least that's the name I remember; who knows how Gradle might have been spelled and it might have had 'express' tacked on to it as well. He was a 300 H&H shooter but he sure was enthused about that chunky rimmed 7mm Gradle.

Matt,
interesting question .. one of the basis of rick's position is that his is a 2 to 2.65" long improved 404 as new art -- it should have fallen as prior art existed - and minor dimensions don't generally make new art ...

copyright i could have seen, btw.. but tightly defined

I thought the 7mm Express was when Remington briefly renamed the 280.
It caused some confusion with some ignorant owners who couldn't figure our why 7mm Rem Mags didn't fit their chambering.

Zeke

Steve:
You are on the correct path. Roy Gradle near Ventura, CA. developed this cartridge which is similar to the Wade Super 7 in AZ-Wades Gun Room-Phoenix.

The Gradle version, which I believe these to be-uses a venturi shoulder like the Weatherby cartridges. This is a highly refined wildcat. It produced velocities similar to the 7mm Rem magnum in the 1950s. The late 1950s produced some hot
wildcats and PO Ackley's Vol 1 gives the details.

These 348 imp cases are very close in capacity of the WSM rounds. Whether made rimmless or with the rim they are quite powerfull. I built a 375/348 Ackley Imp on a Siamese mauser action. With bullets up to 270 grs it is 100 fps or less behind the 375 H&H out of a 3 inch cartridge. Heavier bullets must be seated deeper and case capacity is compromised.

A long range lever gun, has always been a quest and the 348 case was the only real donner perhaps..but today the Browning Lever actions is available in a 7 mag, 300 mag and 338?? better options.

I would think the rimmed case IMP 348 would be nice for a Ruger #1 #4 barrel..but 348 brass is damn hard to come by and very expensive if you find some. I dont see it as a bolt action round, too many other good options, and a caliber only an extremeist wildcatter would even consider. Just my take on the subject..