The 375/348 Ack Imp that I have been working on this past winter is finally comming together. After clening up the the Siamese mauser action (previously owned by someone name bubba). Drilled and tapped for scope mounts ,installed a new bolt handle and opened up the bolt face. New handle was Tigged on, (bubba had tried to braze a handle on???). I had Harry McGowen chamber the barrel for me, # 3 ,24 inches long. I put this in a Richards stock and glass bedded the action and first 3 inches of the chamber area of the barrel. still lots of sanding and the checkering to do but that will come later. Tried the first fireform loads last night. That went well. Cases came out with nice sharp shoulders. This should make quite a med range (2-250 yds)thumper . Can hardly wait to try it on a black bear or a moose this fall.

Checked case capacity of the fireformed 375/348 Imp case against std 375 H&H cases. Rem brand 375 cases held approx 95 grs of W760 powder to fill the case level full . The 375/348 case held 89 grs. This is going to be closer to H&H ballistics than I first thought with bullets weighing 270 grs or less. I suspect heavier bullets will consume too much case capacity.

Are you thinking perhaps about 2550 fps. with the 270 gr. bullet? That's over 3800 ft.lbs of Energy. That's a good bit for sure roger

I was hoping to test several of the lighter 375 cal bullets. 270 gr would be the heaviest I would use (I think). I also wanted to try the 260 gr Noslers and the 250 Sierra bullet.Any of them should be good for black bears and moose. Should also be good for deer & elk in the bush.The 235 gr Speer bullet should also work at closer range. A 250 gr bullet @ approx 2600 fps or a 270 gr @ 2500 fps will be somewhere between 3700 & 3800 ft/lbs as you have pointed out. I plan to use 4320 and RL15 to start load developement. While the mauser action is strong there is no sense in pushing the pressure up too high.

I almost hesitate saying it, but if you have any 7383 this would be a safe cartridge to use it and get reasonable performance. Just a thought. roger

I would start with 376 steyr loads, myself

Jeffeosso Good idea. Anyone out there have a 376 case? how many grains of W760 will the case hold when filled level to the case mouth?