Hello all, thanks in advance for any replies.

Anyway, I have a 1917 Enfield action made by Remington that I've been thinking about working up into a 375 caliber rifle. I constantly hem and haw between:

375 H&H
375 JRS
375/404 Jeff

I tend to lean toward overbore a bit such that I have long-range capability with stiffer loads but I sure like the idea of shooting standard 375 H&H loads if necessary. By saying that I'm looking for something between the two extremes which is why I mentioned the 375 JRS.

My question quite simply is whether or not standard 375 H&H loads will chamber in a 375 JRS?

In terms of measurements, the A-Square manual lists case dimensions as follows with H&H first/JRS second:

Case head to shoulder: 2.412/2.398
Case head to start of neck: 2.498/2.487
Case length: 2.85/2.85
Trim-to-length: 2.84/2.84
OAL: 3.6/3.6

Although many case dimensions are identical, the first two referenced show differences of 0.014 and 0.011 respectively, with the H&H being slightly longer leading me to believe that if standard loads do chamber it would be with some effort.

Your comments are appreciated and I would desire even moreso personal experience.

Thanks,

Reed

You might do well to consider the .375 Weatherby also.

Reed,

Have you considered the .375 H&H Ackley Improved? A simple fireform using standard off the shelf ammo. In the event your ammo is lost, you can walk into most stores and find .375 H&H ammo. Better performance over the standard version and the JRS. Doesn't require any more of a modification to the action than the standard H&H chambering. Doesn't require the extent of modification as one based on the 404 case...

Just a thought to keep the others company.

Malm

I have a mauser chambered for the 375JRS. Simply shove in common 375 H&H and pull the trigger. Mine is superbly accurate with 270 grain Hornady's and a hefty charge of IMR-4064. My barrel was a rebored from a 7mm Rem Mag and was done by the late Sam May in Arizona. He was a superb barrelsmith and is greatly missed. I had mine done in the early 90s and he charged $85 for the rebore and rechamber. Some metal butchers charge four times that now and claim quality. He delivered. But I digress. The 375 JRS is a great cartridge and 2900fps from the 270 grainer is fairly easy. Recoil isn't bad.
Doug

375 JRS, 375 Ackley, and 375 Weatherby are all improved versions of the 375 H & H and can all have 375 H & H ammunitione fired in their chambers. The only one of these with factory ammo available is the 375 Weatherby if that matters to you. Ballistically, they're all peas in a pod. - Dan

I like the standard .375 H&H chambering. If I wanted a hotter .375 I would just go the whole hog and get the "stallion" the .378 Weatherby, built on a cz at about 10.5-11 pounds with big pad and good stock it would be fine and you would have a real long range hammer.

Out of an Enfield the 378 Weatherby may cause problems in terms of using the magazine. I know my 338/416 Rigby on an Enfield is a single shot as the loaded rounds are too long to fit into the magazine without major modification to the magazine box.

I suspect this may be a problem if using long pointed bullets. Ironically enough, those are used for long-range work.

I'm not necessarily looking for the fastest option here as I already have pretty good performance out of that 338/416...300g bullet at 2900fps. I'm looking more for a 375 hunting rifle that could be hopped up with formed cases if I desire.

FWIW, I kind of like the idea of chambering standard 375H&H loads into a rifle that has an improved chamber. I guess there's the possibility with that extra slop that it may bind somewhat upon feeding but I tend to think it will be that much better for chambering.

I think I know what I need to know. Should I go through with this it may rely heavily upon which reamers my gunsmith has available.

Thanks for the responses.

Reed