i was chatting with someone the other day and we got onto the subject of ackley improving a 375.

can it be done, i didn't think there was enough shoulder to be able to ackley it?

any of you guys done it?

thanks

Not a problem. The case gets blown out. Basically a 375 Wby without the radius shoulders.

thanks paul,

how different are the 375 h&h and the 375 weatherby?

could you just get a 375 weatherby reamer instead of a 375 h&h ackley reamer?

quote:

could you just get a 375 weatherby reamer instead of a 375 h&h ackley reamer?

Sure if you wanted a 375 Wby. Due to the 375 Wby having a double radius shoulder it looks a little different. Capacities are basically the same. Both give you around an 8% capacity gain over the 375H&H. I don't care for the radius but there is really nothing wrong with it. Key issue I would check is the throat length. Most Wby have a real long throat to allow bullet jump helping to allow more powder without a pressure spike. Often you will find Wby reamers with both a long and Std throat. With the same throat you wouldn't be able to tell the performance of the two apart. While you can(or at least could) buy 375Wby brass you can make both buy simply fireforming 375H&H ammo.

Do not confuse the 375Wby with the 378Wby. The 378 is much larger.

Or you could 375 JRS it, which is just the 8mm Rem Mag necked up to 375. A 375 JRS reamer will clean up a 375 H&H chamber OK, you can either fireform brass from H&H cases or neck up Rem cases or I think that A squared & maybe Qual Cart have properly headstamped cases.
Steve

I just had a 375 H&H AI made, and I'm very impressed. You can shoot standard 375 H&H (also 375 Weatherby) ammo in it, should you loose or run out of ammo. 375 H&H is widely available in Africa.

The reloading literature indicated that one could get over 2900 fps with 300 gr. bullets with the 375 H&H AI - that literature is correct! I'm getting 2933 fps with 300 gr. bullets using 94 grs. of MRP, and with no pressure signs and tight primer pockets. This is spectacular performance, and with much less powder and blast than the equivalent velocity in the 375 RUM or 378 Weatherby. One can exceed 3000 fps with the latter two, but the pain factor is also exceeded for most shooters.

I've had a JRS and Ackley. Very impressive rounds with worthwhile gains over the H&H. Whether its needed is another story. While I could launch 300s at 2900+, at least in my gun that was too hot. 2800ish was much better. As a side note my favorite 378/270TSX load turns out to only be going 3000 fps. Too bad but it shoots so good I'm not going to mess with it.

Does the .375 Ultra Mag. NON WILD CAT fit into this discussion somewhere? roger

I can,t see how the blown out , improved , H&H case can produce 2900 fps from a 26 " barrel .with a 300 gr bullet..........................
But enough people report it that there must be something to it .......Even Stan Skinner in Guns & Ammo did with the factory 375 Whby in their DGR Weatherby rifle ....It would be worth it to see .... I think the 6 reloads test would be in order unless repiable pressure data can be gotten ....

2700 fps is more like it .. And the next 200 fps are a long way away .......

The 2900+ fps with 300s is real, infact there is published literature indicating 2900+ fps in an 24" barreled 375 AI - using the "old" Norma 205 powder (now replaced by MRP).

My experience with this big bore suggests to me that many big bores are under loaded - that is, many big bore reloads run at PSIs considerably less than 65,000. Why? Shooter fatique and no practical need for more performance.

But the .375-.340 Weatherby looks so much better......

Improving a .375 H&H is like painting an aluminum horse trailer, it serves no earthly purpose!! You cannot improve on perfection.

I'm beginning think that the 375 H&H Ackley Improved is about the perfect big bore. When loaded to its potential, it'll provide massive down range energy as well as a flat trajectory. This is a 600 yd weapon. Importantly, the average hunter can handle the kick and blast, but it's hard to believe one can handle more without significant pain. The 375 H&H doesn't quite provide the trajectory and the 378 Weatherby is just too much of a canon. Any thoughts?

IMHO, improving the 375 H&H is closely analogous to a beautiful, classy woman getting a boob job. It will make her tits bigger, but she won't be as classy. Lou