Having lost both my father's reloading notes and the P.O. Ackley books, I'm in need of a couple pieces of information.

Did a chamber cast on the rifle, which as actually made by P.O. himself. Best I can tell, OAL is 2.545 - 2.550". Anybody have any better measurements than that for the cartridge?

Starting loads? I have a manual showing loads for the 358 Norma, but the Ackley appears to have a bit more case capacity, so I'd like to not go too low and risk a pressure wave. Maybe 60 grains of IMR 4064?

Appreciate the help!

A 358 Norma is 2.52" Loaded to the same lenght I can't believe there would be much difference. I would suggest you simply weight the water capacity and then compare it to the 358Norma. Adjust for % difference in case capacity and start at the bottom of the 358N loads and work up.

Not sure what bullet yu are talking but 60gr of 4064 in a 358N is down in the 40-45,000 range.

Good advice on taking the proportionate case capacity and adjusting the starting load accordingly. The Ackley case has the shoulder a bit further forward and will have more case capacity, but it won't be so much that it would invalidate adjusting the starting load as you suggest. I'll try it.

By the way, I should have mentioned it's a 200 grain bullet. In this case, Barnes Triple Shock.

quote:

but it won't be so much that it would invalidate adjusting the starting load as you suggest. I'll try it.

Before the various loading programs I used this method to start loading all my wildcats.

Give me the capacity and loaded OAL and I'd be happy to run QL for you.

quote:

Originally posted by H T:
Having lost both my father's reloading notes and the P.O. Ackley books, I'm in need of a couple pieces of information.

Did a chamber cast on the rifle, which as actually made by P.O. himself. Best I can tell, OAL is 2.545 - 2.550". Anybody have any better measurements than that for the cartridge?

Starting loads? I have a manual showing loads for the 358 Norma, but the Ackley appears to have a bit more case capacity, so I'd like to not go too low and risk a pressure wave. Maybe 60 grains of IMR 4064?

Appreciate the help!

Ackley made afew calibers off a shorten 375 H&H or 300H&H case like the 35 AI mag case length 2.53" and he has reloading data for it in vol 1 in his book.

60 to 65gr/IMR-3031 200gr bullet
74gr/IMR-4895 200gr bullet

62 to 65gr/IMR-4350 250gr bullet
68gr/IMR-4320 250gr bullet
70gr/IMR-4895 250gr bullet

70gr/IMR-4895 275gr bullet

68gr/IMR-4895 300gr bullet
74gr/IMR-4350 300gr bullet

I would start around 10% below those single loads that I listed and case capacity was over 75gr of powder in the article.

Well good luck

2.53" is a great piece of information to have. Havng lost my copies of his Volumes I and II in a move, this information, plus the loads he listed, is very helpful. Much appreciate it!

Thanks to the AR folks for helping me with this project. I slogged through the process of taking 375 brass, squeezing it down in a forming die, trimmed to length of 2.53". Also tried some out of the box 358 Norma brass to see how short the resulting neck would be.

Got a surprise !

Shot it today, fire forming cases from both 375 H&H and 358 Norma. The 375 cases actually went down in length by .010", while the Norma cases lengthened by .013". Suspect this is because the taper on H&H cases meant the case body and shoulder had more room to expand to fit the chamber. Had so much room, the overall length ended up coming down instead of lengthening. Meanwhile the Norma cases moved the shoulder and neck forward just a bit.

Didn't anticipate that, but it makes perfect sense.

Oh and if anyone is interested, I used 59 grains of IMR 4064. A full strength load, just on the lighter end of the min to max loading range.

Conclusion - just use the Norma cases since they end up pretty close to the official case length (just .009" short), and are a heck of a lot less work. Duh !!