Maybe powder has changed over the years... or maybe Ackley included the data from others without verifying... or maybe testing was done with 32" barrels, but loads and velocities given often seem way too optimistic. Example... 220 grain driven by 75 grains of 4831 (assuming Hodgdon but does it matter?) resulting in a MV of 3066. That would be about max for the 8mm Mag with way more powder.

I think a lot of the #s Ackley used were somewhat of a stretch and could be disputed and or questioned.

I had a pair of his books (Vol 1 & 2), read them cover to cover and gave them away. Years later I found another pair, read those cover to cover, and sold them. His articles and destructive tests were fascinating. Some of his improved cartridges achieved huge gains over the original versions, others not so much.

Ackley included his own load data and results in the manuals. But he often included other's loads and for some cartridges that's all you got. He was very good about telling us when he used data and loads that he had not personally tested. He was from an era when accurate chronographs and pressure testing equipment were only found in labs and not widely available to reloaders. So a lot of his data was estimated by comparison to known loads, guesswork, conjecture, and taking someone else's word for their guesswork. Most of his loads were worked up by looking for "pressure signs" like watching for primer flattening, feeling for sticky bolts, and measuring "excessive" case expansion. Years after he published his handbooks, testing by others revealed many, perhaps most, of his max loads were ridiculously over-pressure.

Ackley's load data is very useful as a starting point. You should always start off well, well below his top loads,. Even so, attempting to equal them is unwise.

I have all of his books; do not use any of his loads. I think that many of them were interpolations or guesses.
Ok, I see that grenadier just said that. Anyway, use his load data as reference only. Not facts.

Much of his stuff works fine, some does not, Isee the same experience on the internet, suspect it has a lot to do iwth the gun used in tests...I don't think PO had a chrongraph, just a speedometer!!

I never seen one in his shop.
at least I didn't recognize one I should say, but then again I was young enough I wouldn't have really known what to look for.
so maybe he did have one [shrug]

I was in his shop a lot [2-3 days a week] when I was a teenager.
mostly just talking to him in his office, or on the back steps, and he did rebarrel a Mexican Mauser for me.

Parker was an ok engineer, but a great self-promoter. Much if his testing (destruction, headspace, etc.) is not particularly useful because he had no idea of the pressures his loads attained (nor could he know), but it is often misleading. Even his “improved” case design was over-sold, since even with the infamous enhanced case/chamber grip the maximum pressure could still be transferred directly to the bolt face - meaning there was little to no advantage to the AI designs other than a (usually) minimal case capacity increase.

Jack O'Connor once asked him where he obtained his load data. Ackley’s reply was “from various sources”. Much of it was from experimenters trying to impress him with their self-named wonder cartridge, and redlining the pressures was de rigueur back then. Wait - it still is today in some circles!

Ackley rebored two rifles for me in the 70s and his work was excellent. I still own and shoot them today and won’t part with them. But neither will I believe much of the testing/loading material in his books (mine are the 1962/6th printing edition).



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As I remember his writings, the 30-06 AI showed the least improvement over any cartridge AI'ed.
A "disappointment in his words.

I have both the 7X57 + 257 Roberts AI's.

All his X57 Mausers and the 250 Savage got me about 300 FPS and thats substantial and he stated they proved to be the best of his improved calibers and they are that...

Ray, I agree. When I read his books + found that his best performance was achieved with the 7MM + 257 then I went in that direction. Hell, why reinvent the wheel?

quote:

All his X57 Mausers and the 250 Savage got me about 300 FPS and thats substantial and he stated they proved to be the best of his improved calibers and they are that...

Remember that factory pressures for those cartridges were very low: ~37,000 cup and 45,000 cup respectively. Simply raising those pressure to a modern 52,000 cup would give a major velocity increase. Of course he didn’t pressure test his loads, and it was de rigeur back then to load wildcats well above safe pressures. Current Nosler data shows only minor velocity differences between standard and AI versions of the 8x57 when both are loaded to modern pressures. Ackley knew very well how to spin his products.

While the x57 cartridges had a minor increase in capacity (~6% meaning at most a 3% velocity increase from capacity alone) the .250 had a much greater increase, making it (along with the .22-250 AI) the only original AI cartridge which gave a meaningful velocity increase. Regardless, the AI cartridges are an interesting part of history and they influenced cartridge development for many years.



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quote:

Originally posted by Lamar:
I never seen one in his shop.
at least I didn't recognize one I should say, but then again I was young enough I wouldn't have really known what to look for.
so maybe he did have one [shrug]

I was in his shop a lot [2-3 days a week] when I was a teenager.
mostly just talking to him in his office, or on the back steps, and he did rebarrel a Mexican Mauser for me.

Some say that he blew up a lot of guns. Is there any truth in that?


Also how much resemblence do the powders that he used bear to the same numbers that are available today? Is his H4831 similar to the H4830 available now?

He was right on in his assessment of the 6.5-06AI vs the 6.5-06 noting that maximum/optimum efficiency was achieved with the 6.5-06.

Parker is one of my heros... his loads ARE optimistic .. in terms of pressure and vels

A standard 250-3000 can attain easily 3000 fps with a 100 grain bullet if loaded to the pressures used by shooters of the Ackley version. The 250 Ackley has about the same capacity as the standard 257 Roberts so it will achieve about the same velocity at the same pressure. Any of the big gains by Ackley cartridges are the result of higher pressure loadings.
The 30/30 AI or the 30/40 AI, increase case capacity by a noticeable amount but even these, at the same pressures, don't actually gain that much. A 30/40 AI, in a strong action, can generate some impressive velocity but so can the standard 30/40. Regards, Bill

Over the years I was very interested in a lot of the Ackley designs. I still have reamers and dies for 22-250 Imp, 257 Imp, 30-30 Imp, 280 Imp, and 30-06 Imp. The 280 Imp is a good performing round for the 30-06 length actions. Kenny Jarret promoted his "Bean Field " rifles in that chambering a lot.

The one I used more than any other was the 257 Imp. Good velocity gain with sane loads. Always excellent accuracy. I believe the reason I got good velocity gains on all of the Ackley designs was I always throated the barrel to fit the intended bullet with the base of the bullet seated at the shoulder neck junction. This always added just a tad more powder capacity.

I have a friend who builds a lot of long range rifles for hunting hogs across wheat fields. He has a private range out to 1400 yards and does a lot of testing. He tells me about tremendous gains with the 223 Ackley Imp.

Ackley was no differnt than any wildcatter Ive ever known, but to give credit where credit is due, I have to say Ackley and all those wildcatters of yesteryear had more on the ball than todays wildcatters reinventing the wheel..Yes the 7 and 8 mm were and still are underloaded but I can get a few hundred fps out of my 250-3000 ackleys over most max handloads, pressure? that can be there with or without improving a case, causation? too much powder..