Which Ackley Improved Improves the Most??

Mr. Ackley was a trained engineer. Syracuse Univ??? Read his books and he makes the point that he "improved" cartridges to reduce the back thrust on the action and to keep the burning powder in the case extending barrel life and sharpened the shoulder to slow case lengthening. The extra velocity was "gravey on the taters."

He writes of firing a 94 Winchester, .30/30 Improved, without the bolt locking lug in the gun. [NOT from the shoulder!] The improved case gripped the chamber sufficiently that the bolt stayed in the gun.

Obviously taking a funnel shaped case like the .22/250 and straightening out the sides to reduce back thrust also greatly increases powder capacity. More powder, more velocity and more cost. More funnel eliminated, more performance. He wrote the .30/40 Krag Imp, NOT IN Krag rifles (one locking lug and OLD) would equal the .300 H&H factory ammo. (.300 H&H was not loaded hot for use in places that are hot, Africa, India, etc.) .38/55? Nothing to improve.

So if you hunt a couple times a year for meat in the Rockies. Get up close. 50 yards or less. Shoot the young and dumb good eating, tender animals... factory .30/30 is o.k. As the distance gets greater, improving the same gun to .30/30 Imp and reaching the performance of approx. the .300 Savage makes the work a bit easier. At the same time you need custom dies... you burn more powder... Will you use the gun enough to make it a good investment or is this a toy without regard to costs?

When I was young and dumb, I asked by letter about improving the .308. Most graciously he pointed out to me that there wasn't much to gain. Body was almost straight already. Compare the .308 to the .300 Savage improved and what do you see. Longer neck on the .308.

.257 Improved treads on the heals of the .25/'06 with lighter bullets. Heavy bullets and more powder helps. Of course, the Bob (.257) was standardized at 45K CUP, thus the later +P loads.

So what do you want/need? You want top velocity (the .300 Ackley Magnum was out long before Mr. Weatherby began his "marketing" work) ??? You want longest case life? Or will any factory gun get the job done once a year when you go out with the boys? (and girls???) [Or are you the one who stays behind with the girls...???] The books are a treasure. Keep looking. eabco.com lists them. Third volume reportedly in the works but that has been forever. ?? Great foundation for anyone with this kind of interests. Mike Bellm, bellmtcs.com bought out Mr. Ackely. No idea if he has any books around. You could ask. Luck with your learning.

Mr. Ackley was a trained engineer. Syracuse Univ??? Read his books and he makes the point that he "improved" cartridges to reduce the back thrust on the action and to keep the burning powder in the case extending barrel life and sharpened the shoulder to slow case lengthening.

Click to expand...

Actually, P.O. sold us all a bill of goods with all his claims of 'reduced back thrust' - his mechanical engineering degree suggests he knew the truth . The thinking man already knows this too. Back thrust is controlled by the strength of the brass, not the case shape. Remember the incipient head separations so common on some magnum brass and the likes of the .35 Remington? That happens because the front portion of the case expands to grip the chamber walls, while the un-expanded thicker part of the case is slammed back against the breech, stretching the case if there is room or just transferring thrust if there is not. Most cartridges already do what Ackley claimed only his did. The .30-30 trick described in the above post has no science behind it and it is easy to demonstrate that it does not show more than slight-of-hand.

Note that I respected Parker a lot while he was alive, he built several rifles for me in the 1970s and we corresponded some. But he was in business to make a living and this 'back thrust' thing was just marketing. To me the real benefit of his 'so-called improved cartridges' (his term) was the increase in case capacity and thus the increased velocity. He still stands as one of the all-time leaders in firearms technology and design.

A fine explanation of Ackley's Mistake along with tests debunking his claims can be found in the November 2004 issue of Precision Shooting magazine.



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The .257AI is a wonderful cartridge (I sold mine in a fit of idiocy years ago) but it is not the equivalent of the .25-06. I believe this is important for new reloaders to realize - there is no magic in cartridge design, and the cartridge with the greater powder capacity will give higher velocities at the same pressures. It will also use more powder, but that difference is certainly not linear, as the pressure-tested data below shows. Anyone can overload a .257AI cartridge to increase its performance, but then the same can be done to the .25-06...

Using the Sierra Manual referenced above:
.257AI - [email protected] fps - 44 gr
.25-06 - [email protected] fps - 53 gr....6% faster with 20% more powder

.257AI - [email protected] fps - 44gr
.25-06 - [email protected] fps - 49 gr...7% faster with 11% more powder

Using the Nosler #5 Manual:
.257AI - [email protected] fps - 44 gr
.25-06 - [email protected] fps - 57 gr....4% faster with 30% more powder

.257AI - [email protected] fps - 51 gr
.25-06 - [email protected] fps - 52 gr...4% faster with 2% more powder

It is interesting to note that their own data puts the lie to what is written in the text for their .257AI data. Sierra states:
"In fact, this version is far more efficient than the .25-06, producing essentially the same performance while using substantially less powder"
Most shooters would not consider a shortfall of 200 fps to be "essentially the same performance". That would mean there is no difference between the .257 and the AI versions. And is 11% "substantially less powder"? Too often, what is written in the text of loading manuals bears little resemblance to what the loading data shows. :

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Yes, it goes back to what we should already know. Pick the performance level with ALL the factors considered, in other words velocity, barrel life, trajectory, wind drift, etc. What overall performance do WE want? Efficiency has relevance, to some more than others & to me it has relevance, but it falls well behind the other factors previously stated. It is a fact that the 25-35 or 250 Sav.
is alot more efficient than the 25-06 or 25-06AI, but it is not relevant to me, as the performance does not match my personal goals.
So we strike a balance of what we want & that is what matters, none of us should give a rip about what others think of our choices.
Sometimes the AI rounds give me something I want & I use them, sometimes they don't & I use something else, just the way it is. If we draw false conclusions about the performance of a given round, then did not research the round logically. And some folks will do that well after this thread goes away.

Minnesota1 said:

I haven't been able to locate a reasonably priced P.O. Ackley book(s). I know some of the Impoved cartridges don't give much extra bang for the buck. Would you rate the best Improved cartridges that give the best improvement over their standard counterpart? Are the best the 22-250, 30-30, 257 roberts, 223? If you can rank them accordingly, as many as you want to, I would appreciate it or if you have a comment or commentary on the cartridges or their effectiveness, etc. I would like that as well.

Thanks,

Bob

Click to expand...

A few have already been mentioned like the 30-30, 30-40, AND .250 Sav.. Rounds such as these and rounds in general, that first in the commercial state are relatively low or modest pressure rounds. That and those like these with a fair bit of taper in which to increase capacity. Those are cases AI'd will give the most return. Then it's pretty much up to the particular firearm likes and dislikes, as to what actual gain in performance may be achieved.
The .22-250 has lots of taper, but is a fair high intensity round since it was stanardized. You will see capacity increase, but on the lower end of velocity gain when you look at AI comparisions. The others as in like .257Rob. and those based on the 57mm case, in general were loaded to modest pressures and have modest gains in capacity, but still warrent AI'ing in my mind.

Dave