Re: 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.