ackley improved
- Thread starter swarovski
- Start date
What a strange post! Acklyizing calibres has many other benefits such as improved case life and accuracy. Most people shooting these calibres, such as myself enjoy using something a litle different or a "wild cat"admitidly some ofthe benefits may seem small, however they are benefits and also the joy of using something a little more bespoke makes it even sweeter! In the right hands any legal calibre will consistently do whats required so whats all the fuss about? Life would be weird if we all drove the same cars, or maybe we should still be dragging our knuckles along instead of evolution/make small improvements etc?
Brithunter
Well-Known Member
The improvement will depend on which cartridge is being improved
Ackley only did some due to customer request and hated the results. I believe the 270 Win AI as one of those he didn't like. Now ones like the 30-30 Win AI give a lot of improved performance as does the 257 Roberts AI.The Improved route is not for everyone
personally I own two. A 303 Imp and the 280 Rem AI both for different reasons which suit me but might not suit some one else.
a 257 roberts ai is a 25-06 wannabe surely
The 257 Improved does what a 25-06 can do but with about 10% less powder
Ian.
I'm not sure, but after having read about them for many years, I have just bought one. Hopefully over the next couple of years I will have a clearer idea, but then again, maybe not.
http://www.accurateshooter.com/cartridge-guides/243win/
Regards JCS
The point is the same as making a 243/260/7-08 out of a 308 or a 25-06/270 out of a 30-06. I've had an ackley or two and have always found them an improvement on the parent case. If you dont see the point dont get one, simple.
The biggest overlooked benefit of improved cartridges is the lower operating pressures when duplicating top end parent case loads.
Ian.
Ian.
6mm ai remington really looks superb with the varminting 75 and 87 vmax
Claret_Dabbler
Well-Known Member
A 22/250 AI with an 8" twist is next on my list. Rifle will be going to the 'smith in the next month or two.
jay 22
Well-Known Member
that will be mustard. alan the guy who i was trying to sell the 22/250 fast twist for. is getting a 6x47 barrel on it now i think.
shame really as that fast twist 22/250 was stunningly accurate
Claret_Dabbler
Well-Known Member
Jay, this rebarrel would have been done months ago, except the damn 14 twist factory barrel on this Sako is doing half inch at 200 yards with 52gr A-Max....
I am nearly frightened to ship it.
I am nearly frightened to ship it.
I'm not sure that's true.~Muir
Muir.
I am curious as to why you say that. Could you expand on it a little please? Surely an Ackley case with its increased capacity can propel the same projectile to the same velocity as the parent case but with less pressure?
I realise not all Ackleys are the same but in general terms.
Do you think Ackley users get most of the velocity gains by handloading over and above parent case pressures?
I have 2 Ackleys, a 25-06AI and a 30-06AI.
Yorkie.
I don't think it is worth the cost of getting a rifle rechambered to an AI case (with a few exceptions - 257 Bob being the best known exception), but if you are rebarreling and already reloading there is not necessarily any reason not to go AI. You will not see any significant effect on accuracy, but some cases do benefit from decreased stretch - the 243 AI being one of the better known examples.Your fireforming loads can still be effective hunting loads - for example a lot of folks use fairly useful varmint loads for fireforming 223 AI brass.
The rule is that for any increase in case capacity, the increase in muzzle velocity will typically be 25% of the increase capacity. Most cases yeild increases in capacity of 4 to 8%, and so you get a 1 to 2% increase in muzzle velocity. Obviously a lot of folks achieve greater increases, but they are achieving their gains by running at higher pressures rather than greater capacity. In reality, much of the success of AI cases is actually due to parent cartridges being loaded to lower pressures - and that extends even to some of the more modern cases such as 223 (which is SAAMI 56000PSI) and 243 (60000PSI - when testing the 243 case they found pressures varied a lot as it is a little overbore and hence to reduce pressures a little vs other 308-based cartridges to be confident factory ammunition on average would remain under the safe limits. The 7mm Rem mag is similar).
You also need to consider your feed system - AIed cases are much better feed from single-column midline feed magazines, and may cause problems in a more traditional mauser-type action with a staggered column. And generally, more reliable feed is actually of greater practical advantage than 50-100fps in a hunting rifle. Remember, even the big-daddy of long range bolt-action cartridges, the 338LM, still has a fair bit of taper to it - and the military guys know what they are doing. Reliablity matters.
Is it worth while? Well only you can answer that, but i do find it very amusing that many folks would tell you that the 30-06 is a very much better all-around hunting round than the 308, but laugh at the suggestion of taking a 30-06 up to a AI case. However, there is in fact a greater difference between the 30-06 and the 30-06 AI than there is between the 308 and 30-06! And the 30-06 requires an extra half a pound in the action - yet somehow that is worthwhile and AI is stupid. Also consider the difference between a 308 and 30-06 is effectively about 25 yards ie: a 30-06 is doing at 325 yards what a 308 is doing at 300 yards. ie: bugger all!
The rule is that for any increase in case capacity, the increase in muzzle velocity will typically be 25% of the increase capacity. Most cases yeild increases in capacity of 4 to 8%, and so you get a 1 to 2% increase in muzzle velocity. Obviously a lot of folks achieve greater increases, but they are achieving their gains by running at higher pressures rather than greater capacity. In reality, much of the success of AI cases is actually due to parent cartridges being loaded to lower pressures - and that extends even to some of the more modern cases such as 223 (which is SAAMI 56000PSI) and 243 (60000PSI - when testing the 243 case they found pressures varied a lot as it is a little overbore and hence to reduce pressures a little vs other 308-based cartridges to be confident factory ammunition on average would remain under the safe limits. The 7mm Rem mag is similar).
You also need to consider your feed system - AIed cases are much better feed from single-column midline feed magazines, and may cause problems in a more traditional mauser-type action with a staggered column. And generally, more reliable feed is actually of greater practical advantage than 50-100fps in a hunting rifle. Remember, even the big-daddy of long range bolt-action cartridges, the 338LM, still has a fair bit of taper to it - and the military guys know what they are doing. Reliablity matters.
Is it worth while? Well only you can answer that, but i do find it very amusing that many folks would tell you that the 30-06 is a very much better all-around hunting round than the 308, but laugh at the suggestion of taking a 30-06 up to a AI case. However, there is in fact a greater difference between the 30-06 and the 30-06 AI than there is between the 308 and 30-06! And the 30-06 requires an extra half a pound in the action - yet somehow that is worthwhile and AI is stupid. Also consider the difference between a 308 and 30-06 is effectively about 25 yards ie: a 30-06 is doing at 325 yards what a 308 is doing at 300 yards. ie: bugger all!
Last edited:
Brithunter
Well-Known Member
I think a lot of people get confused with Improved cases. One of the benefits of an improved case is less back thrust on the breech locking mechanism. Due to this a lot of folks think the pressures are lower when in fact they are not unless one is loading the same powder charge in the improved case as they did in the standard non improved case.
Loaded correctly in a strong action like the P-14 the .303 Epps of the Improved like mine which has a shorter neck than the Epss so a bit more powder capacity this 303 improved can about equal the velocities of the 30-06 however it's no longer loaded to standard 303 pressures hence the need to use the P-14 action.
Loaded correctly in a strong action like the P-14 the .303 Epps of the Improved like mine which has a shorter neck than the Epss so a bit more powder capacity this 303 improved can about equal the velocities of the 30-06 however it's no longer loaded to standard 303 pressures hence the need to use the P-14 action
.From memory, the increase in capacity with the 30-06 case is about 3-4grains, or about 7%. If you go to the .30-280 improved, you get nearly double that. Works out at about 100 fps - which is about the same as the difference between 308 and 30-06. My Nosler data shows a little above 100fps between the 30-06 and AI, and a bit less than 100fps between the 308 and 30-06 on average for the same pressure. The 30-06 case seems to be one of those cases that shows a little more improvement than most, which i think is due to the longer case design benefiting from more uniform pressures with the straighter walls. The 243 AI and 257 Bob imp seem similar - you get a slightly more uniform distribution of pressures with the improved case, which allows you to move to slightly higher pressures before you start noticing more cases with pressure signs. We are talking absolutely minutiae though.
Similar threads
