Ackley Improved

jdemora

jdemora

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What all is entailed in a Ackley Improved gun? DOes it still eat regular ammo or what ? I am not sure exatcly what is involved and how it alters the cal and performance and what type of ammo they use.........
thanks I seem to see this more and more often lately......
 
Find a gunsmith with the reamer and get him to do the chamber. No other changes should be required to the rifle.

A proper AI chamber will aloww you to shoot factory ammo in it resulting in the improved size empty brass. Headspacing is the same from factory to improved.

.223AI is a very good conversion. :)

223AI-2.jpg



sc
 
AI straightens up the case with less taper and has a sharper shoulder.

It allows more case capacity, with is usually fairly efficient and because of the shoulder change the brass will not flow forward as fast.

Results in more velocity, and longer brass life.

6mm_6mmAI-1.jpg





sc
 
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One downside is that the dies are custom order and can be a bit expensive depending on the caliber.

Some of the more common calibers are more available such as 257Roberts Imp and .223AI.

Check out RCBS and CH for the custom calibers selection.


sc
 
I have done a few .22-250 AIs. Raises performance to Swift level. A properly done AI conversion allows safe use of factory ammunition. It is necessary to set a factory barrel back, to allow headspace to be set properly. If the chamber is just reamed without setback, there will likely be excess headspace for a factory round.
Some cartridges are significantly "improved" with an Ackley conversion, with others, it is not worth the effort.
 
I have or have had over the past 40 years, the 223, 250-3000, 7X57, 280, 30-30, 30-06 and 8mm-06 all done up in the Ackley configuration.

One of the best is the 250-3000 Ackley Imp. It raises velocities more than 200 fps. I have owned three of them over the years, and they would all get 100 gr bullets to 3300 fps! All three were exceptionally accurate, and have all gone to friends of mine who wanted them. Doug on the board here got my last one, built on a SAKO.

I really "need" to build another one. :cool:

Ted
 
If you are thinking of AI'ing a 260 remington, you would be better off having it rechambered to 6.5-284 winchester. Brass is available, you would likely gain anything over the 6.5-284.
 
Why not? said:
I have or have had over the past 40 years, the 223, 250-3000, 7X57, 280, 30-30, 30-06 and 8mm-06 all done up in the Ackley configuration.

One of the best is the 250-3000 Ackley Imp. It raises velocities more than 200 fps. I have owned three of them over the years, and they would all get 100 gr bullets to 3300 fps! All three were exceptionally accurate, and have all gone to friends of mine who wanted them. Doug on the board here got my last one, built on a SAKO.

I really "need" to build another one. :cool:

Ted
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Hey Ted, don't forget the 25/06 AI you dealt to me as well ;) :D


martinbns said:
If you are thinking of AI'ing a 260 remington, you would be better off having it rechambered to 6.5-284 winchester. Brass is available, you would likely gain anything over the 6.5-284.
Click to expand...

A great cartidge for sure, but if you're like me and like thinks that are different the 260 AI sounds like a lot of fun. It's something that I've considered in the past, but I'm now going to have a 6.5 WSM built instead.:D
 
Can someone give me info on the 22/250 AI. I'm thinking of having my Savage 12FVSS done but I have no idea what improvement it will make in terms of f.p.s and barrel life. Also, how much extra case sapacity does it give and how does that affect the powder used. I'm currently using H380 under a 55 Vmax for 3793 f.p.s. Like most Savages'this one is a tack driver.:D :D :D
 
I just had a 6.5x55 AI built, and it makes a neat looking package!! The Chamber is cut so a factory round gives just a bit of resistance in closing the bolt. When the factory fodder is fired, you end up with a perfectly fomed AI case for reloading. Body taper is reduced from about .040" down to around .010" and the 40º Shoulder looks a lot more abrupt than the original 25º one. I have not compared case capacities yet, but imagine it amounts to 5-8 grains of additional powder in the improved case. Regards, Eagleye.
 
While not mentioned I wondered if the .270 Win is a good candidate for AI. 30 years ago a buddy came up with a custom 270AI that smoked at both ends and blew primers. He claimed that his loads were within limits. Built on a P14 action it was a fine looking rifle but obviously all was not well. Headspace probably. My recourse was to set up two benches away.
Cheers
Ross
 
I have a Savage model 112V that is chambered in 22-250 AI. The Tech support fellows at Sierra said to use 220 Swift loading data. I haven't fireformed any cases yet.
 
While not mentioned I wondered if the .270 Win is a good candidate for AI. 30 years ago a buddy came up with a custom 270AI that smoked at both ends and blew primers. He claimed that his loads were within limits. Built on a P14 action it was a fine looking rifle but obviously all was not well. Headspace probably. My recourse was to set up two benches away.
Cheers
Ross
 
The older the case design, the more case capacity improving it will provide. Older designs have a lot of body taper. One of the best ones are the 30-30 and 303Brit.

Most AI conversions will give 100 to 200fps increase for all bullet weights. How much more powder really depends on the orig cartridge and type of load/bullet used. In general, the max load becomes the starting load but prudence suggests you use a mid load from the orig cartridge as a starting load.

Modern designs like the 260 do not benefit much from the AI treatment simply because their case dimensions are close to being AI anyways. With these cases, you might not gain more then a few fps at the same accuracy. Alot depends on the barrel and the pressure levels/tuning it likes best.

The most notable ones are the short magnums. They are improved as is.

Now there is a second step that you can do which is to move the shoulder forward as well as reducing body taper and sharpening the shoulder. This chamber can increase capacity significantly but factory ammo cannot be safely fired in this chamber.

This is the approach I took when designing my wildcats the 6.5 and 7 Mystic. Both perform like a larger case and do so very accurately. Pics below.

If you decide to do a reg. AI, you do not need custom dies if you neck size. The reg. Lee collet die, bushing die, or standard neck sizing die will work with the AI case and the reg. seater will seat the bullets just fine. In fact with a closer fit to the die, the seater might just work better.

With a shoulder forward wildcat, the Lee collet die can still be used. You just need to put a shim between the shellholder and the base of the die. That is how I size my 6.5 Mystic. Bushing dies will still work as will reg. seating dies.

You just can't FL size. I usually don't bother as the brass is usually worn by the time it grows too much. Properly cut, tight headspaced AI chambers tend to help brass survive many firings.

Another great family of shoulder forward improved 'cats are the Gibbs. Very modern in appearance and performance is as good as they look.

Jerry



The 6.5 Mystic. As far as I can research, a unique wildcat.



Fireforming steps of making 7 Mystic and similar shoulder forward wildcats.
 
jdemora said:
very interesting, can you improve any chambering? even a fairly newer cartridge like the .260?
thanks by the way SC
Click to expand...

Terry's Tactical Two-Sixty AI
"Shooting a mag-fed .260 AI (or .308 prior to 2004), Terry has "beat all comers" in major tactical matches. His wins include the 2002, 2003, and 2005 SniperQuest, the 2004 and 2005 Sniper's Hide Cup, and the 2004 McMillan Sniper Competition..."
http://www.6mmbr.com/gunweek046.html
 
Damadama, the advice about using Swift loads in a 22-250 AI is right on. Read P.O. Ackley's book! He suggests just that and he invented the thing.:rolleyes:
BTW a blown out 270 is NOT a 270AI.:eek: AI stands for Ackley Improved, meaning that it was designed by old P.O.:D
 
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