Ackley Improved Education

[Rick Richard]

Not enough benefit for me. I can't see the additional steps such as fire forming, added cost for loading components and wear on barrel to make it a "Win" for a little extra velocity. And YES, I have been down this road before.

 

[Seabeeken]

I have never had a feeding issue in my bolt rifles with Ackleys. I have had feeding issues with the 284 rebated rim when fired in the same actions. These feeding issues are few though. Ive never used an ai in a semi auto though. As for brass, I am still using the same brass I was using 20 yrs ago and some have 10 firings on them. I do have a few 7x57ai cases showing loosening primer pockets however. I push mine hard and get the same pressure signs as regular cases. A down side is the necks shorten slightly after forming and sometimes need a truing pass with a trimmer to square up the neck IME. With modern powders I see significant improvements in speed, especially in my 250 and 257 ai's.
When I was looking at building a 22-250AI, I eventually opted for the 22XC simply for a better supply of brass and longer neck. JME.

 

[cajun]

Feeding issues with AI's are largely overblown. The 280 AI I have feeds and ejects without issues. The shorter fatter rounds with steep angles can be more of a problem but lots of guys running BR based cases in PRS. I think the latest version the GT is a 35 degree shoulder.

 

[MagnumManiac]

Thanks all for the info. I have asked this question for years and the main answer I got back was that Government and Manufactures won't build AI style Cartridges was due to feeding issues. If it is because of feeding issues then why would a hunter or competition shooter use the AI?
I have built AI cases myself but then I look at the cost associated for some extra FPS. If wanting more velocity why not go to a different cartridge?
Cost for some more FPS:
Custome Reamer
Custom Dies
Work involved in Fire Forming
I think that the Ai 40 shoulder is a good idea, but manufacturesdo not think so much.

I think you are missing the point here. Improved cases are not done for a velocity increase, it is done to improve all aspects of old tapered cases that have been plagued by these body tapers with excessive stretching and difficulty keeping the brass consistent, when it moves this much, it is very difficult to size precisely and it is all over the place.
The 375H&H is a prime example, 3-5 shots and that case has already required trimming after every shot. The Weatherby has no such problem and the brass doesn't stretch and become a PITA to size consistently.
Ammo makers want their OWN designs so they can hype them up and make rifle/ammo sales by introducing NEW stuff. The AI on existing cases isn't enough of an incentive.
My own wildcats have 30°, 35°, 40° & 45° shoulders, the reason is that these angles have proven to slow throat erosion, as calibre increases, the shoulder angle reduces because the bore is getting larger and a steep angle no longer works as efficiently. Throat length also has to change with bore diameter.

Cheers.

 

[ntsqd]

Someone on the first page posted that Ackley commented on the .22-250 AI being the best improvement. I've read almost all of his book and in what I've read his only comment that I recall in this regard was pointed at the .30-30 AI. The charts that I've seen on AI performance vs. the parent chamber show this to be results, that the .30-30 benefits the most from the AI treatment. As it happens a Win 64 in .30-30AI fell into my lap. I've done no load work with it, I've only barely started on forming cases by shooting it. With regard to the comments/concerns about feeding, I have not experienced any trouble with the feeding in that rifle. I was expecting that there might be and it hasn't happened.

When I had a .243 barrel made I went AI. I've posted about why before and it's for the case (& possible throat) saving reasons that have been mentioned in this thread already. That it might speed up the bullets was a secondary consideration.

Someday after I retire I'd like to build a switch barrel rifle in .22-250AI, .243-250AI, and .250 Savage AI. Mostly because.

 

[lancetkenyon]

"Ackley Imp" is a common misnomer for "Imp 40°".
If PO Ackley didn't do the wildcat, it is not technically an "Ackley Imp".

For me, I have/had numerous Imp 40° cartridges.
250AI
25-06AI
.260AI (x2)
6.5-.270AI
6.5PRC/SI
6.5SS (x4)
7SS
.280AI

I have two more in the works. One is waiting on a reamer, one is in reamer design phase.
25PRC/SI
25MBK (secret stuff)

 

[akdad]

"Ackley Imp" is a common misnomer for "Imp 40°".
If PO Ackley didn't do the wildcat, it is not technically an "Ackley Imp".

For me, I have/had numerous Imp 40° cartridges.
250AI
25-06AI
.260AI (x2)
6.5-.270AI
6.5PRC/SI
6.5SS (x4)
7SS
.280AI

I have two more in the works. One is waiting on a reamer, one is in reamer design phase.
25PRC/SI
25MBK (secret stuff)

Lance,
What do you see for brass life typically?

 

[lancetkenyon]

Lance,
What do you see for brass life typically?

Depends on the brass. And how hot you run it. Primer pockets are usually the limiting factor. I anneal every firing.

On my 6.5PRC/SI, I started testing with 20pcs of Lapua 6.5PRC brass. I now have 16 firings on it.
On my .25-06AI, I used Rem R-P. I had 9 firings on it when the barrel went south.
On my .250AI, I used Rem R-P. I had 8-9 firings on it.
On my .280AI, I used Nosler. Had 5 firings on it before I had to replace. Pererson lasts longer. But has less capacity.
On my 6.5SSs, I used Norma at first, now ADG. I had 5x on the Norma when I sold that rifle. I have 5-6x on the ADG now.
On my .260AIs, I use Alpha brass. Inhave up to 5x firings on some of the brass so far.

 

[memtb]

Hello all!

I started this thread about the .22-250 which quickly went to…get that chamber improved!
https://www.longrangehunting.com/threads/custom-22-250.355626/#post-3066278

The above thread interested me in the AI treatment of a cartridge greatly. So I'm doing research. The vid below was insightful.


What is your experience with the AI world? What is your opinion why more cartridges aren't SAMMI approved?

What cartridges have you tried and didn't think the juice was worth the squeeze?

Fire forming tricks/shortcuts?

Dies…how hard to obtain what you need? Redding seems to make many. Other ideas?

Gun smith pluses or minuses with your experience?

Can you do prefits? If so, who?

Is the case life extension a legit?

I'm a very traditional guy when it comes to cartridges. I enjoy getting what I can out of factory rifles. I've been loading for 30 years and I feel it's time to get weird. Thanks in advance!

To AI is not getting "weird"…..it's getting smart! memtb

 

[akdad]

Depends on the brass. And how hot you run it. Primer pockets are usually the limiting factor. I anneal every firing.

On my 6.5PRC/SI, I started testing with 20pcs of Lapua 6.5PRC brass. I now have 16 firings on it.
On my .25-06AI, I used Rem R-P. I had 9 firings on it when the barrel went south.
On my .250AI, I used Rem R-P. I had 8-9 firings on it.
On my .280AI, I used Nosler. Had 5 firings on it before I had to replace. Pererson lasts longer. But has less capacity.
On my 6.5SSs, I used Norma at first, now ADG. I had 5x on the Norma when I sold that rifle. I have 5-6x on the ADG now.
On my .260AIs, I use Alpha brass. Inhave up to 5x firings on some of the brass so far.

Thanks for a really concise reply!!!!
These threads have me thinking I should take my 220 swift barrel that's only got 3 shots thru it and have it done just to save brass since it's so bad at stretching.

 

[memtb]

Lance,
What do you see for brass life typically?

Not Lance and no where near the experience of Lance, but with my only AI (.375 AI) …..I toss the brass after 10 firings. Though, I may not need to…..I had one fail (separation at the web).

Since then I've gone to barely "kissing" the shoulder when resizing….to the point of slight resistance when closing the bolt.

With today's component shortages/prices, I should run a test to see how many firings I can get with my brass and my present procedure!

Hell…..I may even start annealing my brass! memtb

 

[VinceMule]

My experience has been with more varmint cartridges

17 Ackley Hornet-4
22 K Hornet-2
223 AI-8
22/250 AI*-12+
6BR Ackley Improved
6/250 AI-2
243 AI-8+
6 Rem AI-4
25/06 AI-1
260 AI-2
6.5 Rem Mag AI-1
280 AI-4

All varmint cartridges were fire formed while hunting, deer cartridges FF'd with Bullseye and cream of wheat.

The only cartridge I considered a waste of time and funds was the 22 K Hornet.

PO Ackley spoke of the "interference point". If you take a reamer print, draw lines on the Shoulder, now look where they intersect. The Interference Point is a focal point where powder gases converge, which has a huge impact on throat growth.

So, there are two ways to take advantage of the Interference Point, change the shoulder angle to where those lines intersect in the back of the neck and second, make the neck longer. I have played with Making the necks longer on Formed cases, and have verified that PO Ackley's theory is indeed correct. When you make the necks longer, a piloted neck reamer is used in the chamber to make the neck longer, then a unithroater is used to cut the freebore you want to length. The pay off in barrel life is substantial with 35*-40* shoulders with long necks.

For what ever it is worth, I have had many conversations with Dave Kiff about these issues, and it is of his opinion that improving past a 37* shoulder angle is wasted.

As far as feeding issues, I had to modify the Ruger 77 Mark II feed rail for the 17 Ackley Hornet, and the 223 AI does not feed well in the stock 700, but changing to detachable mags fixes that problem. All the other larger cases have had no feeding problems on Rem 700's and Rugers 77s that I and friends have used.

 

[ButterBean]

Thanks for a really concise reply!!!!
These threads have me thinking I should take my 220 swift barrel that's only got 3 shots thru it and have it done just to save brass since it's so bad at stretching.

A 220 Swift AI is Bad Medicine

 

[VinceMule]

I hunted coyotes with a guy that ran a 220 Swift AI, and it is a monster to say the least. If Swift brass was available today, I would have one. I am forced to go 22/243 AI, and the 220 Swift brass is probably stronger brass if you are not running Lapua brass.

The Swift improved is one of the very best AI's, yet few have gone down this road because it was not written about in the gun rags.