Ackley Improved Education

[woodnut]

P.O. Ackley was a very smart guy! I believe he realized the straighter case with the 40' shoulder was a better design to give about 100fps increase in velocity, less bolt thrust, and longer case life. You could also fire factory ammo in an A.I. chamber, which is how you fireform them anyway. I wonder if Hornady guys thought about Ackley when they came out with the Creedmoor rounds as they are very close to his thinking.
I have several A.I. rounds, but one is very interesting. P.O. did NOT like the 223 so he never made a 223A.I., but I have one. This round gives me a 300 fps increase to 3600fps with a 55gr. bullet! Yes, that's right. It is a very, very accurate AR15 and a Cooper rifle.

 

[FireFlyFishing]

I have several A.I. rounds, but one is very interesting. P.O. did NOT like the 223 so he never made a 223A.I., but I have one. This round gives me a 300 fps increase to 3600fps with a 55gr. bullet! Yes, that's right. It is a very, very accurate AR15 and a Cooper rifle.

Interesting. What length barrel are you using and how well does that feed in an AR platform?

 

[FEENIX]

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!

I responded to your original thread, and no, it is not my fault for convincing you to go AI.

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

For a true AI, as Ackley intended, the only one is the .270 AI, which is also not SAAMI. IIRC, he did not explore the .270 Win (perhaps someone can shed some light). However, I have a few wildcats - .30 Gibbs, .30 LARA, and .338 Thor, thus far. I was thinking of doing something in ICL, but my .338 Thor already have ICL's shoulder angle. "I" do not pay attention to whether they are in the SAAMI.

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

I was pleased with all of mine. Only you can measure the value added to your investment/time and efforts.

Fire forming tricks/shortcuts?

For a true AI like what you are trying to accomplish, load and shoot. Ackley designed his wildcats to fire the parent cartridge.

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

For common AIs, they are fairly easy to find. It depends on whether the manufacturers keep them on the shelves or if they need to be specially ordered.

Gun smith pluses or minuses with your experience?

I have been working with my go-to GS since 2003 and am very pleased with my experience.

Can you do prefits? If so, who?

Depending on your action, yes. Most barrel manufacturers do pre-fits, but you must check their offerings. In our neck of the woods, https://www.x-caliber.net/bolt-action-barrels, and https://mcgowenbarrel.com/shop/full-custom-barrel/, and yes, I have used them and am very pleased with their performance.

Is the case life extension a legit?

Improved or not, if you run them hot, brass life will suffer.

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!

Enjoy your new endeavor and don't sweat it.

 

[FireFlyFishing]

I did a 30-284ai, mostly for slight powder capacity increase and reduced trimming. The jury is out on if it would be better than a straight 30-284 because my first chamber cut with the reamer was sloppy. That's my one experience with an AI chamber aside from researching it heavily.

I recall you have a thread on that project. That would be disappointing the first time around for sure. Did you come to a conclusion on what could have been better for you from the start on that project?

 

[woodnut]

Both are 26 inch barrels and it's a 14 twist.

 

[FireFlyFishing]

I responded to your original thread, and no, it is not my fault for convincing you to go AI.

Hah! There were many conspirators on that thread that got me thinking…

 

[FireFlyFishing]

Both are 26 inch barrels and it's a 14 twist.

I figured they'd have to be longish to accomplish those velocities.

 

[Buttermilk]

AI cases have some drawbacks from making brass. More case loss when form new brass from a manufacturing standpoint. That's one reason the 30° shoulder is more prevalent than sharper angles.

I've had some Ackley Improved cases and really like them. My three favorites were 30-280 AI, 280 AI and 30-30 AI.

Less case trimming is one benefit, though I found I still needed to trim, just not as often.

As time as went on, I've come to prefer the 35° shoulder angle mostly. However, 30°, 35°, and 40° all suit me quite well.

A 22 Creedmoor is essentially a modernized 22-250 AI.

 

[KsKevin]

Anytime a case has been designed with much less case taper, forgetting what shoulder angle is used, is simply an Ackley concept adopted and used, SAAMI accepts that and implements those dimensions. Winchester were fundamental in reducing case taper on many of their 1950's case designs. I'm sure these were inspired by P. O. Ackley's designs.

Cheers.

To this point, Look at all the PRC and creedmore chamberings….they all have little body taper although they went with 30* shoulders vs 40*. Several other chamberings with minimal body taper and 35* shoulders.

I have a 280AI and can attest to not having to trim brass. I trim when cases are new to get all to exact same length. Some now have 6-7 firings and haven't been trimmed since new and have only grown 0.010" (did so after first 2-3 firings and effectively haven't changed since).

 

[Coyote Shadow Tracker]

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.

 

[Plinker147]

For every AI cartridge one can go find a factory option that duplicates or has increased velocity. I think that's a big reason they didn't get standardized. I have 280 AI and really like it for heavies bullets. But 40 degrees has a few issues with donuts and easy to crush a case. I haven't experienced the trim less in mine. I think modern day cartridges have proved the 30 degree is the sweet spot.

 

[Barehandlineman11]

I single feed all my bug guns anyway and never had a magazine issue feeding other then case to long too mag feed. But it can be a hassle in wrong set up.

 

[KsKevin]

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've not tested this so this isn't fact but just more if a hypothesis than anything but I would suspect the feeding issues on a 40* shoulder would be more pronounced when the delta in case diameter vs neck diameter are large (ie making it a bigger 'wall' at the case shoulder to 'climb' when feeding). My experience with the 280ai has been trouble free and smooth feeding but I could see something like a 22-250ai being more of a challenge. Would be interested in hearing any insights from those who've messed with several AI cartridges

 

[ButterBean]

What calibers have you done @ButterBean?

22-250AI, 243AI, 22-243AI, 22-06AI, 25-06AI, 270AI,