Another Ackley Improved thread

I.O.N.Doyle

I.O.N.Doyle

New member
Been researching some of the threads on the Ackley Improved chamberings and may be finally willing to take the leap but a couple of questions first. If I have read correctly any chamber can be made into an AI but some are better than others? From what I have read most agree that the .243 offering is not a significant improvement. Are there rounds that are more inherent to improvement with this modification? I have three rifles that I would be willing to try this with and a new barrel is not out of the question. I have a .223, a .25-06, and a 7X57mm.
 
I did the conversion to my .257 Roberts (40 degree shoulder angle). It shoots well but I have never put it on the chrono.

Point of impact when fire forming vs. AI improved shells is pretty close. And although it counts for little, the finished AI shell as a racy look to it.,

For a while there I was on the scent trail of a Cooper. I called Cooper and one if its big dealers thinking I wanted a .223 or 22-250. From these discussions, I understand they are making a lot of AI versions of both .223 and 22-250.
 
I think the 243AI is an excellent round with significant improvements.

Of the three rifle you have the only one that I wouldn't do is the 25-06 which already has an oversize case. The 223AI is excellent and I would think the 7X57 would also be good!!
 
Efficientcy is what it is all about
better use of available case volume/shape
I agree with Sam the 25-06 is near most efficient it can be so with the original parent case to improve would only yield minimal gains
the 223 and 7x57 would probably be a better coice with the 223 being my fave of the two but that is only because I would want a 223 for preds the 7mm would be a different application
I did the ackley route on my 280 rem but as of yet haven't put the barrel on the firearm
peace, out..... /ubbthreads/images/graemlins/grinning-smiley-003.gif
W.E
 
I have had at least a dozen 243 AI's, it is a fantastic improvement over the standard 243 for many reasons. All I have ever used is Remington brass for the 243 AI and PMC brass. Groups with a minimum spec Match chamber with zero freebore are in the 1/4" range with good bullets. Load development with the 243 AI has been very easy with Hart 1-12 twist barrels using 60, 70, 75, and 85 g bullets with only one trip to the range to establish "one hole" groups using Win 760 with CCI250 primers.

In a 28-29" barrel, the 243 AI with a 1-12 twist barrel will shoot the 70's at 3850 fps into tiny groups and at that pressure you will never full length size the brass.

If you bump the load to 49.5g of 760 with the Win Mag primer in a Rem case with the 70's, velocity will be a tad over 4000 fps near a max load which may require full length sizing after the third firing, accuracy still being in the 1/4" area.

I got 3550 out of the 85's in their accuracy node, but copper fouling on this bullet with it's longer bearing surface was twice that of the faster 70's, so I opted to stay with the 70's since all my shooting was 550 yards and under.

Accuracy with the 60g Sierra was in the 4400 fps area using 760, which detonates a large jackrabbit!

My hunting partner and I shot p. dogs while fireforming our brass shooting the 70's with 47.0-47.5g of Win 760 with the Rem brass; CCI 250 primer at 3700-3750 fps grouping in the high 3's.

The only powder that I have ever shot in the 243AI is Win 760 and AA2700 which I interchange with loading data for the lot# that I have.

No doubt that the 243 AI is one of the better Ackley Improved cartridges, and I have had a bunch of them.

 
the highly tapered cases benefit the most. This is relative to MV increase, not case life. ANY case gets better case life with no taper and a 40* shoulder. The ?x57 cartridges and the 6.5x55 etc with heavy tapers pick up quite a bit of capacity. I have a 6.5x55AI right now that is just sweet. I also have the 280AI and 6.5-06AI. Eventually I want a 7 twist, 220swiftAI for the 75-90gr pills.
 
I probably should say that I wasn't out to get the .243, thought I read it somewhere. Was more just wanting to illustrate that some rounds may be better candidates from what I currently own that am willing to use. The .25-06 would probably be a better example one that the improvement may not make as much of a difference.

Between my .223 and 7x57 I would have different reasons for doing it. On the .223 I would shoot it much more (target/coyote) and it is due for a new crown and trigger anyway. Currently trying to modify my bathroom scale to check the pull weight.

On the 7x57 I have fought the throat length and bullet seating since loading for it and it would be a good time to make the throat mod and AI. Plus I am wanting to replace the dies I have for it anyway.
 
Some people don't think the Ackley Improved cartridges do much and that they're not worth it, others think they're great. Course the naysayers mostly haven't fooled with them, but since when does no experience make someone any less of an expert?

Some cases blow out more than others so performance increase isn't gonna be the same with all of them. Some will come to life like you wouldn't believe. Start shooting AI's and you probably won't be messing with the standard cartridges very much anymore.

The .223AI is a really good cartridge. With varmint weight bullets one of these can take the place of a 22-250. And Improving the 22-250 turns it into something really excellent.

I don't shoot a 25-06 and don't know about the 25-06AI or how much you'll gain. But I do have a .257AI, and Improving it makes a noticeable difference to where it will at least equal the 25-06. Working velocity with a 28" barrel and 85/87gr bullets is 3640 - 3775 using about about 50gr. powder.

The 7X57 has a lot of taper. It's the same case as a 257R/6mm and Improving it makes a good difference in capacity. They really wake up. The 7x57 shoots a much heavier bullet and I'd think there wouldn't be as much velocity increase, but that's just a guess.

The .243AI was mentioned by Ackleyman. Listen to him. I have 2 of them and by Improving that case you'll get more accurate velocity with 70's than a standard .243 gets with 60's. That case blows out comparatively less than others and still the increase is plenty enough to make it worthwhile. It's a good one.
 
I have no experience with the A I cartridges but I would think the one caliber that would show the most improvement would be the 250 savage, it has a long taper and would seem to gain quite a bit of capacity.
 
I have a couple 22-250 AI barrels, a mini mauser chambered in 223 AI, and a Winchester 94 30-30 AI and Im tickled with all of them. Yes case capacity is upped, but me being a cheap skate, I appreciate the extended brass life a lot than the speed.

As far as accuracy, Im still not sold on all the "inherent accuracy" thing. I think that if you dedicate the time, patience, attitude and money to any firearm, be it benchrest or varmint- your going to get good results. Is a factory chamber that is set back and opened up to an AI chamber going to be more accurate? That is answered simply by saying "Who is doing the work". A factory barrel rechambered by a competent smith who sweats the small stuff could very well out perform a big name "custom" barrel chambered by a shadetree smith.

With regards to speed, yep its there, but its not free. Everything is reciprocal. You get more of this, but might have to sacrifice some of that, but thats the way with many things in life.
Are the AI cartridges worth a look? Yup, most definately. Is it going to turn your 223 into a 220 swift, or a 30-30 into a 30-06? Nope. But, then again, I dont think thats why they were concieved.

It sounds like the 7X57 is an excellent candidate-You get a good chamber cut to your specs, brass is readily availble, and If your not happy with the outcome, you've got minimal invested. In my humble uneducated opinion, The 7x57AI should have been standardized instead of the 280 rem AI, but Im by no means an expert.
 
The 7x57 AI is an excellent round! The 280 AI gets all the rage but like yotenaylor said the 7x57 AI should have been standardized Vs the 280.
I researched the 7x57AI for several months before taking the leap. All data was based on rifle results, I on the other hand wanted to do this on my Encore pistol for deer hunting. This round met and exceeded my expectations, I chose Hornady’s 139 SP as my deer bullet. My Encore barrel is a Shilen match 1-10 twist 16” barrel with brake. Here are my results, again keeping in mind this is from a 16” bbl. I would guess an increase of about 300 fps for a 24” + barrel. Accuracy is outstanding if I do my part. I can consistently place shots inside a deer kill zone out to 300 yards off steady styx. Recoil is very mild out of the Encore pistol. These results place the 7x57 AI (pistol) in the middle of the 280 rifle velocities in most reloading manuals.

Hornady 139 grain SP
Pact Chronograph set at 10’ in front of muzzle
N550
52.5 grains = 2880 fps - *** Hot
IMR-4350
53.5 grains = 2850 fps – Safe – Maximum
IMR-4350
52.5 grains = 2794 fps – “Pet deer load”

Sierra 120 grain Pro Hunter
Pact Chronograph set at 10’ in front of muzzle
IMR-4320
49.5 grains = 3012 fps – Base line velocity test

I also have a 24” 257 AI and am in the process of load development on my newest barrel a 26” 244 AI. I make all 3 rounds off the parent 7x57 using Remington brass.

Hope this helps

B..
 
Quote:

Hope this helps




It does and so does everybody elses. I think one thing about going AI was that I put too much into the modifyed cases. From what I gather, and anybody please correct me if I am wrong, forming the brass is just done by fireforming the parent case in the new chamber. New dies are needed but after that it is business as usual?
 




forming the brass is just done by fireforming the parent case in the new chamber. New dies are needed but after that it is business as usual?



From what I gather you are correct. I have also taken the plunge into the AI world and with my research and the answers from the guys on here you just shoot the parent brass as usual and when you eject them you have AI brass.

I am currently waiting for my 22-250AI to get back from Dan Carey...I'm not sure how much longer I can wait /ubbthreads/images/graemlins/grin.gif

Good luck, and keep us posted on what you choose.
 
Yes, make the standard case and fire it in the new chamber. With that said there is more to it. Using the parent (7x57) I neck it up to .358 [you could use .308] – then bring it back down to 7x57 in the standard die without the decapper assembly. My die is set to size the case so I have a snap or crush fit ie creating a (false shoulder). I did until recently load the cheapest bullets I could find for fire forming to make the AI case. After reading some excerpts in PO Ackley’s book as well as an article on 6mmBr.com about using cream of wheat for fire forming I tired it and now use this method exclusively. Instead of cream of wheat I use yellow corn meal & tissue paper. [Form the case as described & prime– load 15.0 grains of unique power – fill with corn meal – add tissue paper – and fire in AI chamber = formed AI case]. If you choose this method you really only need the standard sizing die and not the seater too, unless you want to load for the standard, however I do recommend you neck up the parent case then back down to create the false shoulder for proper headspace.
Yes you will have to buy a set of AI dies for the corresponding caliber. I have my FL AI sizing \ decapping dies set to bump the shoulder back .003”, which allows the action to close very smooth with a chambered AI round.

B..
 
On the AI rifles I build, I recommend firing a standard cartridge in the AI chamber, which is already shorter than the standard chamber and will crush fit when the bolt is closed. It's not uncommon to see outstanding groups shot while fire forming cases.
 
The only thing required in taking a standard chamber to an AI chamber is to have the barrel set back at least one thread. This is required because, as ackleyman stated, the head space length on a properly cut AI chamber is slightly less than the parent chamber.

Just running an AI reamer into a standard chamber leaves you with an "AI chamber" that has excessive headspace and the brass will stretch upon firing the first time. With a properly cut AI chamber and a a factory round, the bolt will close with a slight crush fit which preserves the case and prevents case stretching in the web area when the round is fired.

After the round is improved, loading using a set of AI dies is just like loading any other cartridge.

I currently only own one AI rifle - a 257 AI - and as Ackman stated, it will shoot with the 25-06 in velocity, and you have the sexy looking case to work with.

-BCB
 
I have three Ack Imp rifles. Sako in 257 Ack Imp, Rem 700 in 280 Ack Imp and another Rem 700 in 338-06 Ack Imp. All three are a step above the standard and well worth the trouble to load for. I believe you will like the Ack Imp regardless of the cal you chose. First 338-06 Ack, Second 257 Ack, Third 280 Ack

338-06AckImp.jpg


sako1.jpg


aff8.jpg
 
AI-ing the 223 gives you roughly 2.55gr more powder. AI-ing the 22-250 roughly 3.4gr more powder. AI-ing the 25-06 gains you roughly 5.2gr of powder. AI-ing the 243 gains you roughly 3gr more powder......
 


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