Notes on fireforming Ackley Improved cases

[Wayne Smith]

I was reading P.O. Ackley's loading manual the other day it it struck me that he strongly supports using full loads to fireform his cases. In fact, he states that if a light load is used it can shorten the case and change the headspace of that cartridge. This is potentially disasterous. He states cases and shows pictures of rifles blown up by this practice.

This only applies to rimless cases that headspace on the shoulder. With rimmed and belted cases it doesn't matter if the shoulder is set back.

This is old, and needs to be renewed as a warning.

[5Shot]

I have never used light loads to form, but it is good information to keep in mind.

[Sig556r]

I use medium loads to fireform 7.6x39 brass to 6.5Grendel with excellent results...not a big fan of the cream of wheat filler

[Tom W.]

In my 30-06 A.I. I fire form w/ 13 gr. Red Dot and a 150 - 170 gr. cast boolit.....

[stubshaft]

In my 338-06 AI, I form cases from 270 brass. I neck them up to 35 cal and create a false shoulder to headspace on. 16 grs. of Red Dot with COW and a tissue square to top it off forms them perfectly.

[GBertolet]

To fireform my 35 Whelen Imp, 10 gr of Bullseye, COW, and tissue to keep in place. Swab bore and chamber often, as COW is messy. Fired into a stack of magazines in the basement. Works great.

[M-Tecs]

I know I am going to need flame proof pants after this but the P. O. Ackley reference books are the only ones I have not kept and I have hundreds. Just too much stuff that the claims fell short or were flat out wrong. At one time I drank the cool aid but after chambering a couple of dozen AI's in 7 different cartridges I have developed a mild to strong dislike for most of the AI's

[5Shot]

What didn't you like?

[M-Tecs]

I am currently out of town due to my father's health issues. I only have my phone so long answer's are a challenge. Velocities in the books tended to be very optimistic and the velocity gains when improved tend to fall short of P.O's claims. Of the ones I have done the 280AI seems to be the best. The 22-250AI is the one I like the least. Campared to my 220 Swifts the 22-250AI is very dishonest. Pressure and accuracy nods are very narrow with the AI verse the Swift.

[TNsailorman]

Most of the ballistics claimed in the old days were wrong, both by developers, writers and others. They did not have reliable chronographs in those days and used mostly calculations that some mathematician had come up with. I corresponded with him in the early to late sixties and he told me in one letter that the most effective of his improved cartridges was the .257 Roberts AI. He claimed to be able to get almost .25-06 velocities out it when the same length barrel was used. The fact is that most of the later "experts" have a world of equipment and firearms available to them that did not exist way back when. All too often writer would play with the findings of their article by comparing a personal favorite with some other caliber that they want to disparage and quote velocities and data arrived from different rifle with different barrels lengths and powders and bullets. The computers have done a lot of good cleaning up a bunch of these guys and knowledge is greater these days also. This site is a good example of a wealth of knowledge that exists today. In the past there just wasn't any experience, knowledge or gun tinkers in one spot of even available as you can find right here on this site. I have been a happy camper ever since I found it. james

[5Shot]

I am currently out of town due to my father's health issues. I only have my phone so long answer's are a challenge. Velocities in the books tended to be very optimistic and the velocity gains when improved tend to fall short of P.O's claims. Of the ones I have done the 280AI seems to be the best. The 22-250AI is the one I like the least. Campared to my 220 Swifts the 22-250AI is very dishonest. Pressure and accuracy nods are very narrow with the AI verse the Swift.

I agree with all that...the improved cartridges gain VERY little, and I have the king of the letdowns...the 35 Whelen AI. What I do like is that the shoulder reduces case stretch, and it looks cool. There is nothing to lose, almost nothing to gain, but if you want one, you want it. I have never had a factory 35W, so I already had dies, and case forming is a non issue.

[Tom W.]

That's why I have two, 30-06 and 30/30 , both A.I now. I only kill paper. haven't hunted in several years due to health problems, but like to have something different......

[GBertolet]

I had the same experience as 5Shot did. I went to have my rife rebarreled to 35 Whelen, and the gunsmith said he had a 35 Whelen Imp reamer, which would reduce case stretching, and the sharper shoulder would give a better headspace, over the standard Whelen. So I went with that. No way to know what the standard 35 Whelen would have done ballisticly in my rifle, but with the Imp version I can break 2700 fps with the 250 gr Speer Hot Core bullet in a 24" barrel. A moose and caribou both went down, like they were hit with the hammer of Thor. The rifle now is mostly used with cast bullets at the range.

[Budzilla 19]

Full power loads and engrave the rifling with the bullet!!!! Never had a failure doing it this way. But I’ve only done .280 AI so far. More coming later as funds allow

[5Shot]

I had the same experience as 5Shot did. I went to have my rife rebarreled to 35 Whelen, and the gunsmith said he had a 35 Whelen Imp reamer, which would reduce case stretching, and the sharper shoulder would give a better headspace, over the standard Whelen. So I went with that. No way to know what the standard 35 Whelen would have done ballisticly in my rifle, but with the Imp version I can break 2700 fps with the 250 gr Speer Hot Core bullet in a 24" barrel. A moose and caribou both went down, like they were hit with the hammer of Thor. The rifle now is mostly used with cast bullets at the range.

That is exactly why I ended up with my first 35 Whelen AI...that was the reamer the smith had.

[SvenLindquist]

Most AI results in P.O.s' books cannot be duplicated until you go to longer barrels.

Case forming with fast powders, COW and a TP wad works just fine.

You can also shoot non AI factory ammo in an AI chamber IF the chamber is correct.

His books are great reading BUT like most 50 year old info its age should be considered.

And lets never forget that tapered cartridges always feed better. That's why the brilliant Brits made the 300 & 375 H&H look the way they do.

[rockrat]

I have two. A 30-06 AI and a 223AI. The results were good with the 06, but the 223 version was a big improvement. 3600fps with a 55gr vmax out of a 24" barrel. My '06 will go 3100fps with a 168 Zmax, but I do have a long barrel on that gun--29"

[Rich/WIS]

Have a 30/40 AI and fire form with a moderate load of Blue Dot and a 170 cast. The rifle is a Ruger No 3 and the gain in case capacity is about 5 grains of IMR 4064. This puts it between 308 and 30/06 in capacity so significant gains in power are possible in a strong action like the No 3. Unfortunately to utilize the gains means a significant amount of recoil and my standard fun load if pretty wimpy, about 1600 fps with a 311291. For deer I load a 150 gr J bullet to about 2600 which is effective and not too punishing on me.

[GBertolet]

I am drifting a little on this thread, but I find decent loading data for the 35 Whelen Imp almost nonexistant. I asked the gunsmith if he had any data, and he said no. He said most of his clients settled on using 4320 powder though. So that's what I did. This was back in 2001. There are likely better powders now. It was suggested by the gunsmith, that I start at the maximum for the std Whelen, and work up. 56 gr was max for the 250 gr bullet. I incrementally worked up to 63 gr, where I finally started to see pressure signs of lightly cratered primers. YIKES, those P17 Enfield actions are sure strong. Bolt lift and extraction was easy, and minimal effort required to resize the cases. After taking a moose and caribou in 2001, I decided not to further push my luck with those loads. I have shot only cast bullets since in the Whelen.

[5Shot]

I am going to work up some loads with RL17. According to Quickload it should give the best velocity of available powders with 250 grn and heavier bullets. I'll know more after the snow is gone. My initial tests in the fall matched the QL prediction quite close for velocity.

[dh2]

I have both a 25-06 AI and 280Nosler AI , I started forming both with factory ammunition some of these cases are over 7 years old and going strong, the 280 Nosler AI does use some factory cases, after that cases have been formed using the 10Gr. of X700 topped off with cream of wheat .
to reduce the load below the book, sounds like a bad idea in many ways to me even to form a case

[lightman]

The only AI that I have is a 22-250. It was built using a new barrel not a rechambered factory barrel. Case capacity is something like 1/2 grain of alcohol less than the 220 Swift cases that I have measured. The velocity is real close to published 220 Swift velocity and I use 220 Swift loading data to load with. The AI version does seem to stretch quite a bit less. It also does not feed through the magazine as well as its tapered brother does. I use a max load for the parent cartridge for fire forming.

For what its worth, some rifle smiths think you should set the barrel back a few thousands of an inch before rechambering to an AI cartridge to insure getting the correct headspace.

Truthfully I'm not sure the AI thing is worth the cost of additional dies, ect. But its something different which is enough for some of us. I doubt that a Prairie Dog knows or cares that he was hit by a bullet going 4000fps rather than one going only 3800!!

[5Shot]

For what its worth, some rifle smiths think you should set the barrel back a few thousands of an inch before rechambering to an AI cartridge to insure getting the correct headspace.

Truthfully I'm not sure the AI thing is worth the cost of additional dies, ect. But its something different which is enough for some of us. I doubt that a Prairie Dog knows or cares that he was hid by a bullet going 4000fps rather than one going only 3800!!


Yes, the barrel does need to be set back before rechambering. The AI chamber is shorter than the parent by several thousandths. As for any benefit, I would agree that there really isn't any. Wanting one is the only, and best, reason to have one made.

[Wayne Smith]

. Wanting one is the only, and best, reason to have one made.

I would argue with that statement. I strongly prefer a rimmed case in a single shot. I wanted a .25 caliber single shot. I also wanted it to be as close to my old 25-06 as possible. The 25-35 did not make it. The 25 Krag AI does. I'm not sorry I had it made.

[uscra112]

I know I am going to need flame proof pants after this but the P. O. Ackley reference books are the only ones I have not kept and I have hundreds. Just too much stuff that the claims fell short or were flat out wrong. At one time I drank the cool aid but after chambering a couple of dozen AI's in 7 different cartridges I have developed a mild to strong dislike for most of the AI's

AMEN. And one of his acolytes is carrying on the tradition.

[Walks]

I've had .25-06 for 40yrs, an improved for 30yrs. I seat the bullet out to jam into the rifling with a max charge of powder.

I was REALLY surprised when I got a Chronograph a year later and found an an increase of 50fps.

You pays your money and you takes your chance.

[Tom W.]

In my 30/30 A.I. which is a NEF single shot, I normally use 6.6 grains of Bullseye or 11.6 grains of Herco to fireform, with a 160 gr. Lee
309-160-R, an old single cavity, or a 170 grain double cavity Ranch Dog boolit.

I DO have quite a few boxes of "standard' 30/30 loads that I loaded up years ago. They get fired when I have the chance to get to an outdoor range.

The Bullseye loads are fairly light and don't beat me up when shooting them. The cases form just fine.

For both of the above loads I just use Lee dippers.

[Tom W.]

In my 30/30 A.I. which is a NEF single shot, I normally use 6.6 grains of Bullseye or 11.6 grains of Herco to fireform, with a 160 gr. Lee
309-160-R, an old single cavity, or a 170 grain double cavity Ranch Dog boolit.

I DO have quite a few boxes of "standard' 30/30 loads that I loaded up years ago. They get fired when I have the chance to get to an outdoor range.

The Bullseye loads are fairly light and don't beat me up when shooting them. The cases form just fine.

For both of the above loads I just use Lee dippers.

[Wayne Smith]

Tom, the rimmed cases are an exception since they headspace on the rim. This is for rimless cases that can change the headspace if they shrink.

[Tom W.]

Even at that in my 30-06 A.I. I use the afore mentioned boolits and either 13 gr. of Red Dot or 14 gr. of Green Dot to fireform. It works just wonderfully.....

[salpal48]

I current have only 1/ AI rifle. 25 krag improved. i generally do not fire form. my process is to neck up a 30/40 Krag case until almost straight . Them bring the entire neck down and final form In an AI trim and form.. this works for me quite well. . a little more work but as it said better for me

[Stephen Cohen]

I chose the 375 Whelen or AI which ever you call it, I chose it because it gave me a good 375 calibre in a much shorter action than the 375 HH, shells are cheap and easily formed with the cream of wheat method or a cast bullet, those who choose one of the AI rounds for mack 1 speeds are going to be disappointed in most cases. These rounds are called the AI family not the ASV for Ackley super velocity, I guess the message I am trying to convey is the reasons for doing an AI on your favourite caliber are many but speed is not usually one of them. I am pleased with my 375 Whelen and will only surrender it when my time on earth is up. Regards Stephen

[Cap'n Morgan]

I was reading P.O. Ackley's loading manual the other day it it struck me that he strongly supports using full loads to fireform his cases. In fact, he states that if a light load is used it can shorten the case and change the headspace of that cartridge. This is potentially disasterous. He states cases and shows pictures of rifles blown up by this practice.

I can understand why a not fully formed shoulder can be dangerous, but a shortened case is not a problem. On the contrary, an improved case which hasn't shrunk in length could indicate that the case has stretched lengthwise.

I used to make 7x55 AI from 6.5x55 by fireforming with normal loads. The cases would remain the same length or even stretch a little. But once in a while a case would show sign of head separation and had to be rejected. Once I started to use hydraulic pressure to form the cases, the cases would actually shrink to 54mm in length and all signs of head separation was gone.

I guess I wasn't careful enough to eliminate all headspace when fireforming; The front part of the case would then cling to the chamber while the stretching would occur in a narrow band near the bottom where the inside taper starts.

[uscra112]

Yes, what he was talking about was shortening the base-to-gage-line dimension, not the overall.

A dodge that can be used with care when fireforming with light loads is to lightly lubricate the cases. This will let them slip back to the breech face so that the shoulder forms correctly. Thorough cleaning of the chamber afterward is of course mandatory. I've used this with loads of 6-7 grains of Red Dot and a cast bullet with success. I used a light coating of RCBS case lube, which is water-soluble and thus cleans up easily.

[ackleyman]

17 Ackley Hornet
223 AI
22/250 AI
22-243 AI
6/250 AI
6 Rem AI
7/08 AI
280 AI

I work up a load for accuracy that I will be hunting with in all the varmint loads, fire form while hunting.

With big game rounds, I fire form with cream of wheat and bullseye, but I really do not like it. You have to check the cases to make sure no Cream of Wheat is left in the case in the 280 AI. Next firing on the Big Game cases is also a full power load, darn near max in most cases where best accuracy is found.

I have heard of fire forming using slippery cases, but I do not like the idea of a potential mess.

Only the novice will fire form using minimum loads in an Ackley case or non Ackley case, case stretching is sure to folllow on minimum loads...I ruined 500 cases in 6 Remington learning that lesson.

Many gunsmiths have no idea how to head space for an Ackley case, I set mine up short with the ever so much feel on the bolt when I chamber new brass. Case life is indefinite when a chamber is set up with ever so slight case crush.

[Tom W.]

"Only the novice will fire form using minimum loads in an Ackley case or non Ackley case, case stretching is sure to folllow on minimum loads..."


I can't agree with that. I've been fireforming my 30-06 A.I since the late 1980's. I will admit to not having the 30/30 A.I.for a year yet.....

[Wayne Smith]

30-30 doesn't matter - it headspaces on the rim. Same as my 25 Krag AI.

[uscra112]

My first cast-bullet rifle was my Dad's Model 336 - .35 Remington. I learned the lesson about rimless cases pushing the shoulder back when fired with reduced loads the hard way. Being (back then) a rank noob, I accumulated several dozen cases that needed to have the shoulder pushed forward again. Used the "slippery case" method with a modest charge of XMP-5744 with complete success. I'm sure I still have those cases in rotation. Lube used was RCBS case lube. Being water-soluble, it is very easy to eliminate it from the chamber once done.

[Onebad06vtx]

I load for both the 2506ai and 22-250ai and I use a full charge load with the bullet seated into the lands.
I get great accuracy fire forming that way and perfectly formed brass.

[Tom W.]

30-30 doesn't matter - it headspaces on the rim. Same as my 25 Krag AI.

I think you said that once before.