30-06 Ackley Improved, anyone converted one over?

[1hole]

While I can see some benefits for a very tapered case such as the .250 Savage, I don't think there is enough volume difference between a standard .30-06 and an improved one to make much of a difference at sane pressures.

Some 55 years ago when most rocks were still hardening Mr. Ackley wrote a monthly gunsmithing column for a gun magazine, GUNS & AMMO, IIRC. In answer to a question, "Which of your AI chambers worked best?", he said the .250 Savage was best and most of the rest really didn't make enough difference to make a difference; that killed my desire to AI my beloved .30-06. And I'm still glad I listened to the master about it.

Sure, we can fire factory -06 ammo safely in it but the pressure would be low so velocity and trajectory will be poor and accuracy probably wouldn't be great. Any resale value of an AI rifle would likely be very low too.

Ackley's really aren't very popular, handloading would be necessary and we are a very small group. Which of us is going to be interested in buying a used hunting rifle that has probably been hot-rodded all of its life?

Bottom line, I figger if God wanted me to shoot a .300 mag that's what He would have led me to purchase to start with.

[archangel2003]

Deleted

[archangel2003]

I have a heavy long range competition rifle built up in the '06 AI with a 31" barrel that was made with the goal of sending 175 grain MK's out at 3000 fps with H4350. It did that, but grouped better with 190's at 2950 using H4831, so that's what I settled on. Won a couple of 600 yard matches with it once upon a time.

It really comes down to what you're trying to do. In a more standard length barrel, you'll probably pick up 150 to 200 fps over the unmodified round. My Pop and I did a handful of different AI's in our Highpower days. If you're shooting a lot and have time to shoot once to blow the cases out, then reload them to work up the load for the Improved case, then load them AGAIN for final production. . .well, you may have noticed that premium, factory, jacketed bullets are experiencing a bit of a shortage of late. . .

Then there's things you can do with the standard round with a longer throat. This was how my hunting 30-06 came from Remington luck of the draw and the magazine + throat allow me to seat my .470 BC 168 grain Barnes TTSX's well out of the case and run with a healthy dose of H4350 that is off the reservation for "standard" COAL's. That's running at 2975 fps and I don't feel disadvantaged about it not being an Ackley or a .300 Win Mag.

I went through the "new hunter" phase of envisioning cross-canyon shots at flyspeck-looking trophy bucks, then realized that my deer were getting shot at under 200 yards. The 24" .30-06 with the 4.5-14 is now an 18" .308 with a 2.5-8. Your mileage may of course vary.

The 30-06 I have and am thinking of converting is an older sears branded Winchester Model 70 that was a hand me down that looks like it was purchased new yesterday, and I have no intentions of ever selling it.

[FLINTNFIRE]

If you wish to convert for a reason you have then do it , I myself have wildcats in some for reasons that former owners had or had to and I have some I have had made for reasons I felt made sense or I wanted to .

At the end of the day it is what each person wants or feels the need for , maybe some want something in between a 06 and a 300 mag if so , well so be it .

It is like the so called magical 6.5 whatever latest flavor of the moment , already one out there can already do it but whatever people want or the latest craze is and whoever wants it has the right to it .

[Lloyd Smale]

ive done it. Had a 250 improved and a 257 roberts improved. I did the 250 owning a 257 and did the 257 owning a 25-06. So i didnt do it because i had one gun and needed more power. I did it because it was something new to play with. I think we all know the 06 stands on its own as one of the most versitile chambering ever made. My thoughts today are this. take an 06 and make it into an improved. You might gain a 100 or 200 fps. Nothing wrong with that. But what you gain on the top end you loose if you want to down load it on the bottom end. that to me isnt even a game changer because i have many smaller 30 cals to use if i want less power. But what i ran into was when i got bored with it and wanted to trade for a different gun it was a long process trying to find someone interested in the improved guns. I can see there reasoning too. Most hunter are not handloaders. Most hunters wanting to drop 800 bucks on a new rifle and want more power then an 06 are much more apt to do the logical thing. Buy a 300 mag. ME today? I dearly love the 06. its probably my favorite rifle round and it does a bang up job on about any non dangerous animal in the US. Other then being different or wanting something new to play with it just doesnt make sense. It was something more often done 40 years ago when people only could afford one or two guns and they didnt have the vast selection of chamberings and new guns that we have today.

[elk hunter]

I have Model 70 in 30-06 AI. I bought it that way, because it was a Model 70, and can say I don't see any real improvement over the standard 06. With the slight increase in case capacity you need to use more powder to get back to the original velocity. To increase the velocity over the original round you have to load to higher pressure. With most AI improved cartridges you may gain something like 8 to 10% increase in case capacity and you will get a velocity gain of 2 to 2 1/2 % at the original pressure of the parent cartridge. Simple physics. To get significantly higher velocity you have to load to higher pressure. If it were possible to get 300 magnum velocity's out of the 30-06 at reasonable pressures there wouldn't be that big fat 300 magnum case. I just don't see any advantage there. I also built a 219 Zipper AI on an 1885 Winchester. According to Ackley's book it approaches the 22-250 for velocity. Sorry, the best you can get out of it is about 3200 fps with a 55 grain bullet, in other words it's a 223 with a rim. Any hotter loads and extraction becomes problematic. I don't want to discourage you from building a new/fun project, I too enjoy them, but I try to be realistic in my expectations and try especially hard to not quarrel with physics. Good luck, let us know what you do and post pictures.

[Bigslug]

The 30-06 I have and am thinking of converting is an older sears branded Winchester Model 70 that was a hand me down that looks like it was purchased new yesterday, and I have no intentions of ever selling it.

Kinda depends on your mission then, but it's worth considering. . .

* Some of the greatest military sniping feats in history have been accomplished with the standard '06 - often without even match ammo.

* You can often get a bit beyond common book velocities with careful loading and selection of the right powder, and higher BC modern bullets can flatten the trajectory further.

* Modern optics and rangefinders can somewhat mitigate the need to flatten trajectories with higher speeds.

Just saying that if you're jumping in, do so with eyes open. The .30-06 ain't broke, and the AI treatment is a lot of work for results that could arguably be accomplished more easily by either a .280 Remington (higher BC) or a .300 Win Mag (greater throw weight)

[Jim22]

Yep, I had one built on a 1917 Enfield using the original 5 groove barrel. Back in the seventies. Bud Liebing in Palmer, AK was a fan of Ackley's work and had the reamer. I killed a caribou and a moose cow with it. I did not have a chronograph in those days so can't comment on velocity increase. It used a couple grains more powder thaan the reegular '06 did. One thing I learned was that the rechamber pretty much killed resale value. Anyone would buy a used '06 but almost no one would buy one in '06AI. It's not something I would do again.

I couldn't get an AI die set so I just neck sized using a .300 Win Mag sizing die with an eighth inch or so cut off. Any larger seating die will work.

Jim

[archangel2003]

If you wish to convert for a reason you have then do it , I myself have wildcats in some for reasons that former owners had or had to and I have some I have had made for reasons I felt made sense or I wanted to .

At the end of the day it is what each person wants or feels the need for , maybe some want something in between a 06 and a 300 mag if so , well so be it .

It is like the so called magical 6.5 whatever latest flavor of the moment , already one out there can already do it but whatever people want or the latest craze is and whoever wants it has the right to it .

I do think there may be something with a shorter but wider cartridge case where the powder resides, and long, skinny, heavy bullets with a higher BC do seem to carry out a lot further, but who knows what combination is in the end, ballistic perfection.

I already have an AR in 308, and a 300 BLK single shot H&R (I still want to relabel the barrel 300 Whisper) as well as a semi in x39 and a couple x54R both bolt and semi so I have at least a few 30 cal rifles.

More than a few postings I have read reported no loss in accuracy when shooting stock 30-06 rounds in the AI chamber, and as of yet have not seen any claiming worse accuracy.
What say the AI converted guys?

I would think that if they want to shoot stock 30-06, but do not reload, and accuracy is no worse than stock, it should not be a detriment to the gun, just a quirk, and the brass will of course only fit your gun.

[littlejack]

archangel
I don't have any expierience with the 30-06 AI, but I had a model 98 BO Mauser rechambered to 8mm-06 AI. The chamber was cut with a 40° shoulder, which was preferred by P.O. Ackley. The cases are very easy to make for this AI cartridge. I can take a fired 30-06 case, prime it, drop in my powder, seat my 8mm bullet of choice and fire. This can be done with either annealed or non annealed cases. Ackley designed his AI chambers to be cut .004 short of the parent cartridge. This allowed for a crush fit to fire form cases, with no headspace.The results are a perfectly fire formed 8mm-06 AI case. Then, I check for proper length, or true up the neck. I had the throat cut for 200 grain bullets. A few years back, I shot a few 5 shot groups @100 yards with Norma 196 grain Vulcan bullets. The best group could be covered with a quarter. Chronographed I get a solid 2800 fps with the 200 grainers. I took it to Alaska on a moose hunt, but alas, I never got a shot. Oops, sorry for rambling. I hope your endeavor succeeds.

[Bigslug]

Re: Post #29. . .

You may not realize your BEST accuracy with your fire forming loads simply because they aren't really a load you make to test, tweak, revisit, or repeat. That said, an accurate rifle with a good Ackley load is perfectly capable of being same with a good standard load. I want to say my Dad and I did a total of five different Ackley chamberings across five or six different match barrels and one milsurp sporter '03, and all of them turned in acceptable results at both stages of case development.

Other than the capacity boost, a theory in favor of the Ackley body shape is that you may get longer throat life because the sharper shoulder tends to compress the powder at the neck and burn more of it IN the case, rather than sandblasting it down the bore.

I've had accuracy hovering around a half-MOA from quality rifles in both standard and Improved '06, so I will not come out and say the Ackley has any extra magic in that area. Build either one right, and they both deliver.

[Larry Gibson]

Unless one has a long magazine capability to seat 180 gr and + bullets out farther (such as the older M721 and M1917 actions and 24 - 26" barrels (the M721 came with a 24" and the M1917 a 26" barrel) any improved cartridge really doesn't gain much. With modern actions and 22" barrels in 06 simply loading the 06 to 62,000 psi will get as much improvement as probable.

A better "improved" cartridge for either of the mentioned actions, especially for the M1917 with a 26" barrel, is the 30-06 Gibbs. The Gibbs chamber moves the shoulder forward giving the 06 case a .308W length neck with minimal case taper. if also throated so bullets can be seated to magazine length. That improved case capacity enables the 06 Gibbs to equal 300 H&H velocities with the same weight bullets. Back in the '70s I chambered a couple M1917s to 06 Gibbs and had the chronograph to prove it. With 180 gr bullets velocity ran right at 3,000 fps and 2800+ with 200 gr bullets. That's a worthwhile improvement, if one wants it, over the 2750 fps I push 180 Hornady SPBTs out of my M70 '06 with 24" barrel.

[fatelk]

I have an older Model 700 that I bought a couple decades ago from the son of an old timer gun tinkerer I knew who had passed away. It had a custom barrel on it, in 30-06 AI. I got it for the price of the action, and planned on having it rebarrelled to something else, mostly because I didn't know the quality of the barrel or who did the work. A custom/customized gun is a pig in a poke; you don't really know what you're getting.

It shoots so well that I left it as-is. I haven't shot it in years though. As I recall, it shot fine with regular -06 ammo, when I was fire-forming brass. Regular ammo was always a tight fit, took extra push to get the bolt closed. I found out later that this was intentional, due to the way the chamber was cut. I never did buy any AI dies. I already had a set of Lee collet dies, and found that they work just as well on AI brass as they do on regular 30-06 brass.

Speaking of tight chambering, a long time ago a friend of mine and I were talking, and he asked if I knew why his .243 rifle closed so tight. I looked at it, chamber a couple rounds (they were tight), but couldn't figure it out until I saw some empties he had in the box with his live ammo. They were clearly AI. He said "Yeah, always wondered why they came out like that."

He had bought it used many years before, hunted with it every year. He didn't reload, always factory ammo, and he said it shot fine and always hit what he was aiming at. I offered to help him get set up to load for it, but he wasn't interested at all, said he'd just continue to use it as he always had.

[1hole]

A better "improved" cartridge for either of the mentioned actions, especially for the M1917 with a 26" barrel, is the 30-06 Gibbs. The Gibbs chamber moves the shoulder forward giving the 06 case a .308W length neck with minimal case taper. if also throated so bullets can be seated to magazine length. That improved case capacity enables the 06 Gibbs to equal 300 H&H velocities with the same weight bullets. Back in the '70s I chambered a couple M1917s to 06 Gibbs and had the chronograph to prove it. With 180 gr bullets velocity ran right at 3,000 fps and 2800+ with 200 gr bullets. That's a worthwhile improvement, ....

The Gibbs .30-06 modification is a worthwhile improvement.

IMHO, as a gunsmith and wildcatter/experimenter, P.O. had no equal in his day. By his own admission, P.O.'s "formula" for improving cartridges worked well for a few cartridges but not so well for many others. The .30-06 Ackley is one that he didn't much care for.

[archangel2003]

30-06 Gibbs

Ok then, looking up the 30-06 Gibbs
I am guessing it needs special Reloading dies.

[RayF]

I agree with the power aspect not being worth it in 30-06. I briefly considered 30-06AI, but bought an annealer instead. I’ve never had a 30-06 case crack or lose neck tension before the primer pocket started getting loose. I’m getting a minimum of 8-9 rounds with Winchester, R&P, etc. I’m at 12 rounds with Lapua and they’re still tight as new.

That pretty much dismisses both reason’s I’d do it.

[archangel2003]

The 06 Gibbs looks impressive but the procedure to make the brass is a muti step process.

[Larry Gibson]

The 06 Gibbs looks impressive but the procedure to make the brass is a muti step process.

Back when the first conversion was done pre arrival of the custom dies, we used once fired M72 cases that were FL sized in 06 die then the case mouths ran over a 35 cal expander [these days I'd just FL in a 35 Whelen die]. Then the necks were sized back to 30 cal in a .308W until the false shoulder was a crush fit in the Gibbs chamber. A 311284 cast hard (linotype) was sized, lubed and GC'd at /312 then seated backwards so the GC was firmly against the leade when chambered loaded over a charge of Unique sufficient to fireform the cases. Cases were also lubed with lanolin during fire forming. First 100 cases fireformed perfectly. We then seated 180 gr and 220 jacketed bullets over 4831 and developed some excellent loads. Can't remember whether the 06 dies were from RCBS custom or C&H. Finish reamer came from Clymer who stated which make of dies the chamber would match.

Sounds a lot more complicated than it was. Actually, it was a fun and interesting project that turned out a few very good elk rifles. As I recall a couple of them used a .308W NS die to NS about 7/8 of the neck length after initial fire forming. The Gibbs case would just fit up in them.

[TNsailorman]

I am not now or ever been an "expert" but never let that bother me when I got a wild hair idea. But those days passed with my youth and they are now gone forever. Back in the day I got interested in the improved cartridge idea. I wrote the "man" in his day about inproved cartridges and to my surprise got an answer from him, Mr. P.O. himself. After several letters back and forth, he wrote me one final letter in which he stated that a lot of the cartridges he had "improved" had in the long run been disappointments to him. The one that he said was the best one in his estimation was the .257 Roberts, which gave near .25-06 velocities with a lot less powder and increased barrel life. He called the improved cartridges that he did like in this manner, "they were more effecient" which was the most important thing to him. He never defined "more effecient" in his letters but I assumed he was talking about economy which was really inportant back then. He described the .30-06 improved as not worth the effort as he had developed a shorter version of the belted .300 magnum that used less powder but with the same results. I had a lot of respect for the man and still do to this day as he was a little ahead of his time. The things he lacked was modern day electronic equipment to more accurately record and evaluate his work. just my opinion anyway, james

[edward hogan]

I found the .338/300 win mag in 2002. Very easy to "improve" the .338wm chamber to take that necked up .300win mag case. Incrediblly versatille and allmost the equal of the .340wby.

I decided to abandon the .300win mags I owned. Rebarrelled them so as to never have a ctg mix-up. Improved a couple of .30-06s to AI with 40deg shoulder. In Alaska, not much reason to shoot anything under 180gr in an 06 for game applications. Used my 200gr SMKs in the .30-06AI and also a box of Hornady 220gr RN. The 06AI is a super ctg and more versatile than the plain .300win mag when loaded with heavy cast or jacketed bullets.

Never had any case-life problems from any 06 based ctg. Did have a .35 Gibbs for a while. Would really like to find a .33 Gibbs, but I converted a .338-06 to AI recently and having a .338 gr NEI rn mold that drops ww alloy at 315gr or so, I am satisfied with bullet range for my ,338 cal chamberings.

The .280AI seems to be optimum for a deer or mountain rifle. I have done AI conversions on 6mm International, and .308win as well. For woods carry in Alaska, the .338-06AI is about perfect. If activelly hunting bear, which I don't do, woulld choose my .338/300win mag. Had the .375ruger been around in 2002, would have done a .338/375. Belted magnum is super easy for conversion though, as your belt controllling headspace is already present.

What's reallly fun is doing a switch-barrel gun. The one ctg that is practically a factory AI design is the .284win. One rifle with a .6.5/284 and a .338/284 barrel would do about everything a guy might need. Interestingly the last hardcover Hornady book shows the .30-284 and .30-06 share same load data and ballistics. 35deg shoulder is standard on the .284. Just so much easier to use 06 brass and do a .260rem AI or standard because of the brass scarcity for .284win. Would chose a .358 or .375 necked up .284 over an AI whelen or .375-06.