The chase for Ackley Improved.

[High_Speed_Low_Drag]

First time caller long time listener.

I am currently staging to build a few rifles. One being a CZ BRNO Mauser in 25-06AI. Then a 270AI on a Remington 1903A3. I already have the reamer for 25-05 AI and the 06 AI go/no go gauge (All from PTG). I also have a set of Redding Dies for 25-06AI. Anyways. I am going to be ordering the barrel and brake soon and start.

I was wondering if anyone here has experience on either or both AI cartridges. You can leave out the whole barrel burner crap and all that. I understand how they could do so but I also don't shoot as avidly as most or as much as I would like so I doubt it's gonna go quick. If it does well I have the equipment to rebarrel. It's all part of the game.

Appreciate any and all useful info.

[HiBC]

OK.
I have built AI in 257 Roberts and 30-06.
I am quite satisfied with the results.
But,there is the part about fireforming brass,etc. So,for many folks,its more practical to build a plain,non-AI 25-06 vs a 257 AI

I look at it this way. If ,in the slower burning powders,case capacity is a limiting factor....if "compressed loads" are a limitation,then IMO,the AI route may give a good return on investment.
But,if using 4350 or 4831,pressure dictates a max load at an 85 % full case,I just do not consider looking for more case capacity.I can't use all I have.

Something else is true about my AI experience.I built the rifle my way. I fiitted the locking lug engagement. I headspaced it. After about 500 rds,I re-checked the "feel" of just contacting the "go" gauge.
I do the paper clip check,etc.I buy my brass in 500 lots,my powder in 8 lb kegs.

And I recognize there is no free lunch.In large part,the "Improvement" in velocity using AI cartridges is about loading to higher pressures than can be recommended.I admit that.
That means you are closer to the edge of the cliff.That means you are operating at a narrower (if any) margin of safety. To a degree,care,limiting variables,etc can make the risks more controlled.But Murphy's law is always there. As I got older,for some reason I backed off my charges.

Now,one more thing. Overbore versus expansion ratio.

You have combustion chamber volume. You have powder volume. That powder will turn to gas,which expands. Pressure goes up.

If you had the bore plugged at the throat,the gun would be a grenade. No place for the pressure to go.

If you have a straight wall cartridge,and a strong gun,its hard to blow them up.
You can with pistol powder,or something,but because the bore is large,combustion chamber volume grows a lot as the bullet moves down the bore.Pressure moderates.

When you have a small bore and a big boiler room,the bullet moving down the barrel provides a smaller percentage of combustion chamber volume increase.
So,pressure goes up.
You get in trouble quicker using big cases and small bores. Spikes happen.

I'm not telling you a 2506 AI is a bad idea. Go for it!

But when you find the edge,it might be sudden,without much warning.
Don't give up too much safety margin.

We have evolved a lot regarding chronographs,trajectory knowledge,ballistic softwares,rangefinders,target knobs,reticles,etc.

We outgrew the Weatherby idea of screaming velocity solving everything.

Folks shoot 1000 yds with 2800 fps or less.

But DO have fun,do things your way,stay safe.

[High_Speed_Low_Drag]

HiBC, thank you for your reply.

I am wanting to build a few AI just to say I have done it and for the experience of owning one and learning it.

I know going in I have a smaller margin area of safe operation which I will have to do my due deligence to find it and do so in small increments.

I also agree that velocity isn't the answer. Like you said we have moved on past the Weatherby theory.

My main reason for wanting to do this build is on the concept of it being a slightly larger scale version of a 220 Swift. Being able to use heavier bullets and push them as fast as possible. With 220 Swift brass being hard to find at times and not really wanting to build another .224, I figure the 25-06 AI will cure my itch. The 270AI I plan on building is to achieve the same thing with just slightly heavier bullets the the 25. It will also help round up my collection of 06 guns (25-06AI, 6.5-06, 270AI, 280, and 30-06)

I am hoping for more people to chime in. I again appreciate it HiBC!

[HiBC]

When I did my 30-06 AI,I found out there is a specific headspace gauge for the AI.
Remember,when you fireform,you want the case head snug against the bolt face or you will get stretch rings.
Initially,with non-AI brass,you only have a circle/line contact brass to chamber at the junction of the neck and the shoulder.

One thing for sure! Both the CZ and the Springfield are controlled round feed. You do not want to single load into the chamber and force the extractor to snap over the rim.That places way too much load on the limited headspace feature you have on the brass.It will crush back.
You must load to the mag box,and let the round feed up under the extractor.

FWIW,in my .257,I use the 115 gr Ballistic tip for everything,though there is a Berger I have not tried.

You may have different results with the larger 06 case,but the powder I use in the .257 AI is H4831 SC.

[Scorch]

Couple of things you will see in your AI cartridges:
* Large capacity, straight wall cartridges don't see much improvement in velocities. Most of the gain you will see is in headspacing, which will translate into extended case life.

* With modern powders, neither will be any harder on throats than the factory versions of the same cartridges.

According to the man himself (PO Ackley), the cartridges that benefit the most from improving the case are cases with a lot of taper to the body. In my experience, the prime candidates for AI are 22-250, 250-3000 Savage, 6mm Remington, 257 Roberts, 7X57, 300 H&H, 375 H&H, etc, all of them are longish tapered cases.

[taylorce1]

P.O. Ackley didn't see any point to trying to improve the .270 Win, pretty much said you couldn't improve it.

I'm not going to say what your doing isn't worthwhile. However, realize you may not see the results you're expecting. If you treat it as a learning experience, then what you learn is never a bad thin. I sure wouldn't build two rifles in an AI cartridge at the same time. Build one, spend some time with it and then decide if it is truly what you want to pursue.

[High_Speed_Low_Drag]

HiBC: I appreciate the info on not single feeding ammo. I will remember that for sure.

I have both of ackleys books and I have seen where the 270 and 06 he said didn't gain enough. But I take it with the concept of modern powders and load development.

I have a Chinese action I am gonna build a plain 257 Roberts on for actual practical use.

I don't plan on building them both at the same time but I have my heart set on 270 AI. But it may change.

[Tinbucket]

The only thing limiting improvement in velocity and follow on development of bullets to fit the velocity is nay saying and those who thing the .30-40 is the bees knees.
Go for thee .25-06. It's already been done to a point.
There is one group with huge cases shooting 270 grain bullets over 4,000 fps. and upt over 400 grain bullets near that. Using H&R Handy Rifle actions and shells more akin to metallic shotgun shells. I'll try to retrieve a link unless someone beats me too it.
I see the problems with extreme performance, as short shell life, and bore errosion.
All the other stuff is juts details such as expensive to shoot.
Dyna Bore coat won't last forever and will have to be redone but the limited feed back indicates it works.
Then there is of bores and the use of expensive metals such as in the Stellite etc.
So lea the way. A solid .25 bullet at a bout 5,000 fps sounds good.

[old roper]

Sierra has loading data for 25-06AI,30-06AI and 257AI and some others. Nosler also has loading data for 30-06AI,257AI,22-250AI.

I'm shooting 222AI,243AI,35 WhelenAI and wildcat 280AI and SAMMI Spec 280AI.

I've done few others. I also post on LR hunting site and one poster is shooting 270AI. You can become member on that site and he's help you and I think he has 1/9 or 1/8 twist for the 170gr Berger VLD.

Myself I would use Sierra data for 25-06AI,

[Stats Shooter]

One thing about the AI's in Mauser and 1903's is that the squares shoulders will require some feed ramp work setting them (grinding) to get things to feed smoothly.

The 25-06 is an impressive cartridge already and with an AI you basically are creating a non-belted .257 Weatherby w/o having to deal with the belt. It isn't a bad idea at all. There are some AI cartridges that to me make Zero sense. Simply because there already exists a cartridge in the same caliber, and same action length that doesn't require the brass forming or squared off shoulders....But the .25 cal really isn't one of them.

You may consider getting the barrel 28" or so, and then if you shoot it out, just cut 2" off at the threads and re chamber with your same reamer. It is the throat and first inch or so that wears out quickly. The rest of the barrel will look like new after only 1k rounds in a .25-06 while the throat and first inch or two will look like 10 miles of bad road

[Gunplummer]

If you want to play around it is fine, but it won't do anything for accuracy. About 30 years ago I was at the range with a 30-40 Krag sporter I had re-set the stock on. These two guys showed up with ground hog rigs. Both had fluted stainless barrels, synthetic stocks, and high end scopes. $2500-$3000 easy. I shot against the one guy which I think had a 22-250AI. Anyway, it was some kind of AI. 3 rounds each, @ 100 yards, same target-bystanders as judges. It was sad. I put 3 shots inside his group. That Krag would shoot 3 shot groups that you could cover with a quarter all day. It might be fun to do, but I would not expect a whole lot out of it.

[old roper]

I always hear tales of shooter with older rifle out shooting someone with custom.

http://s781.photobucket.com/user/tah..._0902.jpg.html

Left target is 243AI. I posted that some years ago on Nosler site. All the years I've been shooting at a range, never had anyone come up and want to get into shooting contest not that I'd do it.

[Damon555]

I really don't see any practical purpose for an AI cartridge....but to tell you the truth I like them....just from a "something different" point of view. I've got a 223 AI and am planning on a 22-250 AI. My 223 AI is an excellent shooter.....but as mentioned improving the cartridge won't make it any more accurate.

If you want one go for it. They are fun to work with.......I've been frequenting gun forums for 20+ years and have grown bored with reading the same things over and over again.....talking AI's, precision hand loading, varmint hunting, long range shooting and shooting steel with handguns is much more interesting than the droning on and on about the same old stuff.

The 25-06 AI sounds like a blast.....and how about instead of the 270 AI go a little more practical and build a 6.5-06 AI or 280 AI? I bet you'd be well pleased with the bullet selection. In any event let us know how it turns out PLEASE!....anything to be the slightest bit interested in reading a thread that isn't rehashing an already beat to death topic!

[Stats Shooter]

I didnt read every post, but I didn't see anyone mention that the AI cartridges are more accurate. I think anyone who knows anything knows that the purpose of the AI was to wring all the velocity possible out of a cartridge without doing any modification except reaming the chamber for AI. In fact, PO Ackley ensures his readers that an AI chamber must be able to fire the standard Cartridge also.

But I digress, the AI concept is fun for those of us who have several standard cartridges and want something new and a bit unique.

As an aside, PO Ackley once said if he could have only 1 cartridge for all North American big game, it would be the 222 Swift due to the super high velocity shock achieved at over 4,000 fps creating a massive wound cavity.

[old roper]

I may be one of the few but that 243AI has Hart barrel and I also have 243 with Kreiger, My 222AI has K&P barrel and my 222 has Broughton.

I expect the same accuracy on anything I build. Just because it's Ackley doesn't mean it can't shoot small group. I look at the velocity as a plus with AI. My 222AI I shoot PD fire forming cases.

The OP going to chamber his own rifles and hoping GP wasn't commenting about him not knowing anything.

[Gunplummer]

I indicated no such thing. I am just saying "Improved" may not result in improved performance. I have only ever had one rifle that I loaded at the top end and got better performance from doing it. I don't get into range challenges too often, most of the "talkers" back out.

[HiBC]

Many of us have seen the guys who show up to the range with multi-thousand dollar rifle/scope outfits ...
And they had a difficult time with sighting in.The scope cannot adjust for closed eyes and jerked triggers.
Their 338 LapuaArctic Warrior with the 6.5-20X Schmidt and Bender on it is ready for elk season if they get a 6 in "group" at 100 yds sort of centered on the target.
Then there is the older gentleman who shows up with his venerable M-1 Garand,iron sights,sits on the ground next to the benches,slings up,and puts 8 rounds in the 10 ring.
In both cases,in nearly all cases,the shooter is the greatest variable in accuracy.
I give P.O.Ackley credit,with the massive wealth and resources your typical gunsmith piles up,he at least tried to isolate variables and do some testing to back up his ideas.
No,not perfect...and no,not always correct...but he tried.And,IMO,he contributed.
I have been quite satisfied with the accuracy out of my AI's.Would I claim the AI is more,or less,accurate? No!
And even if an outfit like AMU,or Precision Shooting,spent $50,000 and a lot of hours and ammo testing and publishing results...If they came to the conclusion that the AI tended to be 10% better,or worse,for accuracy,it would only raise the question "Why?"
It might be as silly as the reloading dies tended to make more concentric ammo with one version or the other,and so the actual factor would be ammo concentricity versus some benefit of shoulder angles.

We really mislead ourselves and others jumping to conclusions over "The day we outshot a Nesika Bay ,Bartlein barreled ,Borden stocked bench gun with our trapdoor springfiels 50-70,proving beyond all doubt pig lead and black powder are superior.
Or that because ,in our hunting camp,three different 35 Remingtons killed 12 deer and proved 10 gauge slugs kill dead deader...
And 35 years ago company "X" made soft brass,so all their brass is still soft,
and "Twenty years ago,"XX"primers were....

IMO,with for example,one 6.5x55 AI rifle you get exceptional accuracy...great!!
That does not mean the next 6.5 x55 AI rifle will outshoot the standard 6.5 x 55 you build after that.

My unfounded guess? the accuracy potential between the AI and a standard cartridge will vary between parent cartridges,and will remain small and inconclusive.
Brass life may be better on tapered cases.
Barrel life? Don't forget fireforming is rounds through the barrel.500 rounds shooting rocks fireforming cases is good fun,and its practice. But itsstill 500 rounds of barrel life.
Higher velocity...MAYBE a modest gain to case capacity,like a few inches barrel length..
Big gains? Well,the AI guy might be loading his 257 AI to 68,000 psi while the regular .257 R guy is loading to a SAAMI reloading manual spec of,what? Maybe 55,000 psi?
Folks generally we can get more fps at 68,000 than we can at 55,000.It has nothing to do with a sexy looking cartridge case.

That said,I really like my 257 AI. But there is no "magic"

[Stats Shooter]

There is one point that gunplumber illuded to, but didn't expand upon.

There is no guarantee that with your AI, the best accuracy will occur at or near the top end. Take for instance the .280 Remington vs the .280 Remington AI. The velocity improvement comparing identical Barrel lengths, and powder type/brand is about 3.5%, or about 100 fps from 2700- 2800 with a 160 gr bullet. It varies changing bullet weights of course and powders, it the 3.5% mostly holds.

But how often do we get the most accurate load near the max? It does happen, but not frequently. You could make the case then at least the AI gives you more velocity potential to find that accuracy node, and it may well be higher than the standard cartridge.

[Gunplummer]

I had no idea what the original poster was about. If you want to "Hotrod" AI is the way to go. Try some Weatherby cases where the shoulder radius really chokes the charge behind the bullet. I have nothing against PO Ackely. His experiments are definitely well recorded and I have found most to be true.