is going to Ackley Improved worth it?
 

I have a beautiful rifle built on a mauser action in .257 roberts.
Would I need to replace to barrel to go AI and is the investment in a quality gunsmith worth the gains ?

your not gaining much in performance....but if you want/need a wildcat then so be it....reamer...no barrel replacement...the investment in a quality gunsmith is always a must!

You will gain approx 100-150 FPS
Case stretching is almost non existent.

Down side is getting them to feed reliably. Suggest trying some dummy rounds. Usually requires fiddling with receiver and if not done properly ruins feeding . Once done can’t go back

No need to replace barrel just set back one thread and ream to improved chamber

The very wise Dean2 would warn you that AI cartridges can have feeding issues that their parent cartridge does not have...something to think about for a small gain of +100-150fps. Oops, I see fps typed faster than me.

If your rifle is any sort of classic piece you will reduce its value by modifying it.

Suggest you don't,

As others have mentioned there is a minimal gain, I recall a couple articles (Kenny Jarrett as I recall) where PO Ackley himself felt the 280 AI was the only one that really was worthwhile,

If you have to have one (I know the feeling as I have a 280 AI) I suggest getting a Remington donor action, generally easy to find and relatively cheap and getting it rebarelled, more money but you wont regret changing your rifle

Whatever you choose good luck and have fun,

I have a 7-08AI and likely the gains aren't 'worth it' but I enjoy it. Its a bit different, the case life is great without the need to trim much at all. A bit of extra ability to load, though currently the rifle is my wife's and loaded down to below 7-08 max loads anyways.

In the end its probably tough to justify being 'worth it' but I'd likely do it again just as a bit of a fun thing to play with.

Ackley improved alterations that show reasonable gains from what I have experienced are. 250 - 3000 Savage, 7 X 57 Mauser and the 30-30 Winchester, the most noticeable improvement is the longer case life as trimming is all but eliminated when full length sizing. Velocity gains in the three mentioned chamberings can vary significantly depending on barrel length.
I would however caution anyone considering the improved chambering in a classic old rifle that the increase in velocity is offset by the devaluation of a nice old rifle. But that will never stop the hot-rodder's from doing what they do. D.H.

I personally wouldn’t bother, but some people want to squeeze out every FPS possible from their cartridges. If your chasing velocity and want something to do all the power to ya!

Thanks for the great input everyone !
I will not be going forward with it.

Good decision. The guys have u excellent advice.

will help
 

If you ever decide to sell it to leave it as is.

Having a 280AI built as we speak.
So looking forward to it!

I have one and it works well with 150gr Nosler LRAB's

Good to know. I bought a box of the regular 150 AB's to try.
Also have a box or 2 of 140 ttsx...

choices
 

lads

I see lots of advice for the OP, I don't see anyone who has owned a 257 AI helping this fellow make a decision about his rifle. i had a converted Win model 70 XTR in AI, was a fantastic shooting rifle. loved 110gr Accubonds and a healthy dose of IMR 4350...
Next to my 25-06 Sako and my 250 Savage it was a fabulous rifle. ...FS

Interesting to note the 257 is on a 7x57 parent case.......

so is
 

The 6mm Rem

history repeats itself
 

The AI's attempt to move up a caliber in performance ie a 250AI becomes a 257 Roberts,the Roberts becomes a 25-06 the 25-06 becomes a 257 WBY same as the other caliber progressions.You see the same trends in shotguns lengthening shell length to increase payloads.Now a 3" 28ga ?I wanna be a 20 ga? The 12ga 3 1/2" impersonating the 10ga etc.To each their own but it becomes redundant at some point IMO.

Somecgeads would explode if those guys actually knew what they were running for pressure their favorite load was actually run through a pressure gun!
Cat

Not sure I’d go AI. Custom hand loads can get you close. Keeping your gun original has its pluses too.

Agreed. If a guy reads the Ackley books you will quickly realise just how many guns he blew up over the years. You will also find a lot of his published loads in those books are way higher powder and velocity than any load data that is pressure tested like Hodgdon. A lot of Ackleys extra performance came from exceeding normal pressure limits, more so than the change in case shape. On top of the poor feeding, these were the forerunner to the short mags that also don't feed well, the excess pressure levels many load AI to, they also suffer from lousy resale. All in all, there are far better options than to AI something.

except
 

The Arisakas 38/97 even Ackley couldn't manage to wreck them.

correction
 

38 +99 Arisaka

Ackley's manuals are a must read for sure, not positive they are still in print though. There was no love lost between P.O.Ackley and Rocky Gibbs by the sound of things. D.H.

I have a 22-250 AI and neither the targets or the gophers, know the difference... IF this target rifle where a regular old 22-250..... It would have been sold a dozen times over...As an AI ..not so much... most people look at you like you have 3 eyes when you talk about AI.... and resale. :(

we are not talking about every single ackley ever made, we are talking about 1 cartridge that worked, Fed, and shot very well for me. Chances are good it will feed and shoot well for another person.....FS
,

The ackley cartridges are good. Just be mindful of the fact that different actions will require a slight amount of “ tweeking” ,some more than others , that being the case you want to have someone that has experience with it .
I have had several ackleys and wildcats over the years , current shoot 257 ackley and 6mm ackley

I shoot the 25-06ai and it doesn’t have the dreaded and bemoaned feeding issues. The reason why I did it is I wanted to take on a new challenge of learning to fire form brass and tinker my way through the other ackley experiences good and bad. For all the guys saying you could just get the next rifle higher 25 Weatherby in my case, sure you could just like you could give up hunting and buy beef at the store. Sometimes it’s fun to tinker and learn new skills if you want an ackley just go get one and enjoy the learning curve life is to short for bland white bread everyday.

I know for sure having an ackley has taught me a lot about reloading and firearms modification and I have become far more skilled on the work bench because of it.

And this is why I got my one and only Ackley 280ai.

Never had any desire to own one, been 30+ yrs or so since I read it, still have the book. One constant thing I see on AI cartridges, is that damned few of them actually do anything much in the way of improving performance relative to the claims Ackley made. I wonder if the Epps improved cartridges were really any better? People love to tinker, for sure, cartridges are a prime example, we have Ackley, Epps, Howell, and I don't know how many others out there, some of the newer ones are based on stuff that was done 40-70 yrs ago, some older than that. Some of the newer powders have changed the scene enough, that "Ackley" performance could, conceivably, often be achieved in the existing cartridge.