Why AI?

[BoilerUP]

Not sure where to put this, posted here because I figure it'll get more views:

Why do so many folks prefer the Ackley Improved version of a given chambering?

I'm still learning a lot about reloading & Savage rifles and what not, but I've generally gathered AI gives you a little more velocity. Isn't there a fair bit of work involved (fire-forming brass, special-order reloading dies, etc) with having an AI for another 100-200fps velocity?

Are there any other benefits?

[hcpyro13]

The extra work isn't that bad, and I seem to be getting better brass life since the brass "flows" less. Not to mention having something a little more unique then many others you meet at the range! I started out with a straight 260 and it evolved into a 260 ai due to a flaw in the chamber. I love it, but then again I'm a little strange since a 300 weatherby is my favorite all purpose round. (it did a great job on woodchucks last year!)

-Jake

[laportecharlie]

I have done two of them: 280AI and 223AI. Besides the novelty of it and the possibly extended brass life they really aren't worth it. The Remington 7MM SAUM exactly duplicates the ballistics of the 280AI with a factory (albeit nearly extinct) round. When pressure is kept to a reasonable level the velocity gain of the 223AI hardly justifies the expense. Fred at SSS told me the 223AI wasn't worth it but I didn't listen. I had fun building them and enjoy shooting them but I probably wouldn't do it over.
Charlie

[tammons]

I have never owned an AI but you get more powder and a bit better performance.
Some cartridges like the 223 very little and others a good bit.
Helps with brass flow.

Part of the AI design parameters were to be able to shoot the factory round in an AI chamber.
There was even a 458 win mag AI, and the 458 WM is a straight walled case.

Personally after owning a 338-284 wildcat and a 30mm BR, I decided that fire forming and turning
brass was not for me when a lot of factory cartridges will do the same thing.

Still some people love it.

[tiny68]

Novelty... first and for most. A little speed is sometimes ok. I found with my 6mm Rem Ackley, that the 107 Sierra Match King doesn't prefer to my pushed at the max speeds capable with this round. The great advantage to the Ackley's in my opinion is the minimum stretching that occurs compare to the tapered parent. With my 22-250, I have to full length size with each firing. With my 22-250AI I only full length size once every 3-4 firings (only will bolt has significant resistant to close). I see the same trend in my 6mm Rem vs 6mm Rem AI. Cost vs. performance vs. novelty is all part of the game. Shoot and enjoy, Tim

[BrentWin]

Why AI?

257 Weatherby speed out of a 25-06 with about 12-14 grains less powder.

[rsbhunter]

I know that it may not be worth it to change from non AI to AI , but , if starting from scratch, and building a new rifle cartridge barrel, would any of you start with an Ackley? The brass is the same cost, dies might be a little higher, but the life of the brass and improved ballistics would be aa plus right? This is a question, as i am looking at possibly building a 243AI and a 257 Roberts AI, and will reconsider if everyone thinks the gains aren't worth it...Thanks for any thoughts about this....rsbhunter

[Eric in NC]

The gains depend on the cartridge. I think it is well worth it to go with a 22-250AI or 250 Savage AI as the case design of the original (lots of taper) makes them get quite a gain when you blow them out.

Now a 308AI? - really wouldn't see the point.

[BrentWin]

I know that it may not be worth it to change from non AI to AI , but , if starting from scratch, and building a new rifle cartridge barrel, would any of you start with an Ackley? The brass is the same cost, dies might be a little higher, but the life of the brass and improved ballistics would be aa plus right? This is a question, as i am looking at possibly building a 243AI and a 257 Roberts AI, and will reconsider if everyone thinks the gains aren't worth it...Thanks for any thoughts about this....rsbhunter


For both of those cartridges the gains are very worth while. I would chamber AI from the start, why pay for chambering twice?

[dcloco]

I have done two of them: 280AI and 223AI. Besides the novelty of it and the possibly extended brass life they really aren't worth it. The Remington 7MM SAUM exactly duplicates the ballistics of the 280AI with a factory (albeit nearly extinct) round. When pressure is kept to a reasonable level the velocity gain of the 223AI hardly justifies the expense. Fred at SSS told me the 223AI wasn't worth it but I didn't listen. I had fun building them and enjoy shooting them but I probably wouldn't do it over.
Charlie


Interesting. The 223 Ai's that I own, all provide 3580-3600 fps with 50/52/53/55 gr bullets. ....and I am NOT using N133 as others have said to try.

69 gr Nosler or Sierra HPBT's at 3300 and 75 gr AMax at 3150....all out of 26" barrels. What is not to like about a 223 Ai?

[gotcha]

Boiler up, Your question got me to thinking & I have two AI's (6mm rem. & 257 rbts) I love both ! They gave me the xtra velocity I was looking for. They do not require special dies. I use the Redding body die, standard lee collet die & standard seaters for both. The brass lasts longer and rarely needs trimming. For me the fun was building something different and the learning process that went along with it. Not all AI's give worthwhile improvements in velocity. A little snooping around on the net will bear this out. Fire forming is easy. You can use slightly less than max loads and do fire forming & load development at the same time. Or use the COW method if you prefer.(much more time consuming) I use 80 to87gr bullets in both & get closer to 400fps xtra spd. out of the .257. On the other hand the wide range of cartridge choices available today allow for some pretty awesome off the shelf picks. My next rifle won't be an AI. But, down the road ------- That 250 AI looks awfully interesting !! Have fun which ever way you go, that's the whole point ! Dale

[nova1194]

There isnt really extra work with the ai, my 223ai and 22-250ai are very accurate while fireforming brass, so I just load up a hundred factory cases, go out and spend a nice day with the prarie dogs and then I have 100 ai cases to do some testing with, so its not like you are just wearing out your rifle to make brass, and like the others have said, with some cases the performance gain may be modest, but the increase in brass life means less work at the bench.
Every barrel is different, my first 223 ai is a factory 9 twist stainless fluted barrel and after it was rechambered it did not gain as much as I thought it would, my second was a 14 twist adams and bennet barrel and it picked up over 50fps more than the factory tube.
Right now I have a 308 barrel sitting around and I am thinking seriously about a 30-06 ai to replace my 300 win mag, I know the 06ai will be a little slower but I will get away from that dang belt and it will be nice not to have to trim a case every time I fire it.

Mike

[epmn]

All I shoot is the 75 Amax. The extra 100fps in a .223AI and 200fps in a 22-250AI helps them stabilize better in a 1/9 barrel as well as extra distance when out prairie dog shooting. Since I have the reamers and the lathe it isn't costing me anything but setup time at this point to do a chamber.

An example of the improvement is a light weight barrel I re-chambered for a friend's walking coyote gun. It was a 1/9 that shot about an inch and a half with the 75s in .223. Since the change he has had groups as low as half an inch. It could have been the stellar chamber job but I'm willing to go with the increased speed as the improvement. In his case he already had another .223AI so once again it didn't cost him much for the change.

Personally I have two .223AIs and two 22-250AIs.

epmn

[durango]

How about a .260?--starting from scratch with a new quality barrel. A couple comments in this thread are confusing to me--It was said that a .243 is a good candidate but another says that the .308 is not worth it. Same parent case family--why the difference? Kinda like the .223-seems that I've read that the .223 design was pretty much a miniaturized 30-06 case. Fred says no on the .223 and others here are touting the 25-06 and 30-06 as good choices. I guess what I'm trying to figure out is--what are the parameters that make one cartridge a good candidate and another one not so good? Steve

[Eric in NC]

223 is not a mini 30-06 - 222 is close to a mini 30-06.

All depends on your opinion as to "how much" improvement is required to make it worthwhile. And the improvement is not always equal across the bore diameter of various case designs (people tend to think the 25-06AI is a good improvement and the 30-06AI isn't much of one).

In general, cartridges that use slower powder (25-06) or have more taper (Mauser or 250 Savage based cartridges) will see more improvement. As the bore for a given cartridge case gets bigger, appropriate powders generally get faster, and the difference gets smaller - a 6mmRem AI or 257 Roberts AI = well worth while. A 9.3x57 AI (same case necked up) = not so worthwhile in my opinion. Same goes for the 308 family (no reason in the world to make a 358 Win AI, but folks see good improvement in the 243 AI).

Of course sometimes you might want to do it for improved headspace control (I love my 375-06AI).

[laportecharlie]

I think when the dust settles, what it comes down to is this: While they are fun to build, there is almost always a factory round that will do pretty much the same thing. But that is no reason not to try one!
Charlie

[helotaxi]

there is almost always a factory round that will do pretty much the same thing.
That's the case with almost every wildcat out there. That said I've considered swapping two of my bolt guns over to AI versions simply because I hate trimming brass. THAT is something that few factory rounds can do.

[laportecharlie]

So true
C

[rsbhunter]

Well, you all have convinced me to try at least one in the AI version....now i wished i had bought 2 long actions, and 1 short....can the 257 Roberts be built on a short action, or would i lose (by deep seating) what i gain by going the AI route? Thanks, this site really is a help....i know at least 1 will be the 243AI, the long action will most likely be the 6.5x284....and the 2nd short ?????? rsbhunter

[helotaxi]

Well, you all have convinced me to try at least one in the AI version....now i wished i had bought 2 long actions, and 1 short....can the 257 Roberts be built on a short action, or would i lose (by deep seating) what i gain by going the AI route? Thanks, this site really is a help....i know at least 1 will be the 243AI, the long action will most likely be the 6.5x284....and the 2nd short ?????? rsbhunter
If you look in the Sierra manual in the .257 AI data section, their test rifle is a Model 12. A short action. I've played around with how long you can run COALs in Savage short actions. The centerfeed magazine is slightly over 3" Loading to 2.95" shouldn't be an issue with feeding. You're not going to lose anything building on a short action.