257 Roberts Ackley Improved

[ScreaminEagle]

Just wondered if anyone here has played with one before. I plan on fireforming my brass by loading up some mild 257bob loads and just punching some paper. The COW method seems like a lot of screwing around to me. Plus I have lots of old bullets to plink with. I have lots of Nosler 100gr BT's and 110gr AB's for final load development. Also gonna try IMR 4350 and H414.

Anything special I should know about AI's?
Steve

 

[SJB358]

Nothing really about the AI Steve, but for me, I kinda think I would lean on the COW method, as I wouldn't wanna run bullets down the barrel of my new custom rifle, just to save it some life. If you don't mind that part of it, I can't see anything wrong with it. I know JD use's 280 loads to fireform his, but I don't think he shoots in near the volume you might shoot a 257 Ackley..

 

[nvbroncrider]

IMR-4895 is another good powder. I fire formed all of my 338 cases with a mild load went on hodgdons site and found something in the 50k range and seated the bullets really long and jammed them in the lands. I had barrel break in to do anyways so it didn't bother me any. If yours is custom throated you may have to use a heavy long bullet to fireform.

 

[JD338]

Steve,

My experience with the AI is only with the 280 AL but....

When fire forming AI loads, use a MAX load with the parent round. This is the starting load for the AI version.

A properly chambered AI will have a hint of a crush fit with virgin brass of the parent round. This will give you the head space you need so you do not need to jam the bullet into the lands.
You also do not need to do the COW method.

Good luck with the 257 AI. It is one very cool round.

JD338

 

[Oldtrader3]

From my experience with the plain ole .257 Roberts, IMR4064 works for 85 grain, IMR4350 for 100 and 110 grain bullets. I am also working with Hodgdon, Hybred 100V and the 110 AB bullet.

 

[ScreaminEagle]

Thanks for all the info guys. I am starting to get very excited about starting load development on an AI.
Steve

 

[ScreaminEagle]

Another question: Pac-nor website shows that they chamber for 257 roberts ackley and 257 ackley. Whats the difference?

 

[nvbroncrider]

Is it the 257 Roberts Improved and the 257 Roberts Ackley Improved? The Improved was a wildcat that was standardized by RCBS and the shoulder was blown out to 28* versus the Ackley which is blown out to 40*. Hornady has data for the RCBS version while Nosler shows Ackley data.

 

[ScreaminEagle]

Is it the 257 Roberts Improved and the 257 Roberts Ackley Improved? The Improved was a wildcat that was standardized by RCBS and the shoulder was blown out to 28* versus the Ackley which is blown out to 40*. Hornady has data for the RCBS version while Nosler shows Ackley data.

One says 257 ackley .284 neck, and the other is 257 Roberts Ackley Improved .284 neck

 

[efw]

When fire forming AI loads, use a MAX load with the parent round. This is the starting load for the AI version.

A properly chambered AI will have a hint of a crush fit with virgin brass of the parent round. This will give you the head space you need so you do not need to jam the bullet into the lands.
You also do not need to do the COW method.

As usual, Jim is spot-on.

The barrel life of a 257AI is such that fireforming won't be an issue there. Besides, the COW method seems to me to be based upon the assumption that one just blows through fireforming loads to have formed cases.

My cheapo-barreled 257 AI shoots fireforming loads (48 gr H380 & 75 gr Horns, or 43 gr RL15 & 100s) are UBBER accurate so I used em for summertime recyclable-blasting. Got great practice with em, a good feel for the rifle, and perfectly sharp shoulders. I also capped some 'chucks, and a couple coyotes. Coulda done in some deer or antelope, too.

Here is a group I shot at 200 yds while out w/ JD338. It has approx 1300 rounds through it; this is my "go to" load of 100 gr Interlock & IMR-4350 @ 3250 fps:

Moly'd 87 gr TNTs & RL-15 @ 100 yds:

I love the cartridge!

 

[ScreaminEagle]

EFW, that looks like great results. I figuered I'd come up with a fireforming load and blast at some chuck this summer.
Steve

 

[FOTIS]

EFW, those look great.

Some nice shooting right there!

 

[DrMike]

Enviable, Eric. Excellent shooting.

 

[ScreaminEagle]

Do you guys know if I can use the standard seater die when load the AI?

 

[Oldtrader3]

Sure, just back it off until the shoulders just touch the shoulder base in the seating die.