Question about Fire Forming 257 bobs into 257 AI

watersfam

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May 17, 2021
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Carlsbad, NM
So I am a newby at fire forming. For any out there that fire form cartridges...

I picked up a 257 AI by sheer accident in an auction. Rifle was obviously a customized left-hand hunting rifle with a Savage 110C action when I bought it. After I received it my FFL dealer and I took it out to the range and fired a new Hornady 257 Roberts round through it. We examined the spent cartridge and notice it fire formed into an AI round.

He indicated that I needed to go out and fire form about 100 257 Bob shells and reload them for the AI with the hunting bullet of my choice. I took five boxes of cartridges out this weekend to form. of the 40 rounds I shot, one cracked at the neck as was expected, but two ruptured near the base (see photo).

Half of these were reloads and may have been too hot. The three ruptured shells (bottom 3) were all reloads. The factory loads were "silver tips" and appeared to work just fine (see #2 from top) I had to stop at two boxes because rifle was getting hot and because each time the shell ruptured at the base, the bolt could not extract the shell and I had to remove and clean the extractor and ramrod the shell out.

Are the reloads too hot or is the a problem with my headspace being to large? I don't want to ruin this nice rifle.

257 Roberts, AI and fire formed shells with damage.jpg
 

MagnumManiac

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Feb 25, 2008
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3,555
Looks like brittle brass to me.
It’s never a good idea to use brass fired in the parent chamber to then try to fireform to the AI.
I did the same in both my 22-250AI and 257AI when I was green.
Nowadays, I only ever use NEW brass and I anneal it before I attempt to fireform them.
Some brass should be avoided in my experience. Norma, Federal & early Nosler brass do not like fire forming. Have had the best luck fireforming Remington brass with zero failures if annealed first.
I only have 3 cartridges I fireform now, 22-250AI, 375 Weatherby & 338-416 Rigby Improved 45°.
I use the COW method to close, then fireform with a stout load for hunting.
I use Universal powder to fireform, about 1/3rd load of a normal powder gets it done.

Cheers.
 

watersfam

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May 17, 2021
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Location
Carlsbad, NM
Looks like brittle brass to me.
It’s never a good idea to use brass fired in the parent chamber to then try to fireform to the AI.
I did the same in both my 22-250AI and 257AI when I was green.
Nowadays, I only ever use NEW brass and I anneal it before I attempt to fireform them.
Some brass should be avoided in my experience. Norma, Federal & early Nosler brass do not like fire forming. Have had the best luck fireforming Remington brass with zero failures if annealed first.
I only have 3 cartridges I fireform now, 22-250AI, 375 Weatherby & 338-416 Rigby Improved 45°.
I use the COW method to close, then fireform with a stout load for hunting.
I use Universal powder to fireform, about 1/3rd load of a normal powder gets it done.

Cheers.
Thank you

The rounds I used were old factory Win. Super-speed (mistakenly id'd as reloads) and factory Win. Silvertips. My father who has reloaded since the 60's and still reloads quite a bit looked at the rounds that I was shooting and he is certain that the ones I thought were reloads were actually factory loads. I had one random Remington thrown into a single box, which caused me to think all of those boxes were reloads. Those are actually all 87 grain short Win. Super-speed soft points. These are considerably shorter bullets than the 100 gr. silver tips, which did not have any problems, so maybe they aren't setting deep enough and it may be a headspace issue.

My dad also suggested using new .257 Bob brass or find some pre-formed .257 AI brass. I have not seen either on the internet and finding them here in SE New Mexico will be impossible. Only thing that is sold here is Brand new Hornady at $75 a box. Not sure my wallet can take shooting those to fire form them.

My father thought he could pull the bullets and reduce the charge. While he has never dabbled in wildcat rounds, he has a good library of old books on reloading. He has an old book that mentions using a reduced charge, then cotton, then something like cream-of-wheat, followed by paraffin to fire form parent cartridges into AI cartridges. Is this the COW method you were talking about?
 

MagnumManiac

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Yes, COW method is a fast pistol/shotgun powder at about 1/3rd of a normal load, then COW on top and a twist of TP.
You may need to use a false shoulder if your NEW brass does not close with some resistance on the bolt.
I used to use a 6.5 expander and expand all the necks in the 257 die, then put the 257 expander back in and create a false shoulder by gradually necking down until a case just allowed the bolt to close with some resistance. Even though my chamber had .005” negative headspace, I would occasionally get head separations. It wasn’t caused by the die, and I still got a few every now and then. My Dad owns that rifle now.
Those splits in your brass are not from excessive headspace, maybe the chamber is on the large side near the web...only way to know is measuring unfired brass against fired brass.
Hope this helps you get some brass formed without issue.

Cheers.
 

FEENIX

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Great Falls, MT
My dad also suggested using new .257 Bob brass or find some pre-formed .257 AI brass. I have not seen either on the internet and finding them here in SE New Mexico will be impossible. Only thing that is sold here is Brand new Hornady at $75 a box. Not sure my wallet can take shooting those to fire form them.

My father thought he could pull the bullets and reduce the charge. While he has never dabbled in wildcat rounds, he has a good library of old books on reloading. He has an old book that mentions using a reduced charge, then cotton, then something like cream-of-wheat, followed by paraffin to fire form parent cartridges into AI cartridges. Is this the COW method you were talking about?
The choice is yours to make if you want to isolate if the brass is the issue. Ackley's improved cartridges were designed to fire factory ammo/load and should not need to do the COW method.
 
Last edited:

Wild_Bill

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Load new brass or fire factory ammo. You can safely fire max loads for the parent case in an Ackley chamber. You don't need to down load them and I wouldn't reccomend that. You also do not need to fireform all of your brass. Just settle on a fireforming load or factory buy 100 rounds or get 100 cases and shoot that load while hunting until it's all formed then once you have formed brass work up an ankle loaf. The headspace should be.004" shorter than the basic case and you should be able to feel the case seating to the shoulder while chambering. If the cases are not touching the shoulder you may have excessive heaspace and that can be easily fixed on a savage. Also measure the case head on fired brass to make sure the chamber is not oversize.
I think the biggest issue is old WW brass as most WW brass was made undersized on the base to ensure extraction, that and being extrely old is likley to have caused it to become brittle and split.
 

watersfam

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May 17, 2021
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Carlsbad, NM
Load new brass or fire factory ammo. You can safely fire max loads for the parent case in an Ackley chamber. You don't need to down load them and I wouldn't reccomend that. You also do not need to fireform all of your brass. Just settle on a fireforming load or factory buy 100 rounds or get 100 cases and shoot that load while hunting until it's all formed then once you have formed brass work up an ankle loaf. The headspace should be.004" shorter than the basic case and you should be able to feel the case seating to the shoulder while chambering. If the cases are not touching the shoulder you may have excessive heaspace and that can be easily fixed on a savage. Also measure the case head on fired brass to make sure the chamber is not oversize.
I think the biggest issue is old WW brass as most WW brass was made undersized on the base to ensure extraction, that and being extrely old is likley to have caused it to become brittle and split.
Thanks for the info. Love the rifle and the action. Will measure the case head on the spents and see if it is sized correctly. I didn't know that the WW's were smaller at base for extraction. Remingtons were suggested above and I found some fairly recent core-lokt's at local pawn shop. I will try those. With respect to firing the parent loads in the AI, is the accuracy or speed affected? I haven't tested the ones I was fire forming with respect to accuracy, just been shooting at a hill without a scope. Scope and rings are on order.
 

big johnson

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E. Wenatchee, WA. 98802
I've seen several 257 ai that were cambered to long in the throat and factory ammo won't even fire, the whole case moves forward when the firing pin strikes the primer, not good. we pulled the bullets and moved them into the lands then they worked fine. Remember that all reamers are not exactly the same and can vary several thousands. New brass will work the best .If you can find the 257 roberts +p ammo it's a little hotter and works better. You can use 7mm mauser brass and neck it down to 257 or 6mm rem. and neck it up. 6mm has been showing up at several suppliers. Good luck It's a great cartridge.
 

grry10

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Aug 3, 2011
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West Central Wisconsin
I use the COW method to fire form my 257 Ackley and have yet to lose a case. If it is used 257 Roberts brass I anneal first. New brass I skip this step. Step 1, run brass through 257 AI sizing die. Step 2, prime with magnum large pistol primers. Step 3, charged with 14 grains of Bullseye pistol powder. Step 4, top with Cream of Wheat to the base of the neck. I use a Lee hand measure for this step. Step 5, poke 1/4 of a sheet of toilet paper into the neck to hold everything in. Step 6, go outside, chamber, and fire each round to blow out the case. The cases come out formed with a slight rounding at the shoulder angle, but the cases have the capacity of the Ackley and you are ready to start developing your test loads. The sharp shoulder angles will form the first time you fire them using your test loads. For me, the COW method saves on brass, powder, bullets, and barrel live. I use it in .257 Ackley, 6.5-06 Ackley, and 338-06 Ackley (6.5 and 338 require extra depending on parent cartridge used.
 

arch408

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Dec 6, 2012
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Ackley designed his improved so that regular ammo would have a crush fit when it is chambered. The headspace was decreased .0001 inch to insure not having excessive when firing factory ammo.This was accomplished by using the “go” gauge for the “no go” setting. If you did not feel resistance when you chambered regular ammo, then you have excessive headspace. Have your rifle by a gunsmith that is familiar with Ackley improved cartridges. Or buy or borrow some .257 Robert’s headspace gauges. You will confirm the headspace problem if you can completely close the bolt on the “go” gauge.
 
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