.257 Roberts AI Questions

[wolfhound11b]

Hi All,

Looking for some help with my .257AI and hope some of you folks out there can answer some of my questions.

First a little about the rifle:

I picked up the Improved Bob at a gun show and took to to my local smith for a once over. He said it looked great and it was built properly. Its a Mauser 98 Action with a 30 inch 1:10 Douglas varmint taper barrel with a brake. It has an 11 degree crown on the barrel and is in a laminate bench rest style of stock, its bedded and has a timney trigger. Sitting up on top is a Sigtron SIII 6-24x50 on Leupold mounts. I have shot the rifle and reloaded for the rifle and it shoots decent enough (.5 groups of 5 shots at 100).

So now to the questions:

1. I have a problem with brass. It seems to be hit and miss. Some brass is holding up very well and some is not. I was told that I should look for .257 Roberts brass and not the .257 +P because the +P brass can be too "rigid" to be fire formed properly. Has anyone else heard that?

2. I am looking for a good fire forming powder. The Nosler reloading manual says to use IMR 4895. I cant find any of that flavor of powder and have been on waiting lists for a while to no avail. I have Varget, H4831, VV-N540 and VV-N160. I would like to use Varget but I dont know it it is too fast of a powder to fire form with. Will any of those fit the bill?

3. Is there a die out there that can form the brass for me so that I can start the forming process and not put the brass through as much with the final fire forming to my chamber. I know there are hydraulic dies, but I was wondering if any one has seen a case forming and trim die for the 257 AI?

Thanks!

Sean

 

[CatShooter]

Been there and done it - I have this tee shirt.

I'll write you a PM in a little while and walk you through it.

 

[Clod-NC]

Hi Wolf,hi Cat,hi all

Sorry to sort of hijack your thread Wolf but I'll take the opportunity at the rebound 'cause I'll soon have the same problem fireforming the same brass as you,except in 6.5x57 imp 30°....And I don't know which powder to use,I read that regular pistol or shotgun powder in small quantities will do the trick,but,if Catshooter is willing to pm me or email me on the subject,I'd be definitely pleased and reassured. So thanks in advance if you do CAT...A nice week end and good shooting to all.

 

[jcampbellsmith]

Sean
When I had my 243 Ackley, I just developed a fire forming load and went shooting with it. Once I had formed brass I developed a fire formed brass load.
This sika stag fell to the fire forming load one evening.
https://dl.dropboxusercontent.com/u/12296998/Deer/Sika%20royal.jpg
Regards
JCS

 

[CatShooter]

Hi Wolf,hi Cat,hi all

Sorry to sort of hijack your thread Wolf but I'll take the opportunity at the rebound 'cause I'll soon have the same problem fireforming the same brass as you,except in 6.5x57 imp 30°....And I don't know which powder to use,I read that regular pistol or shotgun powder in small quantities will do the trick,but,if Catshooter is willing to pm me or email me on the subject,I'd be definitely pleased and reassured. So thanks in advance if you do CAT...A nice week end and good shooting to all.

Done...

 

[Ackman]

So now to the questions:

1. I was told that I should look for .257 Roberts brass and not the .257 +P because the +P brass can be too "rigid" to be fire formed properly. Has anyone else heard that?

2. I am looking for a good fire forming powder.

3. Is there a die out there that can form the brass for me so that I can start the forming process and not put the brass through as much with the final fire forming to my chamber. I know there are hydraulic dies, but I was wondering if any one has seen a case forming and trim die for the 257 AI?

Mine (257AI) uses a 28" K&P barrel, very smooth. Chamber is minimal with .286" nk, 0 freebore.

1) I have both .257 and +P brass. Hornady and Winchester. Haven't seen any difference, it all forms nicely.

2) My fireforming load was W760 powder and 85/87gr bullet. That power works really well in 22-250, 243, 6mm/257 sized cases.

3) You don't need a die to form AI brasss. Just work up an accurate load and shoot it....use fireform loads as you would use formed brass. I fireformed many hundreds of cases with bullets shooting mostly rockchucks. Fireform load was an 87TNT or 85BT at from 3635 to 3774 depending on which bullet.

 

[ar15topgun]

Winchester brass, IMR4064 powder, LR primer and an 85 to 100 gr. bullet. Load and shoot. I have never lost a single piece of brass fire forming a 257AI and I started shooting one in the early 80's.

 

[CatShooter]

"...and I started shooting one in the early 80's."

Nothing before 2008 counts anymore...

... Obama decreed it!

 

[wolfhound11b]

Hey Guys,

Thanks for the info. Sorry it took so long to get back on here. I had an anniversary (10th) the day after the post and I am a 100% disabled vet and the things that hurt were really hurting so I was pretty much off the internet for a week. But no excuses. Thanks again for the information I am going to use what info I gained from the posting and some from a private message I received on the topic. I am reloading some brass and will post some results of what I have come up with. I absolutely love my 257 Roberts Ackley and cant wait to try some of your ideas.

Here are a couple more questions:

Has anyone out there tried Norma Powders in the 257 Roberts Ackley Improved. I picked up some Norma 204 and MRP a while back for my wifes 6mm Rem and 30-06. I would like to try it in mine but I cant find load data for it anywhere.

Can I use load data for the standard 257 Roberts and adjust as needed? If so is there a starting point for example, 10% more than the standard load data?

Thanks again!

Sean

 

[cdparker]

Sean--Get a look at Ackley Vol. 1 There is data on both the .257 and the AI. N203B is very close to Re15 and N204 is similar to 4350/Re19. That should give you a place to start. If I were doing it when fireforming, I would seat my bullets into the rifling so that the case is held against the bolt face. The firing pin can push the case forward a wee and when the case expands, you can get a false base to shoulder dimension. Ackley used 4350 with the heavier bullets.
HTH-Craig

 

[gotcha]

Hi Sean! DON'T trim your AI brass until AFTER fireforming. The .257 brass will actually shrink in length after fireforming. The +P stuff is a little thicker in order to handle the higher pressure loads. A properly formed AI chamber allows for an approx. .003" crush fit at the neck/shoulder junction. If you chamber a .257 Rbts case in your .257AI chamber You'll see a bright mark on your brass @ the neck shoulder confirming this "crush" fit. No need to jam bullets into the lands! P.O. Ackley designed the chamber to readily fireform .257 Rbts. ammo. So, full power .257Rbts. loads are fine for fireforming. I use IMR 4064 & get tiny fireforming groups. (Krieger BBL, Berger 87 gr match/varmint) Its a Great cartridge. Need more info? Drop me a PM. , Dale

 

[Ratchet]

Hi Sean! DON'T trim your AI brass until AFTER fireforming. The .257 brass will actually shrink in length after fireforming. The +P stuff is a little thicker in order to handle the higher pressure loads. A properly formed AI chamber allows for an approx. .003" crush fit at the neck/shoulder junction. If you chamber a .257 Rbts case in your .257AI chamber You'll see a bright mark on your brass @ the neck shoulder confirming this "crush" fit. No need to jam bullets into the lands! P.O. Ackley designed the chamber to readily fireform .257 Rbts. ammo. So, full power .257Rbts. loads are fine for fireforming. I use IMR 4064 & get tiny fireforming groups. (Krieger BBL, Berger 87 gr match/varmint) Its a Great cartridge. Need more info? Drop me a PM. , Dale

We

 

[Barlow]

I use 39gr, 3031, 75gr Hornady hp's Remington brass to fire form. Sub moa accurate, no case loss. It generally takes two firings to get complete fill out no matter how I did it, but the first bang is 98%. Ackley Improved cartridge's are made to use standard factory ammo to form from. The only caveat would be if you don't have any resistance when closing the bolt. I have had one for thirty plus years and never had a problem. I currently use RL17 in this rifle with excellent results. Barlow

 

[jplahr]

Its not hard to fireform for any Ackley. Start with new brass doesn't matter what brand. Use any powder that will work in a .257 Roberts I use a mid load. Seat the bullets so they are hard it the lands and put a very lite coat of oil on the case and shoot. The oil will let the case slid in the chamber and the case will stretch from the front and will form perfect. I have done this with 6PPC. .250 Ackley, 25-06 Ackley, 257 Ackley and 280 Ackley and never had a problem.
Jerry

 

[Tommie]

I’m guessing the OP got it figured out by now.

 

[Clark]

My brother, two friends, and I chambered (4) 257RAI Mausers with Lothar Walther light varmint barrels 17 years ago.

The first one was mine, and I used a new piece of Winchester 257 Roberts brass as the go gauge.

Mistake.
That allowed the firing pin to push the Roberts brass into the sharp neck base ring of the Ackley chamber and thus move the case forward. When the case fired, it gripped the chamber walls. When pressure built, the case stretched and cracked.

I should have made the headspace 0.004" short of that. Closing the bolt would have then pressed the brass 0.004" into the sharp neck. The firing pin would no longer be able to push the case forward.

But I have not set the barrel back yet, in 17 years.
I have to fire form the brass in an extra step.
Now what I do with that rifle is load 10 gr of any pistol powder in a 257R case, cover with cream of wheat, fireform, and it forms a 50% Ackley shoulder. That stands up to the firing pin push on the next firing with a bullet and a full charge of rifle powder.

The reason I have not changed the rifle is that it shoots so well. The rifle has shot a number of 1/2" 5 shot groups at 100 yards with 75 gr Vmax.