Home Forums Reloading Big Game Rifles Fireforming .257 Roberts AI

I recently ordered a McGowen barrel and will be trying out the Ackley Improved version of the .257 Roberts and need some good advise on fireforming the brass. I have reloaded for several years, just never loaded for an Ackley cartridge.

Buy some 257 Roberts brass or loaded cartridges and go shooting. You will come home with 257 AI brass. That's what is neat about the Ackley Improved design.

Books will tell you that you need to seat the bullet into the lands when fire forming, but I haven't found that to be true. There will be a crush fit on a standard case, and then you just let one rip. Voila...AI'd case.

I always trim my newly formed case after the first resizing to square up the neck. Other than that, same old same old.

I was delighted to find that the Roberts rounds that I loaded to form brass was very accurate and velocity was good. I have used a variety of recipes over the years, often using the load Nosler noted as their most accurate in their Roberts data.
I have shot onlu a couple boxes of factory Roberts ammo, again accurate with good velocity. Good enough to hunt with if it became necessary.

Ditto on Fishdog52, I have made up 2 of them, 1 for each son as there first center fire rifles, never bought any other, they have killed WT and Mullies, Elk and BLACK Bear, using 115 NPT's, I do the reloading and they have not wanted to go to 100gr PT for deer. All were 1 shot kills DRT except the bears, they went less then 50 yds. I fired formed all brass just shooting Win 257 Roberts+Ps

Rattl3:
The Nosler #6 manual, pg 196 has simple instructions for fire forming the .257 Imp. (40 deg. shoulder). Tho I haven't used nor shot my .257 Imp. in years, I fireformed cases using basically the same info in Nosler #5. Didn't have any problems.
Good luck, I think it's a very nice cartridge.
Bear in Fairbanks

Thank you all who replied. I am looking forward to getting my barrel in a few weeks. I guess I need to start looking for some brass and dies. Thanks again.

Have had 2 257 Roberts AI, my latest was chambered correct.

My first was not chambered correctly in a push feed Ruger Tang safety. A real pain to fire form brass, had to use a false shoulder to hold case back on fire forming.

If its chambered correctly bolt will be snug on closure on a Std
Roberts case.

Yep. Great way to enjoy some carefree shooting!

IIRC mine shot sub-MOA w/ 36 gr RL15 under 100s smashed right into the lands.

Sometimes if you dont have a strong enough load the cases wont fireform completly. Some guys will say to use havy bullets and load them up close to max. But I just tried using some 87 grainers with a medium dose of rather fast powder, (I think it was 3031) and it worked great. The faster, peppy powder formed the cases perfectly. It is a good way to fireform on the cheap..

The 257AI is a fabulous round. Mine equals 25-06 velocities with much less powder.

There are two primary problems encountered when fire-forming AI rounds:

1) The gunsmith just cut an AI chamber in a factory barrel, without setting it back enough to get a crush-fit on factory brass.

2) Trying to fire-form previously fired brass. This eliminates the slightly rounded transition from the neck to the shoulder that crushes in new brass.

In either instance you'll get misfires and "short-formed" or stretched cases, sometimes even separations.

Different brands of brass also often slightly different dimensions. If you tell a competent gunsmith what brand of brass you'll be using, or give him a few cases, he'll be able to provide that nice crush-fit.

I've had good luck with the 25-06AI and the 280AI fireforming with the blank cream of wheat and Unique powder method. Start around 10 grains of powder and work up till you get the properly formed case. You can get about 95-98% formation with this with no need to fire a bullet. I built a PVC pipe trap to shoot into indoors to catch all the filler. Very quiet too, sounds like a firework mortar launched from the tube.