257 Roberts Ackley Improved Rifle Cartridge

257 Roberts Ackley Improved
Rifle Cartridge

Abbreviated Name:  257 Rob Ack Imp



While there are several versions of .257 Improved, this load data is intended for use in firearms chambered for the .257 Roberts Ackley Improved (40° shoulder angle). The other prominent version is the .257 RCBS Improved, which features a 28° shoulder. If you are not certain about the chamber design in your rifle, we suggest consulting your gunsmith.

To fire-form brass for the .257 Ackley Improved, we suggest the following procedure:

  • Start with a standard .257 Roberts cases
  • Select a light load of relatively fast powder (IMR4895 is great) from the standard .257 Roberts data.
  • Seat the bullet well out into the rifling, so that it makes good contact with the lands when the cartridge is chambered. This holds the case head against the bolt face and eliminates case stretching in the web area, a cause of case head separation.
  • After fire-forming, follow load data for the .257 Roberts Ackley Improved.



Loaded for 257 Roberts Ackley Improved is Not offered at this time.




Chambered for 257 Roberts Ackley Improved is Not offered at this time.



257 Roberts Ackley Improved
HandLoading & Reloading Components:





AccuBond Bullet

  • 25 Caliber 110 Grain

Ballistic Tip Hunting Bullet

  • 25 Caliber 90 Grain
  • 25 Caliber 115 Grain

Ballistic Tip Varmint Bullet

  • 25 Caliber 85 Grain

CT Ballistic Silvertip Bullet

  • 25 Caliber 115 Grain

E-Tip Bullet (Lead Free)

  • 25 Caliber 100 Grain

Partition Bullet

  • 25 Caliber 100 Grain
  • 25 Caliber 115 Grain
  • 25 Caliber 120 Grain



Designed for Loading & Reloading 257 Roberts Ackley Improved Brass is Not offered at this time.