257 Roberts Ackley Improved
Rifle Cartridge

Abbreviated Name:  257 Rob Ack Imp

 
 

TECHNICAL INFORMATION:

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.
 

 

NOSLER AMMUNITION

Loaded for 257 Roberts Ackley Improved

Not offered at this time

 

 

NOSLER RIFLES

Chambered for 257 Roberts Ackley Improved

Not offered at this time

 

 

257 Roberts Ackley Improved
Loading & Reloading Components:

257 Roberts ACK IMP

 

 

NOSLER BULLETS 

Designed for Loading & Reloading 257 Roberts Ackley Improved

 
 

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 85 Grain
  • 25 Caliber 115 Grain

E-Tip Bullet

  • 25 Caliber 100 Grain

Partition Bullet

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

 

NOSLER BRASS

Designed for Loading & Reloading 257 Roberts Ackley Improved Brass

Not offered at this time

 

 

Available Cartridge Information:

 

RIFLE CARTRIDGES

 

35 Caliber / .358” Diameter

9.3mm Caliber / .366” Diameter

375 Caliber / .375” Diameter

416 Caliber / .416” Diameter

44 Caliber / .429” Diameter

45 Caliber / .458” Diameter

458 Caliber / .458” Diameter

 

 

HANDGUN CARTRIDGES

 

9mm Caliber / .355” Diameter

38 Caliber / .357” Diameter

10MM Caliber / .400” Diameter

41 Caliber / .410” Diameter

44 Caliber / .429” Diameter

45 Caliber / .451” Diameter