Bullet: 300 gr Barnes Originals  (Barnes)

Diameter: 0.458"

 

Powder: IMR 4227 (Improved Military Rifle)

Starting Powder: 38.5 gr

Max Powder: 41.5 gr

 

Primer: FED 210m

 

Case: HDY

Trim Length: 2.090"

 

Cartridge Overall Length: 2.510"

 

Starting Velocity: 1,935

Starting Pressure:  

Max Velocity: 2,094

Max Pressure:  

 

Crimp case mouth into top cannelure groove. *Do not use Barnes’ spitzer-shaped Original or spitzer-shaped TSX bullets in tubular magazines.
Barrel: 24" with 1:20" twist.

 

Source: https://www.barnesbullets.com/wp-content/uploads/2021/05/450Marlin.pdf