HAHN is the maker mark of Charlie Hahn, a gunsmith known for his accurization work on revolvers, particularly the Uberti 1858 New Model Army Remington.

Charlie's work is characterized by several distinctive features:

Cylinder Modifications

• Reamed chambers to a precise size (4.56 in the example given)
• Faced off the front of the cylinder to match the new barrel made by Bobby Hoyt.

Barrel Improvements

• Installation of a new barrel with original-style gain twist rifling
• Gradual change in twist rate from breach to muzzle (1 in 18 inches at the muzzle)
• Consistent groove diameter of 4.53

Precision Work

• Perfectly dovetailed original sight
• Precise fitting of the loading lever catch
• Minimal cylinder gap, barely perceptible even when held up to light

Other Modifications

• Forcing cone at 5.5 degrees
• Chamber mouth slightly larger than ball diameter to allow for wear

Charlie Hahn's accurization process aims to improve the revolver's accuracy by addressing key areas that affect performance, such as consistent chamber sizing, improved barrel rifling, and precise fitting of components. These modifications are designed to enhance the firearm's overall accuracy and shooting characteristics compared to standard reproduction models.