Artwork of paint and steel are equally at home in the MullerWorks shop.

How they are made

Each barrel’s production story starts with a piece of steel and how, through a careful analysis of the steel as it is drilled, reamed and rifled, Dan gains an understanding of its inherent characteristics and determines how to get these characteristics to work together in harmony. This careful attention ensures that the final barrel gives a consistently high caliber performance.

"You have to be able to adapt to what the steel is telling you at each stage of production. The ideal barrel is one that is forgiving -- you don't want it to be finicky with the bullets and powder you use. It has to shoot accurately with a broad range of loads," Dan says.

All MullerWorks button rifle barrels are made from 416R stainless steel. Right now, all drilling and reaming takes place at Rock Creek Barrels on Pratt & Whitney machines. Then each blank is inspected for three things:

  1. Straightness of the drilled hole;
  2. Quality of the ream; and
  3. Size of the ream.

Blanks that pass inspection are transferred to the MullerWorks shop. Once there, each blank is hand lapped to remove all tool marks and to prepare it for rifling. The lubricated blank is rifled on a sine bar rifler to the shooter's specifications.

During rifling, the hydraulic ram pressure is closely monitored by a pressure gauge. This ensures that a consistent pressure is maintained as the button travels through the entire length of the blank.

After inspection, the rifled blank is sent out to be heat treated. Heat treating ensures that the stresses that are put into the steel blank during the buttoning process are removed. Heat treated blanks are inspected upon return to the shop for sizing and any imperfections.

Contouring is done on a Romi CNC lathe, which allows for a precise and consistent barrel profile.

The final part of the production story is that each barrel is hand lapped by Dan. This allows him to bring out the best qualities that the barrel has to offer -- a finish that minimizes fouling and an internal taper that enables each and every bullet to travel through the barrel uniformly.