New Thompson 1927 A1

alanint · 08-14-2012, 08:58 AM

Although I would never add this to a "how too" manual, I have solved fit issues with West Hurley and Kahr made drums by taking the "ribs" built onto the side of the drum, (which are meant to slide into the grooves in the gun's receiver) and pressed them flatter in a vice. If you compare a Kahr or West Hurley drum to an original Colt or Seymour offering, you will see that these ribs are really poorly formed on the later drums. They are thicker and rounder and not a crisp fold as the originals are. Colt and Seymour show a very neatly folded and pressed rib, which is uniform and flat across its length. The WH and Kahr drums show a weakly rounded pressing, which is invariably thicker than the groove channel in the gun's receiver. Many people make the mistake of grinding on the gun's channels to achieve a fit. By taking the drum's pressed ribs and laying them flat into a crisp edged vice, you can squeeze this poorly rounded rib into a flatter, thinner profile, which should then fit the gun with minor filing and fitting. I would rather screw up a $100 drum than the gun's receiver.

08-14-2012, 08:58 AM	#11
alanint User Join Date: Mar 2008 Location: Marco Island, Florida Posts: 4,867 Thanks: 1,685 Thanked 1,917 Times in 1,193 Posts	Although I would never add this to a "how too" manual, I have solved fit issues with West Hurley and Kahr made drums by taking the "ribs" built onto the side of the drum, (which are meant to slide into the grooves in the gun's receiver) and pressed them flatter in a vice. If you compare a Kahr or West Hurley drum to an original Colt or Seymour offering, you will see that these ribs are really poorly formed on the later drums. They are thicker and rounder and not a crisp fold as the originals are. Colt and Seymour show a very neatly folded and pressed rib, which is uniform and flat across its length. The WH and Kahr drums show a weakly rounded pressing, which is invariably thicker than the groove channel in the gun's receiver. Many people make the mistake of grinding on the gun's channels to achieve a fit. By taking the drum's pressed ribs and laying them flat into a crisp edged vice, you can squeeze this poorly rounded rib into a flatter, thinner profile, which should then fit the gun with minor filing and fitting. I would rather screw up a $100 drum than the gun's receiver.