Kahr Arms CW45 Repair

A customer showed up at my shop with a Kahr CW45 all locked up, slide stop pin in hand, with a spent cartridge in the chamber. After tapping on it with a wooden mallet while working the slide I managed to get the pin back in and eject the cartridge. During take down the problem was shown to me by the customer. The slide stop spring screw was loose. He had tightened it several times when the pin was working out.

On further examination I found the plastic hole that the #2-56 machine thread screw was supposed After a glue-in method failed and realizing the expense of a full replacement, this was the best alternative. to nest in was stripped out. A call to Kahr’s service department revealed that their five year warranty covers the original customer only. A determination as to whether the damage was a factory defect could not be made over the phone and had to be examined by a factory representative.

The usual fix was a frame replacement at a cost of $250.00 plus $65.00 for one hour of labor. I decided to pursue an alternative fix for my customer. Reinforced Fastener Normal engineering practice would be to reinforce an area where a fastener is to be place under stress during use. In this case, that would be when a .45 ACP cartridge goes "bang" and drives the barrel and slide back against a pin held in plastic. The shock is transmitted to the screw via the pin to the spring and washer.

The spring is wound counter clockwise around the screw so a hit by the pin on the spring and the movement of the tail upwards at the last shot tends to loosen the screw. A quick Google search produced a number of people looking for a solution to the same problem. I first tried a Super Glue method one person had success with, but to no avail. The screw would not tighten enough and it striped out again. The only option left was to reinforce the hole. Stem Nut Fix The first step was to make a barrel or stem nut.

There is not much room beside the pin hole so I settled on a diameter of 0.100 inch for the stem. The through hole is drilled at 0.067" (#51) for a #2-56 thread. A small tapered flange will retain the stem nut in the frame. The overall length was decided at 0.190", a short step down in diameter to 0.096" for the first 0.050" in length of the stem nut which allows easy insertion in the frame after the old screw hole is carefully opened up to 0.096" (#41).

I used my Foredom rotary tool with a small round burr to reach in and chamfer the hole inside at the lug area just enough to seat the head of the stem nut flush and out of the way of the barrel lug. Start the stem on the inside with a set of needle nose pliers and finish with a pair of regular pliers opened up to pinch the nut and frame until seated flush.

No-Lathe Option For gunsmiths in need of performing this repair that don’t possess a lathe, I can supply the stem nut for $20.00 plus shipping from William Oliver G A little dab of Loctite Blue 242 on the screw will keep it from working loose. The counter sink in the washer goes up. Tighten the screw carefully just right—not too tight—to where the spring makes a good snap in the spring does two jobs.

It holds the slide stop in its place and holds the stop down until the empty mag overcomes it, locking the slide open. slide pin when it is seated. Insert the pin slowly and carefully to prevent bending the spring tail. The end of the spring must ride above the notch shelf on the pin. It is very easy to damage the spring. Properly installed the