Broken Colt Diamondback 38 short butt D frame

As smkummer says, try scrubbing the under side of the ejector and it's seat in the rear of the cylinder.
Also scrub the front of the cylinder and rear of the barrel, and the breech face of the frame.

Revolvers have a problem with getting burned powder or other grit stuck under the ejector. When fired the grit can get really stuck, to the point that a brass "toothbrush" is sometimes needed to get it out.
It's also often difficult to see the debris.
This prevents the ejector from fully seating in the cylinder and causes sticky cylinder rotation or a jammed cylinder.

To avoid this, when ejecting fired cases hold the gun with the barrel pointing upward so the cases and any fouling will drop clear.

Also, a build up of fouling on the front of the cylinder and rear of the barrel can cause sticky cylinder rotation.
Use a bore solvent and a stiff toothbrush to clean these areas. You may even need a brass toothbrush here.
DO NOT attempt to remove all traces of firing from the cylinder, you'll only damage the finish.

Also scrub the face of the frame's breech around the firing pin bushing.

If this fails to correct the problem you'll probably need the services of a Colt qualified pistolsmith.
DO NOT take it to a local general gunsmith. Very few people these days really understand the old Colt action and you run a high risk of getting a damaged revolver back.

We recommend two forum members for Colt pistolsmithing. Both are Master pistolsmiths on Colt's.

Frank Glenn...
Has a top reputation here for top quality Colt work and excellent pricing and turnaround times.

Frank Glenn-Glenn Custom Complete Gunsmithing Service Glendale AZ

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