This has not previously been an issue, as the threads are machined to specifications on CNC equipment. We are not sure why you experienced a problem unless you have an older model with different threads. Your model may have 1/4-32 threads, which are very close in size to metric M6 × 0.75 threads.
Do not—and to repeat, do not ever—dry-fire a cap-and-ball revolver.
We do not recommend using Remington No. 11 caps because they are slightly shorter and may not completely cover the side vent holes. This could potentially cause a chain fire.
These products are recommended with items in your cart.