I have an 1865 Spencer carbine, Burnside mfg. It has the split Stabler ring, and has the 50 centerfire breach block installed. problem. the block drops but if too much pressure is put on the lever, it over rides the stabler and locks up. only way to free is to unscrew the stabler and return breach block to upright position.Using it single fire is difficult.
Solution. The center fire breach block will spring over the stabler causing it to override and lock up because there is a space between them.. I placed a small piece of nylon about 1/16 inch thick and 1/4 by 1/4 inch between the center fire block and the carbine block. This prevents the block from springing to over ride the cutoff and it holds in position. I've tried pushing it hard and it will not over ride the cutoff lever. Now it can be used as a single shot as intended.
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the cutoff was over riding on the down stroke and locking up. I epoxied a small piece of hard nylon to give it a ‘stop’. It worked. the stabler engages the block on the way down and locks. A hard push and no overriding movement. It does not touch the original gun parts. I think the center fire block is a not quite perfect fit, and the original rim fire block would not need this. I tried some dummies in the mag and it cycles perfectly.
Picture shows the shim, and the full down stroke of the block.
(Photo Added by Two Flints)
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It works.... the repair is invisible, and the piece of nylon with a drop of epoxy does not touch the original parts, yet holds in place, and does the trick. (It does not have to come to each edge of the block, cut it short so you really can't see it at all.)
Solved........Ken