Clever, functional ...easy to revert to original configuration and beats the socks off of a rubberband. You didn't say it was ferrous in so many words.....but will you blue it to match.... for stealth?
You may have to market your 'Walker lever-locker'!
Prolly won't blue it because of the braising for the join.
I made up about two or three of them some time ago (the brass ones) and put them on the evil bay.
They sold but I can't remember what they fetched.
These things could be made of plastic in an injection mold for about a penny a piece.
I doubt there is much of a market.... How many Walkers are out there?
I have one but I already bought one of the clips from me.
Actually, I didn't buy it from me. I traded it for a Remington Rolling Block in .45-70. I bought the RRB off of the Gunbroker and then traded it to me in exchange for the Walker clip.
I always wondered, what did they do in days old when knights were bold, Did they ignore a non problem? Did they tie a strip of leather lacing around the barrel or what. ( never owned a Walker ).
Is to work on the existing catch with a file and pliers. This is the easiest and most unobtrusive fix. But some folks recoil at going to town on the catch. If it breaks you are looking at a replacement.
I must hasten to add this caution.
I have not shot my Walker a lot with this clip installed. I know that it will remain in place with the muzzle pointing down. (It doesn't slide off) It doesn't seem to move because of recoil, remaining in place for six shots.
But I don't know if repeated use would have an effect on the finish of the barrel. I am afraid one might get some polishing similar to holster wear. The clip is lined with felt so it doesn't scratch. But it might rub.