Hi, I have a similar vintage supersensitive with the all wire adjustable snares and I have not found a solution yo your problem either. I you find someone, please let me know.--THanks Ken

Here's two possible solutions, actually three...

1. remove the gut snares (if possible). Keep them off.

Or you can re-stretch them by soaking them for a few minutes in water and wire one end to a nail or hook (in your basement or garage) and weight the other end. Leave for a day or so to check on the length, if it's still short re-wet and hang. It will eventually stretch to a good length. (if the guts are real old they might break so be warned).

2. Plain or loose snare wires are not sold by anyone you'd have to buy a new set of snares (extended size) and cut or de-solder the wires off and replace the ones on your old one. You'll need a high temp solder tool and at least 60% silver solder, 80% would be better.

3. Buy a new replacement set that comes close. You may need to jerry-rig with wire, clips or drilling holes. Weigh your options.

a possible solution: replace gut and wire with heavy gage fishing line.

I made my own this way for an old snare. It works! Do you know you Boy Scout/Sailor knots? You'll need to tie a few tight knots to keep them from coming undone.