Couple of weeks ago we were shooting in the backyard and had a sear/bolt spring turn loose on my Uberti Cattleman. I wasn't terribly upset, as I had a spare, and my elder son and I replaced it in short order. It looked like this:
After everyone went home, I Googled around and found that those flat steel springs are prone to break, right where mine broke. Those flat springs might be okay on a revolver that shoots a couple of hundred rounds a year, but our revolvers shoot a couple of thousand rounds a year.
The answer seems to be a wire spring, rather than flat steel, and they're made by both Wolfe and Heinie. They look like this:
The Heinie Spring is Brownells number 394-630-000WB
The Wolff Spring is Brownells number 969-322-940WB
I ordered a half-dozen of them to keep in the spares. We're shooting four different revolvers that might use these springs, so having a few spares is prudent. While I was at it, I ordered some Wolff reduced power springs for the Ruger Vaquero/Blackhawk.
The Wolff springs for the Vaquero/Blackhawk are Brownells Number 969-000-200WB.
I put those numbers up for my own reference, but I'm happy to share if anyone is interested.