I acquired a Rossi Coach Gun, 20 ga. SxS with exposed hammers. It misfired from day one. I've run through my spring assortment and can't find any that will give a good hammer blow. Firing pins are fine and hammers strike the pins on center, everything moves freely and seems right but hammers are very easy to cock and thus strike a very light blow that will not fire the primer. The springs are about ,250 OD and wire diameter is about .050" but just seems too light.
Any suggestions as to where I could find heavier coils?

Two spots Coyote. Go to Taurus's website, they own Rossi and will have replacement parts for it.

The second place to try is Brownell's. Send them the specs on the spring you need and they probably have it.

Here's the links you need.

www.brownells.com/Default.aspx

www.taurususa.com/main/index.cfm

Many thanks, I'll give it a try.