I have a Cadet that will chamber and fire factory 32-20 ammo, but the accuracy is poor. The barrel is stamped 31-12-120.

What I did:

Shorten Starline Brass to 1.100"
Fire form using the COW method
Use correct Cadet healed bullet RCBS .310-120-RN (P/N:82023), tumble lube with Lee Liquid Alox
4.6grs Universal Clays powder, small pistol primers
I don't use dies, just hand seat bullets, and I don't resize the fired brass, just decap

Excellent accuracy and long case life