All Uberti guns including toggle link rifles, brass or steel frames, are made to use SAAMI spec (off the shelf) ammo. .357 or not. Just no +p or hot loads. Any one that tells you differently is misinformed. If you don't believe me, call Uberti. Phone: (301) 283-698 or (800) 264-4962
Uberti even just released a 1873 carbine in .44 magnum. Yes it is a toggle link gun.