Is it safe to shoot tss shot through a factory full choke on a SBE 3. I know they say not to shoot steel through them, but was wondering about tss or hevi shot.

No.

Thank you.

It isn't just Benelli or a particular style of choke: TSS is considered under the same umbrella as steel. For most shotguns, unless it is marked "Steel Okay, SP for steelproof, etc." it means "lead only" which included bismuth.

Fabarm chokes are the exception in this regard: steel / TSS is approved up to the Exis 9/10 Extra Full.