Here are some low pressure pheasant loads that should do the job on a gobbler:
RST has 1 oz. 5s and 6s and is happy to mix and match case lots that go for $85. ARMUSA has lots of 12g stuff. GameBore 2 1/2" 1 oz in English 6s (US 7s) ALSO $85/case but sold at Cabela's by the box. PolyWad Vintager 7/8 oz 6s are $75/case