Hello Ed, Welcome to MO from Midcoast Maine. I would try different ammo and see what that does before visiting a gunsmith. Some guns can shoot anything relatively well and some seem to be pickier. My 336SS does not like the 160 FTX Hornady rounds. I get 6 inch groups at 100 yards. Federal blue box 170gr groups at 3. I found a hand load using 150gr Core-lokt which groups under an inch. Every gun is different.
Also check out the scope mount to make sure everything is secure.