les: Early season birds will likely be a bit slower to flush, meaning closer shots. On the other hand, typical hunting in S.D. is "wide open spaces" and, in my experience, shots presented can be pretty long. Not real helpful, I guess, but I don't know where you'll be hunting. In general, I'd say a pre-war Model 21 will be a great choice, and I don't think you'll regret a Mod/Full choke combination.
My advice, though, is to never go on a hunt like this without a back-up shotgun. Take another, and preferably one with a Skeet and/or IC choke. That way, if the birds are flushing real close, you can switch to your more open-choked gun.
On my first trip to S.D. I took my Dad's 1941 Remington Model 11 Sportsman, which went there with him on many trips in the 50s and 60s. In the middle of nowhere, a half-hour from the nearest anything, I shot at a rooster and the Simmons rib "let go," making the gun unfirable. Fortunately, I had my Superlight along, or I would have been S.O.L.
Have a great trip! Shoot 4s and 6s, take a great dog for the days and some good whisky for the evenings. TT
Last edited by Two Triggers; 09/29/09 09:31 PM.