Pattering with lo power shells ?

[Hitman 23]

Jus got my 870 sps turkey sm today and now I'm waiting on my ammo to arrive by weds.  I wana shoot my gun and adjust the point of impact to be close and fine tune it with my hunting loads, so would shooting  number 8 dove loads be a waste of time shooting it at 20 yds. This is my first turkey gun with adjustable sights. I have been using a nova and a lil Kentucky windage for a long time and I'm anxious to start pattering my gun. I suspect the dove loads to shoot lower than Win.LB .Any info would be appreciated.

[BigStrutter]

That's what I do. I shoot some at about 10- 15 paces so you can really tell where it's hitting. Go back to 20 yards shoot another then shoot one of your turkey loads. Adjust if needed and move back to 40 yards. Shoot another turkey load and fine tune your sights as you see fit and your done.

[d.winsor]

put a target at 12 yards, put a 1" square in the center, shoot your 2 3/4" shells.  Shoot as many times as necessary to adjust your poa and poi to shoot out the 1" square.  After you shoot out the 1" square move your target to 40 yards.  Use a 36 x 36" target and put a 1" square in the middle of it.  Now shoot your turkey loads.  Put up another target, adjust your sights to put the core of your pattern over the 1" square, now shoot another turkey load.  Shoot as many times as necessary to adjust the core of the pattern over the 1" square (Center of your target).  Use a rifle rest if you have one, you would be surprised how that little blue dot moves.  Use it at 12 yards also if you have it.  It will make your patterning quicker.