[natman]

BTW......48 pellets in a 10'' circle at 40 yards is an extremely good pattern.

By wingshooting standards, perhaps, but it's a pretty poor turkey pattern. There's about 315 #4 pellets in a 2 1/4 oz. turkey load. If you are only getting 48 of them in the circle, that's ~15% coverage. According to the National Wild Turkey Foundation coverage should be a much higher percentage:

Two ounces of No. 4s (approx. 135 pellets/oz.) should result in a 37-percent pattern.
http://www.nwtf.org/tips_adventures/tips.php?id=13279

Which would result in 100+ pellets in the center, a much better turkey pattern. Results with an extra 1/4 ounce should be even higher.

The ideal pattern for turkey hunting is 100 pellets in a 10-inch circle at 40 yards.
ibid

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Note to the OP:

Try a different choke, try 3" loads. It's not unusual for a 3" load to pattern better than a 3.5, especially from a standard diameter barrel.