I've been singing the praises of the trulock choke for a while now. The more I shoot it, the better it gets. It's had about 200 rounds thru it so far. It puts up 225-230ish in the 10" at 30 and doesn't drop off too bad at 40. It does however, like to be squeaky clean between shots and shoots very consistent.
Here's the stats:
870 youth - 21" barrel (highly polished)
Trulock #7 choke (.560)
Fed HW - 3" #7's
40 yards - lasered 2x
63 degrees - 70% humidity - no wind
*The bigger black spots you see are multiple pellets in same holes*