CK 32, I may possibly have seen you shooting that at Prado. The reason you miss when aiming at the clays with a bead is that aiming with the bead likely gauantees a miss.
Your desire to keep a traditional non pistol grip stock is a good one.
Another reason for making it difficult to hit with a tactical 870 is if it has a fixed open choke. Your shot pattern tends to be blown out at ideal break points.
There is another guy, dastray with, a current thread who may want to sell his 870 field barrel. You may want to make a deal with him but keep your tactical barrel.
http://thefiringline.com/forums/showthread.php?t=488762