Hi Harry,
After I dump the shot into the shell I simple try to center the BPI X-Stream spreader insert (
http://www.ballisticproducts.com/X-S...tinfo/3220001/ ) on top of the shot and push it down. The X insert weighs close to nothing so one doesn't have to worry about it concerning increasing pressure. The X insert does displace close to 1/8 oz of shot so please allow for an increased shot volume.
I often do not get the X insert centered but it either if doesn't matter much or luck has always been on my side when shooting them in a 10 gauge. I use the same inserts in 12 gauge loads with good results. The inserts seem to open the pattern a degree or two of choke. A full choke may open to mod or more. I think I got more opening (spread) with the 10 gauge than the 12 gauge. I do not have any data to back that up, only memory of broken targets.
Using the X inserts in my Big Friend Ten, a high condition 10 lb, 32" 10 gauge DH, with .030" bore constrictions, I shot 75% on the sporting clays course at the UP Shoot. That score put me in the top 20% of shooters at that shoot which was far above my normal ability!!!! Using the X's I also managed to break a lot of "in my face" targets at Hausman's Hidden Hollow this summer. My Parker shooting mates were so impressed that my nickname for my 10 lb DH quickly stuck. The BFT!
Respectfully,
Mark