I left three 7/10's last night. What am I doing wrong ? They appeared to be in the pocket, but I know something isn't right. Games were 219 one pocket split, 258 clean, 161 two pocket spilts. Thanks for positive input.

A lot probably depended on the foundation underneath. I would think a wood foundation leads to more 5-7 and lily than concrete foundations. 

I remember seeing the 5-7-10 on tv several times in one of the old syndicated series with Whispering Joe Smith.  Pretty sure I saw Dick Weber among others leave it.  I remember the first one I left was in practice at our student union lanes in college.

  Turning to the blow out seven ten that started this thread, we simply didn't see it with the entry angles achievable in the rubber ball days on lacquer.  When urethane lane finish replaced lacquer and they started stripping the back ends on a regular basis to try to combat carrydown, we started to see the pocket 7-10 in the mid 70's.  It has been with us ever since through the evolution to synthetic lanes and the change from soft polyester to urethane to resin enhanced urethane balls.