40 yards is long for steel unless it was very large shot. Steel looses kenetic energy faster than any other type of shot. At close range it penetrates well, due to not deforming, but as it slows down it becomes a very poor penetrator. The lack of down range energy is one of the reasons that most factory steel shells are loaded so fast. They try to get more down range energy by starting the steel out at 1350-1400fps. Problem is that the light steel pellets loose velocity faster than any other material. So while they may start out much faster by 40 yards they have slowed down to the point that they have less than needed penetration ability. A lead shell, with large pellets starting out at 1150fps is more effective at 40 yards than steel which starts out 300+fps faster.
The laws of Physics are hard to overcome and steel does not get it done. Hence Heavyshot and Bismuth shot are better for long range shooting. Lead would be my first choice but why break the law and get another fine when you do not have to?
With lead 4,5 or even 6's might have gotten the job done at 40 yards. Steel 4's are no more effective at that range than 6's from what I have seen. If you were loosing steel 6's you were in even worse shape. They act like 7 1/2's at that range.
Only at extreme ranges does drop of shot enter the picture. I have killed, at long range, with 30 foot of forward and three to four foot elevation. But since lead is outlawed, no more. Even then, it was mostly to anchor a cripple. Those old 10's could really reach out there and save a lost bird when you did every thing right.
