phideaux2003,
It might be helpful to read what Bob Brister had to say on the subject; ("Shotgunning the Art and the Science")
...."This brings up another long-standing idea of shooters which is partly correct and partly untrue, the contention that adding velocity opens patterns and that reducing velocity tightens them. As a rule of thumb this idea is true. But it is not necessarily the velocity that makes the difference, it is the shot deformation. If shot are sufficiently hard to resist deformation at the higher pressures of high velocity, then they pattern about as well as the same shot at low velocity. I tested this with the highest velocity loads I have ever put through a gun barrel and with the hardest shot of them all-steel.
Canadian Industries (CIL) made some experimental loads of steel shot several years ago apperently with the intent of increasing penetration by increasing velocity. To be able to do this with reasonable pressures, they loaded a very hot powder charge behind a light load of 1 ounce of shot (12gauge) and obtained velocties said to be over 1,500 feet-per-second. I chronographed them at 1,450 feet-per-second, and thoroughly expected to see blown patterns with such velocity.
Instead those little loads patterned consistently better than 80 percent.
There is undoubtedly a slight pattern-opening effect from extreme velocityeven with steel shot, but it is nothing like that experienced with lead. I tested some high-velocity lead hunting loads containing No. 7 1/2 shot thatwere hard as most hunting loads produced in 1975 and early 76 and got 40-yard patterns around 68 percent from a full choke Perazzi. With the same gun, but the shot replaced by extra-hard, high antimony shot, the pattern jumped to 80 percent. The velocity was still there; the difference had been deformation."
Pete
