I know this thread is outdated but hopefully someone will read this and this might help.
I patterned the 3.5 LB #5 with the .650 and the .664 and the patterns at 50 yards were almost identical.
How is that possible?
I would have thought the .650 would be too tight and deform the pellets.
I see that the recommended constriction for this shell out of this gun is .680!
Im confused.
Any insight would be appreciated