I've been playing with a modified Lee keyhole slug for a while now, it's been problematic until now as I've strived for a cheap slug load.
I started by filling in the key hole bit with metal putty and casting them, then loading them in trap loads they weighed about 20gm.
The results were about 4" at 35 yards but had flyers.
I then removed some off the tip and bought the weight up to 24gm, I loaded them the same and there was about a 3" group with less flyers.
I then filled the base in with rice when I loaded them, this was then shooting around 3" at 35 yards with no flyers. I moved out to 45 yards and groups were around me 6" which surprised me.
I then filled the base in with hot glue, groups at 45 yards were 5"-6" so I was almost at my goal.
I filed a bit more off the insert so they were a very nose heavy 26.5gm, I filled the hollow with hot glue again.
I took them out today and put a bigger 3-9 scope on for testing.
I was quite surprised not only have I made my 4" mark but I definitly surpassed it.

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