Opened up a shot shell to see what was in it. Now I've got a couple questions.

[7Acres]

I decided I needed to know whether the 00 buckshot was steel shot or lead. So I opened it up. First thing I noticed was a bunch of what looked like laundry detergent. I dumped it out onto a paper towel. Then after that was out I noticed there may be room for a couple more 00 shot. So 2 questions:

1) What was the laundry detergent stuff?
2) This particular shell was a 3 1/2" shell with 18 pellets. Why didn't they put another couple pellets in there since it looked like there was room?

[Hickory]

Question #1
The stuff is a buffer to help keep the pellets uniform so they fly in a tighter group.

Question #2
I don't know.

[hubel458]

White stuff is GREX a shot cushioning medium, so that shot stays round
and helps patterns. Shot count is function the total weight that case
and powder combo is loaded to, to be within a certain pressure limit.
If you put more in may have to cut powder or use slower powder,
or be over limits.Ed

[7Acres]

Thanks for the answers! At what size shot does it start making sense to add GREX?

[375RUGER]

18-00buck is about 2-1/4 oz.

[dondiego]

GREX can be used to buffer any shot size. It has been proven to improve patterns.