Since I didn't want to post this twice, I posted it here
I found a source for a 7/8-14 Jam Nut
RCBS sells a Nut that is 7/8-14 X 0.265
It is basically the same size as the Set-Screw Lock Nut, RCBS uses, but without a Set-Screw
Its Part Number is 87505, and sells for $1.62 plus Tax and shipping
(And yeah, they DO charge Tax on an out of State order)