The slot of the cleanout screw of a used Traditions Trapper pistol
that I bought was buggered which made it a pain to remove.
But I finally got it out after soaking it in Liquid Wrench.
I determined that the replacement screw for CVA/Traditions is
a 5M x 5mm so I went to the nearest True Value hardware store
where I found that the only replacements that they had were
hardened and blued hex head screws in 5M X 5mm, 5M x 6mm
and 5M x 8mm.
I tried the 8mm first but found that it was too long and protruded
from the drum too much.
I settled on the 6mm because the 5mm simply looked too small
without a flat head and easy to lose.
The 6mm fits great but will hit the nipple threads if it's screwed
all of the way in. So I simply reverse the screw a partial turn
from that point and it fits perfectly.
I also bought a 4.5mm allen wrench to turn it with.
Total cost for the screw and wrench was $1.38 with tax, so I
bought another one of each as a spare.
It's good enough until I get some original screws, and I like the
fact that this replacement screw is hardened and already blued.