Bumper material for Mackbrass 410CC?

[royjohn]

I bought some 3/16", red silicone O-rings, 70 durometer, for replacement bumpers for my Mackbrass 410 CC,
but I find they are too thin. Apparently what is in the horn was stock that was cut down from something
larger to fit. Does anybody have a source for the proper stock for this?

Meanwhile I have four, 4 inch, 3/16" diameter O-rings which I can't use...if they will fit your horn, PM me
with your postal address and I will send you some...
TIA,
royjohn

[The Brute Squad]

Have you tried reaching out to Chris from Mack Brass directly?