Is this one of those dealies where it's a regular Copal #1 shutter, but then on a sort of adapter to an odd-sized hole that's somewhere between #1 and #3 sized? I've had two of them, both Electric shutters.
One's on a Technika lensboard that I'm using/keeping, but the other one came on a different-brand lensboard that may or may not fit your beseler, I'll have a look when I get home...