Hello, I have a Componon 300/5.6 and have removed the front and rear cells from the iris barrel in the center. The Componon has a thread diameter of 56mm on each cell which would make it an ideal candidate for the #3S Copal which as the dimension for the front and rear throat; according to the SKGrimes site. Now the problem is that the iris barrel has a rim to rim thickness of 38.5mm whereas the #3S Copal has a thickness of 28.6mm, so the rear cell would never catch the rear threads of the throat. Measurement of the depth of the rear throat on the iris barrel gives me 15mm. So any shutter that had the right size thread throat, front and rear, would also have to have a throat depth of 15mm in back. You mention that the boss is as long as on Compound .

My question is, is the boss long enough to accommodate the rear cell of the Componon 300. If the shutter fits the specs, then I would be very happy