Derrick, our Ohio correspondent, is at it again, modifying a Crosman 38T.
Self-centering. Not the stock cylinder. Ebay! Nobody named Derrick noticed the big hole in the middle of the cylinder till later. I had no idea that Crosman used two different cylinders in 38Ts. They both started as .177 cylinders. Just over 1/16" in hole diameter difference. This one is too loose on the pin. Need to turn a bushing later.
Brass Crosman SSP 250 barrel in .20 cal.
Holy cow! Udder madness. The inside of the shroud tapers? I think they were trying to put weight (metal) at the muzzle without using a heavy barrel. I bored the muzzle end out to 7/16"--to match the OD of the new barrel.
Taig time. Crowning the .20 cal bbl. Also cut the breech with a small taper to guide the pellet into the rifling. Notice that I re-faced my 3-jaw chuck faces. There was some kind of industrial accident that had previously rendered them "gouged". Also cleaned up the business ends.
I like the recessed target crown. It adds a bit of extra visual appeal for an extra minute or two of time. I've found that it's essential when finishing the crown's bevel to start from the center and work towards the outer edge. So many simple things that I have to figure out for myself. I'd never thought about how the metal pulls in the direction that you're cutting.
Groovy. The o-rings provide a press fit into the shroud's varying ID and effectively centers the barrel. 2 steps at the breech. I'm not sure why. I think I was going in a different design direction and made a change. The barrel is about 2" too long. Left extra length to allow fitting at the cylinder.
Much more to come...
Sunday, October 12, 2008
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