Friday, August 17, 2012

Custom Crosman Breech--Part 5 Barrel Modification

Next up are the barrel modifications.

Chucked up about a 10" cutoff from a Crosman 2260 barrel into the Taig lathe and faced the breech end.  Deburred, beveled, polished... Essentially squared it up and cleaned it up.

Installed the barrel into the breech, and adjusted the barrel protrusion into the loading slot for a Marauder magazine.  Used a transfer punch to mark location for the transfer port.  Spotted with a center drill.

Followed by drilling the actual port with a #29 bit.

Added a .250" counterbore.

While the barrel was still in the milling machine, I milled small flat seats for the two set screws that lock the barrel into the steel breech.

And another flat for the shroud set screw.

Back to the Taig for the pellet leade.  A #2 bit was used.  Drilled to the front edge of the transfer port.  If the transfer port was drilled after the leade was finished, it would be very difficult to deburr the inside of the barrel.

With a small modified boring bar, I cut an internal groove between the end of the barrel and the transfer port hole.

Some cut and try until a #A009 o-ring fit into the groove.

Test fit.

Transfer port centers up nicely.   Next up will be the loading bolt.    Slowly getting there.

Thanks again for following along.  More in a few days.