Okay guys. Today the Benji 392/392 mod is a full length 7/8" diamter barrel that protrudes two inches past the tube (may trim a little more off).
What was done: Two telescopic brass tubes are used. The first tube that slips over the factory tube is 11/32 I.D. by .014 wall. The next tube is a 7/16" O.D. (thick walled) that is a telescopic fit over the 11/32" tube.
A slot on both tubes needed to be cut along the entire lengths. As each tube is applied, the slot needs to be cut wider to accomadate for the radius gains. The slot ends at the muzzle. The final tube is soldered in place, of course.
What does this do? Allows for "devices" to be used.
The larger diameter 'barrel' now has a much wider solder base along the pump tube which adds a great deal of strength to the overall design. used was 380-420 degree solder lead-tin mix, rather low heat stuff because I did not want to fudge the factory solder joints or risk having things come apart.
The end plug needed (of course) a small radius/indent added that matches the amount of barrel that now falls below the front plug (overlapping effect of the barrel in relation to the tube). All is in a perfect straight line - perfect alignment - looks liek a factory job.
Oh, that black thing leaning against the wall? That is the barrel assembly for a three-barreled paintball minigun I am almost finished with...
"Well, I thought it was a rabbit but it turned out to be Bear Grylls in a rabbit hide."