Just thought I'd share some details on a project I've just finished up....a 2078 bulk fill build.
Following an airgun lull I was looking for something to restart the ol' mojo, and remembered a bulk fill tube I'd come across 4 or 5yrs ago that was sitting on the shelf-
Basically a cylinder threaded either end, 1 complete valve (brass) and 1 valve body (S/S painted black for some reason).
The maker was trying to do a HPA build, but the valve was all wrong with its flat seat, 6.35mm throat and stem-
I did try it on Co2, but with the standard hammer spring maxed out it was horrific to cock, and only made 5fpe) so......it was modding time.....
I bored the brass body out and turned up a PEEK seat and delrin poppet (matched/ lapped at 45deg).....
.....and converted the other S/S valve body into a check valve/ fill port, with matching probe-
The insert in the fill valve was left long so I could use it as a fixing point for the end barrel support later on-
With this new valve a lighter hammer was required, so turned one up from oilon (similar to mds) with a PEEK striker face and S/S core, increased throw and weighing in at 30gr-
Running negative preload and aided by the new oversized cocking bolt, its now 1 finger cocking.....
......and producing upto 12fpe (at 18deg C) through a modded/ sleeved 20" .177 crosman barrel.
Also made up a fairly basic offset RVA to make things easier during the testing phase.....
.....and after some polishing and powder coating (light texture satin black, on my little tribostatic home set up) the action was sorted-
This just left the stock! I did strip back the original TH stock, only to find the most bland and unattractive lump of beech you've ever seen in your life, so following some work to the pistol grip, and a little sharpening up around the edges, it went of to a mates body shop for a lick of paint.....BMW/Mini 'Hot chocolate metallic'-
Absolutely over the moon with how this has come out, and after giving the crosman barrel a fair bit of attention, it stacks ftt's at 25m (bottom shot a sighter, then 5 or 6 in group above) -
Looking forward to some warmer weather and trying this out to 50m next.
Anywho, long post so sorry about that, and if you've made it this far......thank you
Following an airgun lull I was looking for something to restart the ol' mojo, and remembered a bulk fill tube I'd come across 4 or 5yrs ago that was sitting on the shelf-
Basically a cylinder threaded either end, 1 complete valve (brass) and 1 valve body (S/S painted black for some reason).
The maker was trying to do a HPA build, but the valve was all wrong with its flat seat, 6.35mm throat and stem-
I did try it on Co2, but with the standard hammer spring maxed out it was horrific to cock, and only made 5fpe) so......it was modding time.....
I bored the brass body out and turned up a PEEK seat and delrin poppet (matched/ lapped at 45deg).....
.....and converted the other S/S valve body into a check valve/ fill port, with matching probe-
The insert in the fill valve was left long so I could use it as a fixing point for the end barrel support later on-
With this new valve a lighter hammer was required, so turned one up from oilon (similar to mds) with a PEEK striker face and S/S core, increased throw and weighing in at 30gr-
Running negative preload and aided by the new oversized cocking bolt, its now 1 finger cocking.....
......and producing upto 12fpe (at 18deg C) through a modded/ sleeved 20" .177 crosman barrel.
Also made up a fairly basic offset RVA to make things easier during the testing phase.....
.....and after some polishing and powder coating (light texture satin black, on my little tribostatic home set up) the action was sorted-
This just left the stock! I did strip back the original TH stock, only to find the most bland and unattractive lump of beech you've ever seen in your life, so following some work to the pistol grip, and a little sharpening up around the edges, it went of to a mates body shop for a lick of paint.....BMW/Mini 'Hot chocolate metallic'-
Absolutely over the moon with how this has come out, and after giving the crosman barrel a fair bit of attention, it stacks ftt's at 25m (bottom shot a sighter, then 5 or 6 in group above) -
Looking forward to some warmer weather and trying this out to 50m next.
Anywho, long post so sorry about that, and if you've made it this far......thank you

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