Theoben Rapid MK2 mods

Figured rather than hijack other threads not to mention I just wanted to share my “end of winter project” . Rifle started out as a .25 cal ( that’s staying ) with a 23” long barrel and a standard 500cc aluminium cylinder and unregulated with free flow valve.It’s gone through a bit of a transformation. Here’s the list of mods and changes. None of which are my designs , mostly borrowed from members from various forums. Thanks gents , you know who you are.

-cleaned , steamed out dents then oiled up the stock

-Install missing rear sling stud and added a front stud

-fabricated cheek riser and wrapped to match

-fill port cover ( aluminium sleeve and Delrin)

-580cc best fittings bottle ( wrapped in CF vinyl)

-aluminium 30gr. Hammer with adjustable PIP and peek tip

-SSG with multi springs ( mild 30 fpe to wild 65fpe)

-17” LW barrel hand lapped , with a two port set up one at .2” the other at .150” , oring sealed . Clock barrel 90 degrees to change .

-force reduction valve stem and end cap to match . Got the idea from Mubhaur. Only one additional Oring

-picatinny rail added from m lock section

-custom roller bolt with oversized knob

-all ports matched from valve to match the block at .2”

I’m still waiting for a RAW V block and will have to modify the stock to fit. I currently have it tuned to peak at 40 FPE with a 20 fps spread over 4 magazines. That’s not terribly impressive but that’s from a 150bar fill shooting down to 100 bar. Basically 1 bar per shot. Very pleased with how it turned out. Classic rifle with a bit of a modern twist.

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Up to some more tricks. Valve version 4.0. This time I was able to reuse the stem I made but remade the end cap. This time with enough room for a cobra chamber. So this added two more o rings . The cobra chamber or “air spring” has a .052 vent and is roughly 1cc ,minus the area of the valve stem going through it. Give or take . I’m still going through the tuning but so far is much better that the stiff valve return spring I was using. I’m shooting for about 35 ft/lbs or 790fps with 25 grain JSB’s. I already have a heavy hitting 25 cal ( Leshiy 2) . Pics are of the parts disassembled and complete as drop in. I’m also still running the 7075 aluminum hammer and after three tins of pellets shows no signs of wear. Thanks for that tip Motorhead.

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