Speaking of WE M4 nozzles…
I found that the RA-Tech NPAS I own has a tendency to shift itself during firing, causing (up to) some pretty wild muzzle velocities by the end of a day on the field – something I’d rather not subject other players on the field to, provided I can even hit anything with the constantly fluctuating hop up setting required due to increased FPS.
Using the same concept of adding a shim behind the floating valve as per some of the FPS reduction kits for various GBB models, I’ve done this simple little trick to my WE M4 “Open Bolt” nozzles for a couple of years now.
This do-it-yourself mod is as simple as installing a washer or two, allowing for field-legal muzzle velocities while running higher pressure gases (i.e. MAPP) and tightbore barrels (in this case, an Angry Gun 6.03 x 360mm). I found that experimenting with different sizes of washers yielded different muzzle velocity results; thicker washers reduced muzzle velocity to a greater degree (similar to concept of adjustable valve length). I’ve seen other adjustable systems for other platforms that constrict or open up the front end of the nozzle, but I’m not yet sure how stable these are if applied to the WE system, in comparison.
Metal washers seemed to work more reliably over longer periods of time, though were often thinner in thickness. Washers with an outer diameter that were too small tended to dislodge during firing and get stuck in awkward positions within the loading nozzle, whereas I actually never experimented with washers with differing inner diameters but figure this to be an interesting experiment to see if there is any change for trial sometime in the future.
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