danf1234 Posted May 5 Posted May 5 I have 4 TM MWS variants that all have Federal Concepts NPAS valves, but I have gone done the HPA route and bought adapters from airtac. question I have is should I change the NPAS valve back to standard as I am seeing a 10 fps fluctuation which I wasn’t expecting with HPA?
Supporters Adolf Hamster Posted May 5 Supporters Posted May 5 It could be worth trying. Although you're gonna have X psi requirement to get a good cycle, which might put you over the limit so you'd need some method of dropping it back down. Shimming a standard rocket valve does the same thing as an npas, and might be more repeatable, or a shorter inner barrel can do the job too (dont worry if it's shorter than the outer)
GiantKiwi Posted May 5 Posted May 5 (edited) How old are your FEDA's? This sounds like the old 3D printed resin ones which really, really don't like staying consistent as the adjustment screw has a tendency to walk from them as threadlock can't bind to the resin. Edited May 5 by GiantKiwi clarity
LMKipper Posted May 6 Posted May 6 The issue you will have is that you'll often need a fairly high pressure for the rifle to cycle consistently. Airsoft green gas/propane is around 140psi at room temperature, so that's a good place to start with a reg setting, then see if you need the NPAS to bring it down to playable limits.
GiantKiwi Posted May 7 Posted May 7 (edited) 10 hours ago, LMKipper said: The issue you will have is that you'll often need a fairly high pressure for the rifle to cycle consistently. Airsoft green gas/propane is around 140psi at room temperature, so that's a good place to start with a reg setting, then see if you need the NPAS to bring it down to playable limits. Vapor pressure of propane at room temperature of 25 degrees C is 8.3bar / 122PSI On 06/05/2025 at 07:12, danf1234 said: They are the older 3D printed ones yes Probably need to be removing them then, if you can make them work without the NPAS great, but I doubt it. If you need a UK supplier of a better NPAS, Jaeger Precision makes them as well https://jaegerprecision.co.uk/products/jaeger-precision-mws-npas-adjustable-valve Edited May 7 by GiantKiwi
danf1234 Posted May 9 Author Posted May 9 Just bought 7 Jaeger Precision valves to kit out all my RIFs for HPA Nick G and GiantKiwi 2
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