FX Wildcat MK2 Hammer Spring backing out

Got myself a MK2 in 177 with the X barrel. After tuning it, the gun’s a laser at 50 yards. The only problem am facing is the hammer spring knob keeps backing out. 

Every week or so it starts backing out and therefore reducing the power. I get to know this has happened since the accuracy drops at lower speeds. I then have to unscrew the stock, turn the hammer spring back in to get the power up, chrony it again etc. 

I DONT want to use loctite since I may want to tune the gun further. Is there an after market piece available which can be screwed on top of the hammer spring adjuster to keep it in place and ensure it doesn’t back out by itself. ?? Any help would be appreciated guys. 



Thanks in Advance. 
 
Why can't fx fix this? They use locknuts on other similar hammesprings.

Vibratight, mentioned above, is nice since you can still adjust the nut a handful of times after application, before it loses grip. Not super easy to clean out though (if you were to were it out and want to re-apply a clean coat).

Off topic, but do know what FPS/FPE you are shooting with what pellets?