No, I don't have the "twist lock" plug caps anymore. I'm now running the RC excel style caps that are just a force fit. Not sure what the friction mechanism is but they are generally VERY hard to remove (just like on my Saito FG-60 radial).
I actually made a nifty little slide hammer to remove these style plug caps. Very handy
!
When used carefully this baby is also much less abusive to the equipment