Strawb on here (steve) was using evolve grease on his Eion (egoframe/ion conversion) and was having trouble achieving certain velocitys with consistency and out of curiosity he used some petroleum jelly on the bolt to see how it would work and it completely transformed his gun, shoots sweet as anything.
I have a giant tub of morrisons (no not the supermarket) petroleum jelly which is used in industry specificaly for pnuematic applications which is what he used, it appears to be a slightly different consistency than vas.
I dont think there is anything wrong with using petroleum jelly atall so long as you lube it more regularly because it does tend to thin out a little quicker than other lubes.
tbh you could use thin oil on the orings of a spool valve marker and it would run far sweeter than with these thick greases, you would just have to lube it after every days play.
I would pm strawb and ask him how hes getting on.
PS: vas works brilliantly in regs regaurdless.