[502ci]

I have Moser axles with 1/2" x 3" studs that screw in.

If they are screwed all the way in, are tight, and are the same length when measuring them before you put the wheel on then it has to be something with the lug.

Are they acorn or shank style?

Acorn style would be obvious to the eye if it was longer so I'm gonna say you have shank style.

Are all the shanks the same length? Maybe one or however many your having a problem with are bottoming out just before it gets tight. Which would mean your wheel is not safely secured to your axle.