TS Spring won't fit the Grant,i bought some and they're too small. Did your cartos work on the Grant at first ?
The centre post is floating on my Grant, if you look at the base of the top cap there is a brass circle,push it towards the cap then put your carto on.
The upper cap had this little button and if you raise the button, it is held by a screw and another little piece undeneath (I can't see if it is plastic or metal). Yes, I did use cartos and had no problems the first day. However, the top cap button was completly attached to the center and not moving. I just pushed it back in (use a 510 adapter) and nothing. Got the spring somewhat fixed and bought a dozen another spring (none fit). Going to see a member today, maybe he can help. What about the top button screw, would it help to tighten that? Thank you all