- A magazine-fed gun (either a pistol, rifle or energy weapon, I think it's one action?
- A revolver (I think three, unless you have a speed loader?)
- Bolt action/lever action rifles
- Break-action or pump-action shotguns without removable magazines (Where you have to feed new shells independently into the in-built magazine)
- A machine gun (one of the big ones you have to set up in place before using, fed with a belt or a big box magazine)
- Vehicle mounted weapons
- A minigun a la various video games
- A rocket launcher like a Bazooka
- Big stationary weapons like the L118 Light Howitzer, SAM sites etc.
Any I've forgotten would definitely be helpful as well, as well as references to where the rules are actually written down. IIRC, it always takes someone without the relevant weapon proficiency twice the number of actions it would take someone who knows what they're doing, but I can't for the life of me find that written down anywhere. I have books from all across the Megaverse, but tend to favour the versions of rules/proficiencies from Rifts Ultimate Edition, as it's a mega-conglomeration of many different books written up to that point.