OmniTL (multiple Tech Levels)

[weby]

Originally Posted by ericthered

By RAW, you can't really buy an advantage or that gives you all versions of your TL skills at TL8 and TL4. Much for the same reason you can't buy an advantage or perk that gives you both engineering (civil) and engineering (chemical) with the same skill points: they're actually different skills, for the most part.
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But you can buy a perk that allows you to use a weapon with a different weapon skill.

[sir_pudding]

The anachronistic training technique in GURPS Infinite Worlds is also a thing.