Re: Non-Magical Helms

>Can Bards, Rangers, and Paladins run helms?

Yes. It doesn't say specifically how fast they run them; I would assume at
their casting level for spells.

>Also, are there any nonmagical helms that can reach spelljamming speed?

Not in vanilla. Depending upon how you view spelljamming (I tend to view it
as a magical triggering of a "natural" phenomenon, a sort of technomagic,
if you will) you might allow other sources of spelljamming velocity, like
gnomish inventions. Then again, if you think of it as being pure magic
(like a gigantic Fly spell), you might not. YMMV.

Hemlock