OT: syllabic rhotics [was Re: OT: Help reading Indic transliteration?]

Christophe Grandsire wrote:
>
> Still, to me approximants are about the easiest sounds to make syllabic
> to me, and I can't hear a length difference between [r\] and [r\=] when
> I pronounce them. Of course, the longer you maintain an approximant, the
> more likely it is gonna become syllabic, but length is not *necessary*
> for syllabicity.
Is there any difference between [r\=] and [@`]?