Yeah, plastic = no bueno......some models have a collared ferrule at.the very top of.the sleeve, a few tmags do-
and the ping g400 (which is actually rubber)-
I believe these are to eliminate any possibility of shaft breakage. IMO unnecessary! The ping also finishes off the club, like a normal ferrule, but it's flimsy as hell and you have to take care when pulling or it can get destroyed. The tmag is a regular collared ferrule and about 1/8" and the shank is about that length as well. Again you have to handle with care.when pulling or it's Gonzo! I don't know of any source to buy either.
Are you talking about having a ping style adapter that's finished off with a regular wood style ferrule? If that's the case then no big deal, as long as the ferrule size is common. Just can't stand buying additional pieces like the ping or tmag as they are never cheap; or some one off ferrule!
I'd suggest the tmag (without the small ferrule at the top!) or ping style that rickochet posted a pic of....cobra style is fine, not sure I really care for the teeth on the ferrule fitting into the hosel of the head, a bit clunky IMO.
