The crane stocks will fit lipo sticks in the battery compartments
But I haven't seen an RS stock other than the crane that fits the sticks. Like you said, all other stocks advertised to hold CR123s won't fit the lipos
Anyway. This is airsoft, safe to assume everyone has an airsoft crane stock lol
And I get the feeling you guys are arguing the theoretical, this is already proven to work.
He's got a crane stock
He's got a Y adapter
He's got a lipo stick in both of the battery compartments
It works
This is on a PTW with a shortened board in the buffer tube, it's on the shortest position, and yes the cap goes on no problem