I've seen a lot of early two-way radios from Motorola that used the loctal tubes.  

Loctals were also used in quite a few models of commercial table- and portable-broadcast receivers.

My experience with repairing/restoring broadcast and shortwave radios that used loctals is that about 25% of the tubes/sockets become troublesome (at least one bad pin-to-socket connection in a quarter of the tubes). The result is a lot of wiggling of tubes in their sockets trying to get stable operation.  Deoxit helps but is not a complete answer to this particular problem.  

I've always wondered if the choice of metals or plating for the pins and/or the socket contacts is the problem.  Maybe dissimilar metals touching for years creates a difficult corrosion issue?

The loctal pins look like the same sort that were used in 7 and 9 pin miniature tubes but maybe the socket contacts are different?  I recall the loctals look like like they have less contact area and are like scissors biting the pin whereas the miniatures' socket contacts are wiping the pings with longer springy tabs.