Hi,
I have one of the above spring air rifles. It is .177 and has a barrel locking device. It is of the break barrel variety and has the Licoln Jeffries name and address stamped into the stock. Judging by it's size and weight I would say it was a 'junior' model. I can find a lot of information on the under lever guns before BSA took them over, but can find no trace of a break barrel model. It has a wood stock and a metal tubular forend (spring housing). The iron sights are non adjustable, apart from being tappable from either side within their dovetail, but no elevation adjustment. The gun works well enough if a little heavy on the trigger. Any information greatly appreciated.