Agree with Toby. Spotting a bar lock just requires you yo look for the mainspring locating pin at the forward extremity of the lock.

A lot of cheaper guns were made as back-actions but so were lot of very expensive ones - the obvious being Purdey's island lock guns and Grant & Hodges patent side-levers, 90%+ of which seem to be back locks.

I find the weight in a bar lock is concentrated around the action a little more. All my personal hammer guns are bar-locks, not a conscious decision on my part but perhaps an interesting observation, they just feel right in the hand. That is just my opinion - the Marquis of Ripon pretty much exclusively used back action Purdey's - so what do I know! wink