As above -treat later Mk 1 blocks as Mk 2 for fitting purposes as by that time the blocks were unified with different bottle valves and triggers in identical units. Personally I don't like Mk 2 actions in Mk 1 stocks but others do. The ambi stocks sold later are differentiated from early ones by the recess in the base of the stock to accommodate the blanking plug under the block. Early ambi stocks don't have this feature as the blocks were flat underneath without the plug UNLESS someone had drilled the block for QF or pressure gauge.
Last edited by Rapidnick; 16-07-2018 at 08:22 AM.
'It may be that your sole purpose in life is to serve as a warning to others'.