By the close of 1942 it was apparent that the Q.F. 2 pounder had reached it’s sell-by date, with the new APCBC ammunition taking the cannon to its current limits. This was acceptable, the 17 pounder was beginning to make its way onto the field and the 6 pounder was beginning to make it’s way onto vehicles, ensuring that the British would continue to have capable Anti-tank weapons in the future. There were, however, niche roles that would continue using the 2 pounder. The first was that of a glider capable tank for the airborne. No 6 pounder equipped vehicle could fit with the gliders, and antitank capability was still needed. The second was armored cars, most of which would still be using the 2 pounder. Increasing the anti-tank potential of the 2 pounder for these roles would be valuable to their continued success.
To improve the 2 pounder, a squeezebore adaptor was created to be fitted to the end of the barrel of the gun. This was to be utilized with special tungsten cored ammunition with a soft steel jacket that would be squeezed down by the adapter, preventing excess gas from passing the round and increasing muzzle velocity. Trials showed that with the MK 1 APSV (armored piercing super velocity) shot the 2 pounder could penetrate 145 mm of flat armor point blank, and could still defeat 100mm of armor at 30 degrees at up to 200 yards. a Mk 2 APSV was developed with a heavier core that could only penetrate 120mm of flat armor, but would behave better against angled armor and performed better at range.
While the adapter did see some limited service with the airborne tanks, its main usage was on the Daimler Armored Car. With a scout troop typically consisting of 2 scout cars and 2 armored cars, having one of the 2 armored cars be issued with a littlejohn adaptor was not uncommon. This was usually viewed as a golden ratio, as the littlejohn adaptor removed the possibility of using a HE shell.
Personally, I think that driving around in this little armored car and zipping through the turrets of Panthers and the hulls of Tigers is just great. Anyway, stats are below, sources for this are the ‘Handbook for the Armored Car, Daimler I and II’,’ Workshop Manual for the Armored Car, Daimler I and II’, and for the proliferation of the Littlejohn adaptor I will quote the following websites