Another interesting couple of diagrams here. This one concerns the German WW1 13mm T-Gewehr Anti Tank rifle. This weapon proved highly dangerous to its firer if not fired in the correct manner. The weapon generated a chamber pressure of 18 tons and could easily break the firers shoulder if he did not position himself correctly when firing the weapon. The weapon required a two man crew for more than just the reason of lugging it and its ammunition. It was noted that after just three shots some of the firers would experience bleeding, eyes, ears and nose and concussion!! So the two man crew would alternate firing of the weapon. I did read an interesting piece about a German WW1 Infantry Gefrieter who was one of the first to use the weapon against a British tank at Cambrai. He had 20 rounds of ammo and it took 17 shots before the tank finally halted. One of the British crewmen was dead inside and the others were shot dead as they attempted to exit the tank-nasty business! As for the ammo its a 13mmx92SR brass case with bullet fitted with an armour piercing core of Tungsten. These rounds are collectors items in their own right as first production run rounds are dated April 1918 and dates up to Dec 1918 can be found though interestingly Nov 1918 dated examples are very very scarce indeed. Also check before you buy any complete inert rounds that the Armour Piercing core has been removed from the bullet. I know its a ridiculous sign of our draconian times but if you have any with the AP core intact they are subject to Section 5 of the UK Firearms Act and you could get into trouble. That said i do see these rounds clearly marked AP core removed at the shows and they go from around £50.00.