retex:
The case is chucked in a lathe and the crimp is applied with modified cir-clip pliers. As the crimp area heats up from friction, the pliers are gently squeezed resulting in the crimp you see in the photo.

I should add that we don't do this anymore, since Vic Pedersen has been making roll-crimpers as per the photo in Graeme Wright's book. The old collar-crimp is a bit time-consuming to set up each shell in the lathe, and can also come slightly loose if left in the second barrel during a couple of one-shot kills. Looks neat though! ...and according to the old catalogues, its more 'pukka' than the roll-crimp!

Although disgraceful to some, the use of modern plastic hulls is a convenience for high-volume buff and pig-hunting in northern Australia. Pick them up (literally!) at no cost, and no worries about losses in the field. With cast bullets, its the cheapest genuine 'big-bore' any of us will ever reload for!