The reason they are so rare is they were all destroyed, save about 25 or so. Those that are floating around are the ones that were salvaged from the scrap heap when they were all burnt in a deac attempt. I've handled one and ALMOST got the chance to fire it..damned it... but it would not fit the Mk.1 Springfield we had for some reason. Was NOT about to start fitting it... I'm sorting pictures and "junque" now, so if I find the close ups I took I'll try and send them to the site here.