Here comes a stupid question: I'd like to install the spring and plunger into the FSB on a Romak II and thread the barrel since I can't find a 22mm FSB; what I don't see is how it is retained in the FSB? Most FSBs I've dealt with have the pins on the top side of the barrel, and the front pin is what retains the plunger. The Romak pins are on the underside, with one pin in the top rear. Does it take a different type of plunger than the notched type on an AKM? What retains it without a front pin? Queue the simple answer that will make me feel stupid!