You'd better get rid of that full auto 1919 before your license as they're not on the C&R list!

Your question is a good one though. I have a new cherry C&R license.

First, as far as the C&R goes, it's a license to collect, not a business license. If you let it lapse, you can keep all the guns you bought with it. I believe you must keep your bound record book in case ATF wants to look at it a decade down the line.

As far as NFA items go, a dealer who lets his license lapse can keep the pre-86 dealer samples as his personal property. If he decides to sell them, however, he can only sell them to another dealer; if he dies, his estate cannot inherit them (they must be sold to a dealer). Post-86 dealer samples must be sold to other dealers if you let your license lapse.

As far as C&R NFA items go, you get to keep them but you lose the ability to buy and sell them interstate, and you also can no longer transport them interstate without filing a form 5320 with ATF beforehand.

I'm with JBear - the C&R license does not allow you to own anything that you cannot own as a non-FFL holder.  You would still need special licenses to own Class III in addition to the C&R.

The C&R allows you to buy everything on the C&R list directly, without going through another FFL holder or dealer.  I've had both my M1 Garand and a couple of old Mausers shipped directly to my house - so it has already paid for itself.

So, you don't have to do anything when your C&R expires, since it has to do with aquiring firearms, not owning them.

C&R firearms are all those 50 years or older (as noted above).  

Application papers were white last couple of times I've done (or renewed) mine.