Leaping with gay abandon over the shark ... again

The BATFE needs to be defunded, now.  In its latest derangement, it has decided that a shipment of Airsoft toy guns could be converted "with minimal work" to machineguns, and confiscated them for destruction.  The store owner quite reasonably points out that even if you were able to successfully modify them to chamber live rounds of actual ammunition and get the firing pin to strike the primer, the result would blow up in your face.  (On the bright side, at least this time BATFE didn't incinerate anyone, and hasn't yet killed anyone. One wonders whether "minimal work" includes fabricating a complete new barrel and bolt from scratch in their machine shops.  They've done comparable things before.)

I've said it before, and I'll say it again.  BATFE is out of control and needs to be disbanded, and its agents prohibited from securing further employment in law enforcement.

Are credit card numbers predictable?

I pay attention to numbers.  It's one of those Aspie traits.  In particular, something has struck me about credit and debit card numbers.

You see, those numbers are all 16-digit numbers that appear on the card in groups of four.  Some of those digits are coded; for instance, the first digit is always 5 for a Mastercard, 4 for a VISA.  In general, the first four digits identify the card issuer and the type of card, as I understand it.  But one would then expect a high degree of randomness in the remaining 12 digits, or at least a lack of visible correlation between the remaining 12 digits and the identity of the cardholder.

This does not, in fact, appear to be the case.  I have observed over a period of quite a few years now that there is a strong tendency for a comparatively small number of groups to appear again and again in the numbers of cards issued to the same individual, even from different issuers.  There also appears to be some tendency for CVV numbers to repeat.

This makes me wonder whether it might in fact be possible to predict, with a reasonable success rate, the numbers of cards issued to a particular individual, if you know the numbers of cards issued to that individual in the past.  If so, and if you can do this for a number of different cardholders, I further wonder whether it might be possible to take the identifying information for an arbitrary individual and predict (again, with a reasonable success rate) the numbers and CVVs of cards likely to have been issued to that individual.