Enforce What?

[james_bond_007]

That's what I was getting at, but unless they catch it in transit, they couldn't prove it other wise

How about yet another scenario:

1) You arrive in TENN on 30JUN13
2) You go get your mags (and even buy some more mags from your friends back in TENN)
3) You now own and possess mags prior to 01JUL13 (NOTE: HB1224 does not say anything about WHERE you can own and possess them).
4) You return to Colorado on 06JUL13 with the mags (giving yourself time for your hangover from the party on the 4th to go away before driving back)

Technically, you have met all requirements of HB1224 and own and possess legally grandfathered mags.

....but try telling that to the cop that stops you on your way back.