From Packing.Org for Colorado:
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Carrying without a Permit/License
Date updated: Thursday, January 29, 2004
18-12-204. Permit Contents - Validity - Carrying Requirements.
(3) (a) a person who may lawfully possess a handgun may carry a handgun under the following circumstances without obtaining a permit and the handgun shall not be considered concealed:
(I) the handgun is in the possession of a person who is in a private automobile or in some other private means of conveyance and who carries the handgun for a legal use, including self-defense; or
(II) the handgun is in the possession of a person who is legally engaged in hunting activities within the state.
(b) the provisions of this subsection (3) shall not be construed to authorize the carrying of a handgun in violation of the provisions of section 18-12-105 or 18-12-105.5.
Peaceable journey law summary
Date updated: Thursday, March 11, 2004
See above under Car/Gun law summary.
Car/Gun law summary
Date updated: Saturday, May 10, 2003
18-12-204. Permit Contents - Validity - Carrying Requirements.
(3) (a) a person who may lawfully possess a handgun may carry a handgun under the following circumstances without obtaining a permit and the handgun shall not be considered concealed:
(I) the handgun is in the possession of a person who is in a private automobile or in some other private means of conveyance and who carries the handgun for a legal use, including self-defense…
See:
http://www.packing.org/state/index.jsp/colorado