Nrs 202.350
So if the gun was tucked into waist band, and was showing, would it not be concealed?
Well, the arresting officer seemed to think it was concealed, so now we get to see how a prosecutor and judge view it.
I think if the pistol was plainly visible at all, and since he informed the officer of its presence right off, he was well within the law as I understand it, keeping in mind that officer notification isn't necessary in Nevada.
If his shirt was covering it, well...then its anyone's guess, and he may facing a "category C felony".
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http://www.leg.state.nv.us/Division/Legal/LawLibrary/NRS/NRS-202.html#NRS202Sec3653
NRS 202.350 Manufacture, importation, possession or use of dangerous weapon or silencer;
carrying concealed weapon without permit; penalties; issuance of permit to carry concealed weapon; exceptions.
1. Except as otherwise provided in this section and NRS 202.355 and 202.3653 to 202.369, inclusive,
a person within this State shall not:
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(d) Carry concealed upon his or her person any:
(1) Explosive substance, other than ammunition or any components thereof;
(2) Dirk, dagger or machete;
(3) Pistol, revolver or other firearm, or other dangerous or deadly weapon; or
(4) Knife which is made an integral part of a belt buckle.
2. Except as otherwise provided in NRS 202.275 and 212.185, a person who violates any of the provisions of:
(a) Paragraph (a) or (c) or subparagraph (2) or (4) of paragraph (d) of subsection 1 is guilty:
(1) For the first offense, of a gross misdemeanor.
(2) For any subsequent offense, of a category D felony and shall be punished as provided in NRS 193.130.
(b) Paragraph (b) or subparagraph (1) or (3) of paragraph (d) of subsection 1 is guilty of a category C felony and shall be punished as provided in NRS 193.130.
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NRS 193.130 Categories and punishment of felonies.
(c) A category C felony is a felony for which a court shall sentence a convicted person to imprisonment in the state prison for a minimum term of not less than 1 year and a maximum term of not more than 5 years. In addition to any other penalty, the court may impose a fine of not more than $10,000, unless a greater fine is authorized or required by statute.