If asked, simply reply with a yes. If the officer feels the need to search your vehicle and finds all your kit, you could possibly be fined and have all your stuff seized if he really wants to. All of which is bad news for you. Be informative of what you have, your intentions and never grab for something without telling him/her what you're reaching for. Sure, everything may look like legit firearms but if the officer see's that you're storing it properly, well educated in your sport and aren't a complete moron ie. going to take something out of the case and brandish it in the public to cause problems he may just write you a ticket for whatever traffic infraction you were stopped for and let you be on your way. Or like a previous member mentioned he might call in one of his superiors for advice before you're cleared to go. Being a dick and being difficult to the officer will only hurt you in the long run.
If the officer DOESN'T ask if you have weapons in the car, don't volunteer information. But don't deny anything either. Calm your nerves and try not to look agitated. He may think somethings wrong and hold you on suspicion. It also depends on the person who pulls you over. I've never been pulled over but if I ever was, this is the way I would handle it.
The Distance Between Courage & Stupidity Is Exactly Nine Millimeters