If you are reasonable with the officer that stops you and explain what you have in the car and why, he will probably have a look to verify.
He willl do a check on his computer and as long as your not committing any offences, or a prohibited person under the firearms act, you'll be on your way.
Many officers are a bit sketchy on the firearms legislation, so don't be surprised if he checks with his sergeant.

If however, you give him a hard time and refuse to answer his questions, he will do all the investigations down at the police station whilst you wait in a cell.

Best to be calm, polite and cooperative.

Ouch!