Every trip through Canada can be a different event. I tried to follow everyone's rules as best I could during our move. Canada has a lot of information on the rules on the web. There is a phone number somewhere you can call up and ask a real person specific questions. Canada did not ask for an exact count of our ammo. I always used the phrase: "We have no more than 5K rounds, primers, pieces of brass, etc." Things that were easy to count (5 bricks of primers = 5K) I counted and estimated things that I couldn't. Some ammo boxes had 24 rounds of ammo and 26 pieces of fired brass times many many boxes. I made sure I was on the low side of 5K total (for each of us) for any item. Exact weight for powder. I had the amounts of stuff I had written down, but they never asked.
Canada asked a lot of questions about why we had so much ammo, etc., but no guns. They would ask the same question in slightly different ways. They were always nice to us. The one time we did have guns we made sure all were "Fudd" long guns (plus a Garand) and had our paperwork filled out. There was not enough lines on the form for the amount we had, so we filled out 2 forms and had the fees for both in hand...the officer combined both forms together and saved us some cash.