The dummies with flat bases are a PITA. No matter how much you tell students, they still think they are rimfire. I have eliminated as many of them as I can from my stock. Now the ON CFO has mandated the primer pockets have to be filled in blue and the bullets have to be painted blue. There has to be a band of blue tape aroundthe barrel of the disabled firearms. Almost got a buzz from the blue nail polish.
At least you don't TELL your students that they're rimfires.
(Also, FMJ ammunition is illegal, semi automatics are the 'most dangerous' type of firearm, all centrefire magazines are capped to 5 rounds, and pointed bullets are illegal in Canada.