There are few money-back guarantees in life, but I’ll give you one. If you dry-fire practice just 10 minutes a day, a few times a week, your shooting will improve by leaps and bounds. The problem for those who prefer striker-fired pistols like the Glock, M&P and XD family is that you have to rack the slide between each “dry” shot. That’s a pain. DryFireMags provide resistance to the trigger mechanism so you can replicate the trigger press of your gun without working the firing pin and without having to rack the slide. You can “tune” the mag so it provides its tactile click at the right point for the break of your trigger. You can also swap springs to reduce trigger weight. It’s a simple but brilliant invention. ($99–$109; dryfiremag.com)