Though I am not a certified instructor, I have helped more than a few friends familiarize themselves with a new gun. I always make them do the same things I do when getting familiar with a new gun myself . . .
First, I practice with the gun unloaded, or using snap caps if I have them. Dry-firing a gun may not be a great idea for a firearm’s longevity or reliability, but it’s a damn site better than accidentally shooting yourself or someone else. I simply go through the regular routines of loading the gun, raising the weapon, making it ready, aiming down the sites, putting my finger on the trigger, pulling the trigger, maintaining a site picture (“follow through”), removing my finger from the trigger, making the weapon safe and lowering it. I repeat the process until I feel comfortable with every part of the firing sequence, from start to finish.
Then I load a single round into the gun. It doesn’t matter if it’s a handgun, shotgun, revolver, rifle, flair gun, or a pellet gun; it’s always a good idea for your first shot to not involve the “complication” of multiple rounds. This is especially true if the shooter is a novice. When I’m helping a friend get familiar with a new gun, a single shot helps me assess their capabilities—without worrying the need for an intra-ballistic intervention. If they drop the gun, let the muzzle climb too high, freak-out or aim the gun in an unsafe direction, they do so with an unloaded weapon.
One-shot-at-a-time methodology forces experienced shooters to concentrate on the gun, rather than their shooting. They get a better feel for the gun’s sound, recoil, trigger pull, accuracy, etc. when they don’t have to worry as much about the gun’s safety. Obviously, all the usual firearm safety rules apply, all the time, every time. But when a shooter knows that they they’re going to pause, regroup and rethink after every round, they’re more relaxed. And quickly gain confidence in their ability to master all aspects of the gun, including the gun’s administrative requirements, and the weapon itself.
That said, you never know what a gun you’ve never fired is going to do. The round may jam. It might fail to eject properly. The magazine might fall out. The dust cover might pop off. I’ve seen the entire upper receiver of a rifle come flying off with the first shot. It was most embarrassing, but I knew it was a limited TED (time exposed to danger) event. In the majority of situations leading to some sort of failure, the last thing you want is a repeat performance, courtesy another chambered round. Or an entire magazine of trouble.
Next, I load two rounds and fire them. This gets the new shooter used to firing consecutive shots before letting them go all movie and draining the mag without hitting a thing. Which is what all new shooters really want to do. Which is the last thing you want them to do. There are few things more dangerous than a runaway gun. It’s the one and only time that the “guns kill people” bumper stickers and T-shirts are right; the gun is shooting all by its self.
You never ever really know if a gun’s going to become a runaway until you’ve fired it. While it’s extremely rare, I’ve seen it happen. Feed a gun two rounds. If the new shooter freaks out, drops the gun or lets it go over their head, it’s highly likely that the second round will still head downrange. Sadly, I see this two-to-tango technique practiced less often then I see someone use a single round for the first time, even amongst shooters who should know better.
Finally, if you think the shooter and the gun are ready, go ahead and load three rounds. After a few strings of three rounds, it’s probably safe to fill the mag. By this point, you know how to make the gun go bang, and what to do after it’s done. Note: probably. I still advise extreme caution with a new gun until you’ve fired it enough to truly “know” it in the semi-Biblical sense. If there’s anything about the gun that gives you reason to pause, stick to feeding it one or two rounds at a time. Your friends may think you’re over-cautious, but there’s no such thing, really.
As for proceeding to advanced drills and variations, like the ones that led to Mr. Seymour’s fatal negligent discharge, it’s best to treat them the same way you would a new gun. Common sense suggests that you should practice any new technique with an unloaded gun until you know that you’re safe with it. Even then, remember that complexity killed the cat. Take all guns one step at a time, slowly and carefully and you’ll live to tell the tail.