Get your guns…
A 10,000 foot view…
First, forget everything you’ve ever seen in the movies, it’s all BS!
Take a moment and think about Newton’s laws, especially the 2nd and 3rd ones…
2nd law is F=m*a Force equals mass times acceleration
3rd law is equal and opposite reactions. Now thing about this for a second… In the movies, hitting someone with a (insert pistol or shotgun caliber here) blows them back through the door, out the window, etc. But the hero never moves or flinches. At best, the bad guy is going to collapse on the spot, if he doesn’t continue fighting.
Now a 50BMG ‘can’ blow an extremity off, but it’s not going to blow a bad guy’s head off unless you hit him ‘exactly’ perfect in the neck and rupture the spinal column. It will punch through and blow the ‘back’ of the head off and knock them down, but that’s it.
One shot kills… Sigh… That does happen occasionally, but not EVERY time. If the bad guy needs to be dead, ‘pay the insurance’, better known as shooting him again, preferably in the head.
Without getting into the weeds, you hear about shootouts/wars/etc. where people were shot multiple times and lived. All true. Go look up Moro rebellion in the Philippines, and their drugged out reaction to being shot with .38 pistols by the US Army. Hint- That gave rise to the 1911 and .45 caliber military pistols.
Early pistols/rifles were versions of various black powder types Rounds fired did not have the velocity of bullets today, and were mostly round or round nosed lead, so they flattened on impact and didn’t penetrate very deeply. Also calibers were and are different. Recoil is different depending on caliber too! Research your ‘era’ to make sure you’re actually getting the right weapons for your story, with the right bullet.
Remember there are TWO different measurements for bore/bullet diameters! DON’T swap them. E.g. a .45 doesn’t fire 9mm bullets…
Research is your friend. Always! Yes you might waste an hour or two, and it might be one sentence in your novel, but getting that one sentence on gun use right will pay dividends with the discerning reader.
Terminology- It’s important. Magazines vs. clips is one classic screw-up. Clips are used in M-1 Garands, and moon clips are used in some revolvers. Magazines are used in M-1 Carbines, and most modern semi-automatic pistols and rifles (Glock, AR-15, AKs). Another is a revolver with a safety, or a Glock with a safety, nope on both counts… Round count is another one. ‘Most’ modern revolvers have 6 rounds. Semi-automatic pistols (1911, Glock, etc.) can have anything from 6 (pocket pistols) to 33 rounds (Glock with extended magazine), however the ‘average’ is 13-17. Know the difference between fully automatic and semi-automatic, again research is your friend.
Quick examples- 1870s western- Rio ducked down, laboriously ejecting one case at a time from his single action. When he got to five, he reached behind the holster and pushed five more rounds out of his gunbelt into his hand. “Load one, skip one, load four,” he repeated the mantra his dad had taught him out loud, as he shoved new rounds into the pistol. Why? You never kept a live round under the hammer because it could go off if dropped. Also very specific as to single action. If you had said he swung the cylinder open, you’d get the cocked Labrador head look from the reader, and a shake of the head. And it might throw them out of the story.
2000s fiction- Rio ducked down, popped the magazine release on the Glock, pulled a new magazine from his mag carrier, slapped it in, racked the slide, and was back in action.
Time difference? The western way takes a proficient cowboy 12-15 seconds. The 2000 version, 2-3 seconds. Substitute a revolver in the 2000 sequence, and you’re talking 3-4 seconds with a speed loader.
There were multiple pistols, rifles, etc. available just about from day one. So it’s not necessarily realistic for ‘everyone’ to be using exactly the same gun, or everyone having exactly the same ammunition.
Accuracy- That comes from many, many hours of practice. And yes, there are ‘natural’ shooters, who actually do get better with practice, but they aren’t going to go diving through the air and shoot/kill six different bad guys as they fly through the air. The longer the barrel, the more accurate. A snub nose revolver (1-2inch barrel) is NOT accurate at 50 yards, just sayin…
The heroine isn’t going to pick up the 12ga shotgun and ‘magically’ kill everything in range the first time. Have her ‘trained’ by someone, or give her a .22 or an AR-15 (less recoil), easier to handle. A .22 will kill you as dead as anything else.
Ear protection is another issue. You shoot without earpro, you’re going to have tinnitus, or ringing in the ears. How you play that is up to you, but shooting then having a quiet word with somebody isn’t going to work. And the levels of noise are SIGNIFICANTLY different between outdoors, in a room, and in a car. They are also different between rifles, pistols, and shotguns.
Holsters are another one… sigh… In the old west the ‘Buscadero’ style holsters you see in all the movies DIDN’T EXIST! If they had holsters, they were on their belts, assuming they had belts. They might be open topped, or flap style like the military holsters, carried in saddle holsters on the saddle, or simply dropped in the pocket. Cross draw holsters came into a little bit of use probably in the 1870s-80s, but no one knows for sure. Today there is a plethora of holster options available, and once again, research is your friend.
Know the difference between cover and concealment. Yes, they ARE different.
Gunfights don’t last long, unless it is a siege or hostage environment. The reality is most are over in less than a minute.
Now let’s talk about science fiction, specifically military science fiction. Yes, laser weapons are possible, and being tested today, BUT they require a lot of power, so a megajoule pistol that burns through armor isn’t realistic. Right now that takes over a ton of batteries, and some seriously large super capacitors. Same with rifles.
Caseless ammunition- Yes, it exists today. But you’re not going to ‘load’ 500 rounds in a battle rifle and have it weigh 10 pounds unless they are BBs. Remember Newton’s third law, it happens in space too! In light gravity, if you fire a projectile weapon, it will move the shooter. Same in zero G, unless they are ‘tethered’ to something. If they are untethered, they would probably be spinning over and over… Does the term ‘Dutchman’ ring a bell?
Holographic sights are under development today, but be at least semi realistic! The sight isn’t going to ‘steer’ the projectile into the target. Also, the more powerful the scope or sight, the less field of view it will have (imagine trying to follow a specific ant on the ground while looking through a straw). A ‘realistic’ way to handle it would be a lock and zoom function for a shot, or a Heads Up Device (HUD) with the weapon following eye movement with a targeting carat on the HUD.
The difference between cover and concealment is that concealment stops vision, cover stops bullets (large calibers excluded unless you’re behind REALLY thick cover).
I’m going to quit here, but if there are specific questions, I’ll try to answer them.