Semi-Automatic, Revolver, Caliber, Cartridges: What You Need to Know When Buying a Gun

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By Daisy Luther

What do you really need to know before buying a gun? Last week, in the first installment of our series, we talked about some of the things you needed to think about, like how you plan to be using it and some basic definitions. But there’s a lot more to buying a gun that will work well for you than understanding what the words mean.

So, let’s move on to Part 2 of our Monday GunDay guest series by Steve Candidus, who has generously written these articles to make choosing a firearm easier.

What You Need to Know When Buying a Gun

By Steve Candidus

Revolvers vs. Semi-Automatics

Let’s start with an important note – your ammunition is not called bullets – that is what exits the barrel. The complete bullet, powder, and brass or aluminum case, is called a cartridge or round.


A revolver, sometimes called a wheel gun, has a cylinder typically holding five or six rounds. A semi-automatic is flatter in profile and typically holds more ammunition.  It fires a bullet each time the trigger is pulled, and extracts and ejects the spent cartridge case from the firing chamber, re-cocks the firing mechanism, and loads a new cartridge into the firing chamber.

Revolvers do not come with a safety. The trigger pull is longer and it takes more effort to fire them and thus acts as a safety – sort of. Revolvers come in sizes ranging from small pocket size guns to large heavy hunting guns. They are a good choice for home defense as their extra weight is actually an advantage. The weight absorbs more of the felt recoil.

They are loaded by releasing the cylinder button to the rear of the cylinder and swinging the cylinder out exposing the cartridges. By pushing on the cylinder rod that is located under the barrel when closed and in the center of the cylinder the rounds will be pushed out.

Cylinders can be reloaded either one at a time or with gadgets called speed loaders. These are plastic devices in the exact dimension of the cartridges in the cylinder and are held in place internally by small clips. By simply dropping the rounds into the cylinder and releasing the hold mechanism (a twist or a push) the entire cylinder is loaded very quickly.


Semi-Automatics, referred to as semi-autos, are thinner in profile and often carry more ammunition than revolvers.

Note that although some refer to them as ‘autos’ they are still not what is called ‘fully automatic’. A fully automatic weapon is classified as a machine gun. Assault weapons fall into this category and regardless of what you may hear or read in the news media, neither is easily accessible to the general public. These types of weapons require only one pull of the trigger to fire all of the rounds that the gun carries. We will not be discussing those types of guns here.

A semi-auto will only fire one bullet with each pull of the trigger.

Ammunition in a semi-automatic is contained in what’s called a magazine. It is a long rectangular enclosure that can be easily inserted and replaced for a quick reload for the gun. The magazine is located inside of the grip and will drop down to remove by pushing a magazine release button located just behind the trigger on the grip. To insert a new one, just push it in until it clicks.

A semi-auto with all of the rounds in the magazine in a single line is called a single stack. Those with alternating lines of ammo are called a double stack. Typically, a gun that will hold eight rounds in a single stack model will hold about fourteen or fifteen when designed as a double stack. These single stack/double stack magazines are not interchangeable. They are specific to the particular gun they were designed for.

Single stack semi-autos are smaller, lighter, thinner, and are usually more comfortable for smaller hands. They are also easier to conceal. You might consider a single stack auto in warm weather when wearing light clothing and a double stack in colder weather with heavier clothing.

Semi-Automatics come with a variety of different types of safety mechanisms called safeties. A passive safety is one that the shooter does not have to activate to set as on or off. The most common type of these look like a split trigger. One part is the firing mechanism and the other is the safety. When you place your finger on the trigger, it will automatically release the safety.

Some semi-autos also come with a grip safety. With a grip safety, the gun is set to safe until you hold it in your hand. That pushes the safety in and to the fire position.

There is also a manual safety on some semi-autos. These are usually located on the slide (that’s the part that moves) and offer an additional measure of safety at the expense of an extra motion that you must remember to initiate before firing.

Regardless of what you ultimately choose, the most important safety on your gun is to remember to NEVER put your index finger on the trigger until you are ready to fire the weapon!!! You might have seen some photos of someone holding a gun with their index finger alongside the barrel. That is where it should be until the exact moment that you intend to fire it.

Lastly, one of the topics that you might hear discussed is whether or not a particular auto has a firing pin. It might seem odd to someone not familiar with guns, but not all guns do. A company called Glock pioneered semi-autos with what are called strikers. They are a simple device and are very reliable. A firing pin is more complex. Both work equally well and your decision need not be based on one or the other. It is simply how the manufacturer designed them so don’t be intimidated by a highly knowledgeable gun person bringing them up. As the shooter you are indifferent.

Metal vs. Polymer

This refers to the material that most of the gun is made of.

Polymer, sometimes referred to as plastic, is a very strong and very light material that is used in constructing the frame (the guns skeleton) and its outside covering. Polymer guns are currently the most popular and because they are made from a mold rather than machined, they can be made with a comfortable and ergonomic grip.

Most polymer guns use a striker mechanism rather than a firing pin (see part 3 Revolvers vs. autos). In order to know whether your auto has a striker or a firing pin you can insert a pencil – eraser end first – into the barrel (making sure that the gun is unloaded first) and pull the trigger. If the pencil shoots up and sometimes even out it has a firing pin. If it barely moves, it has a striker.

Metal guns have an all-metal frame. Some use an aluminum alloy rather than steel to reduce weight, but all will usually be heavier than polymer guns.

The reason that there are more options available for you today for polymer guns than for metal guns is partly because they are lighter, but mostly because they are far less costly to manufacture. For a gun manufacturer, making a polymer gun from a mold is a lot less costly than machining one out of metal.

The barrel and the slide (the top part that moves backward when fired on semi-autos) on all semi-automatics are metal.

Revolvers are usually metal and heavier than semi-automatics.

All About Caliber

Caliber refers to the diameter of the bullet that exits the barrel. It can be a bit confusing too.

For instance, a .45ACP (auto) bullet has a diameter of .451 inches. A .357 magnum has a diameter of .357 inches, but so does a .38 caliber. A 9mm bullet has a diameter of 9.01mm or .355 inches, but so does a .380 auto.

The weight of the bullet is expressed in grains. For instance, a 9mm 115g means that the bullet is 9mm in diameter and it weighs 115 grains.

For personal defense, whether home or carry, the all-time king for stopping power is the .357 magnum. It is only available in revolvers but has the best record of stopping an assailant and in doing so quickly.

Any revolver that is chambered (designed) for .357 magnum will also shoot .38 specials safely. It is not true the other way around. You can NOT fire a .357 magnum round in a gun chambered for .38 special. First of all, it likely will not fit in the cylinder, but a .357 magnum has a lot more energy and would likely damage both the gun and hurt the shooter if they fired a .357 magnum in it.

The same is true for .44 special and .44 magnum.

If you chose a revolver a .357 magnum is a good choice and it can be loaded with the lesser recoiling, but still effective .38 specials or even .38 special +P’s if you can handle the increased recoil.

A ‘+P’ designation means that it is loaded to a higher power level than the standard non +P cartridge with the expected better stopping power and higher recoil.

.44 special and .44 magnum would likely not be a good choice for a new shooter as the weight of the gun and the recoil would both be high.

A few years ago, a new cartridge called .327 Federal magnum was introduced. It has much better stopping power than a .32 auto and has about 25% less felt recoil than its big brother the .357 magnum. It is a very good choice for the beginner that wants to use a revolver. I wish there were more gun choices for them.

For semi-autos, the .45 auto is arguably the king. I say arguably because the full power 10mm semi-auto (.400 inches) is right up there with it albeit with a bit snappier recoil. The tradeoff here is that you usually get at least one extra round of 10mm and better penetration to boot. The 10mm is more like a .357 magnum in a semi-automatic, but its recoil is difficult for the beginner to handle. Smith & Wesson makes a little brother called, not surprisingly, the .40S&W. It is very popular with police departments in the US and is a good choice for personal defense.

The most popular cartridge for automatic handguns is the 9mm. It is sometimes called 9mm Lugar or 9X19. The 19 refers to its case being 19mm long.

It’s the most popular handgun caliber in the world. Ammo is cheap, plentiful and available everywhere and there is probably a larger selection of handguns in 9mm than any other.

If you are planning on a lightweight handgun 115 grain HP’s are a good choice. The best option with a slightly heavier gun or if recoil is not the limiting factor then 124 grain +P’s are best.

The 9mm is not as powerful as the 40S&W or .45ACP, but the same size gun can hold more rounds and its power is more than adequate.

The smallest caliber that should be considered for autos is the .380ACP. Like the 10mm vs 40S&W, it’s the little brother to the 9mm. Note that its stopping power is marginal and many of the guns available for this caliber are not very reliable. That’s not a good thing for a weapon that you might have to depend on for your life, but if that is what you comfortable with and you have a gun that shoots it reliably go for it.

In a pinch, even a 22LR will do. They are small, economic, and recoil is very light. Although dismissed as ‘mouse guns’, don’t dismiss the .22LR. They are used commonly by some of the world’s spy agencies like the Israeli Mossad. You can carry one in an ankle holster or in a purse and hardly even notice that you are carrying it.

Remember that the ‘mouse’ gun that you have with when you need it is 100% more effective than the portable cannon that you left at home because it was too heavy to carry around all the time.

Whatever caliber you ultimately decide on, aside from the safety slugs mentioned earlier for home defense, hollow point bullets are best for self-defense.

How Weight Affects Recoil

Although weight is not an issue with a gun for home defense, it is a big issue for something that you intend to carry all day and perhaps every day.

Remember when looking at the weight of the gun that you also have to factor in the weight of the ammunition. The total weight is what you need to consider.

As with the caliber selection where the more powerful the caliber the greater the recoil, the lighter the gun the greater the recoil will be.

It goes back to Isaac Newton’s law that every action has an equal and opposite reaction.

Polymer guns are inherently light and although seemingly attractive for carrying, they will also yield a stronger felt recoil. The better ergonomics that can be built into them due to ease of manufacturing them with complex contours versus metal guns helps some, but the laws of physics are not to be denied. The lighter the gun the greater the recoil.

An all steel gun will weigh the most and with the same caliber will have the least recoil. Metal alloy guns (steel slide and barrel with an aluminum frame) weigh less and recoil a little more. The new exotic metal (titanium) guns are lighter still but will have the greatest recoil of all metal guns.

Polymer is lighter than metal and felt recoil will be higher.

You will need to find the best compromise of weight versus recoil. It is different for everyone. It will also vary by experience. The more you shoot the more you will become comfortable with recoil.

Find a balance between the most powerful caliber that you can comfortably handle and the highest weight gun that you want to carry.

Anything to add? Any questions?

This is the basic information you’ll need when buying a gun, but no amount of textbook knowledge can take the place of experience. Just “having a gun” isn’t enough. Everyone should seek high-quality civilian firearms training.

Before buying a gun, the most important advice I can give you is to find an instructor who will let you test a variety of guns. My gun store allows you to test different models but they charge you about $10 per gun to shoot five rounds through. It’s worth it, though, to make sure you like and are comfortable with the firearm you are about to purchase. Would you buy a car without a test drive? The same philosophy should also hold true when buying a gun.

For example, my former instructor and good friend carries an M&P Shield. It’s her favorite gun and she was convinced I’d love it, too. When I shot it I felt like I couldn’t hit the broad side of a barn and couldn’t wait to go back to my Glock.

Anything to add or any questions? Leave them in the comments section below.


Picture of Steve Candidus

Steve Candidus

Steve Candidus is a writer and a history buff that works as a product and application specialist of large AC electric motors in Spring, Texas. You can write to him here.

Leave a Reply

  • Thanks for the good info. I appreciate the emphasis on gun weight and recoil. This is huge as I have seen many beginners at the gun shop enchanted with small lightweight handguns. Everything changes when you get to the range an struggle to get through a box of ammo. Shooting should be fun or at least a useful learned skill and the more practice the better!

    best regards and God bless

    • I gave my Wife a S&W Mod 640-1 which is the .357mg version in all stainless steel. I have a Mod. 340PD which is a titanium/alloy hybrid in the .357mg. Very lite and a hand full shooting the magnums. I bought oversize Pachmayr grips to help tame the recoil.

  • Two thoughts: my wife had a ,380 she found that her hands can not always work the slide so she went back to a ,38 special. I carry a S&W model 60 loaded with 180 gr hard cast around home but change to hollow points when we go to the city. We have had big bears break into two buildings over the years. We do live in rural Alaska.

    • If your wife has trouble working the slide on a semi-auto then she made the right decision to go back to a .38 special revolver.

      Hard cast bullets in .357 magnum will give very good penetration on large predators like bears, but you are correct that hollow points are better for self defense against against two-legged ones. The 125 grain hollow point in .357 magnum is the number one best man-stopper round available – if you can handle the recoil.

      Thanks for sharing your thoughts.

      Steve C.
      Spring, Texas

  • While the author is almost correct when he describes the difference between “bullets” and cartridges, he’s actually only correct from a technical standpoint. In common usage, many people, perhaps even most people, refer to cartridges as bullets. As with so many other evolutions of word meaning in our ever-changing vocabulary, the technical distinction is something which is more of historical than current accuracy, except perhaps for reloaders.

  • Ok you lost me about half way through. The 357 is NOT the ultimate man stopper and it is NOT only available in a revolver

  • Yeah, yeah. Always a coupla maroobs whining there’s an exceptation like the Coonan semi-Auto 357, or who think carrying a 454 casull makes sense. This was an article for newbies to help them make a sensible choice. Damn fine attempt at it, might have been better in book form.
    I’ve gone back to 357 revolvin guns myself the last few years, after seeing three city cops in the news loose 48 rounds from 3 glocks in 5 seconds at a fleeing perp, and manage to hit some poor old lady two blocks away sitting on her doorstep. Havin only 6 rounds does a lot for your focus, instead of relying on hysteria fire-suppression.
    By the way, you should see what 357 does out of a rifle barrel. My 357 Timberwolf hits like a truck at 2200 fps out of an 18 in barrel.. Long barrel runs the preasure way up.

  • Unless your assailant is someone wearing body armor or you encounter a large animal like a bear, then caliber shouldn’t matter in terms of “stopping power”. Technology has made caliber more of a personal preference. A 9mm hollow point defense round can leave a just as damaging a wound as a .40 or higher. If you shoot someone with a hollow point defense round you’re almost guaranteed to stop them no matter the caliber, unless, again, they’re wearing body armor, a large animal like a bear, or a person so insanely doped out on drugs that nothing short of a hit to the heart or head would stop them.

  • GLOCK did not ‘pioneer’ the striker fire. FN-Browning Model 1900, and the Borchardt of 1893 were BOTH striker fired. There were early manually operated pistols with strikers Passler-Seidl

  • A revolver, sometimes called a wheel gun, has a cylinder typically holding five or six rounds. A semi-automatic is flatter in profile and typically holds more ammunition. It fires a bullet each time the trigger is pulled, and extracts and ejects the spent cartridge case from the firing chamber, re-cocks the firing mechanism, and loads a new cartridge into the firing chamber.

    Please review and edit….incorrect info…it describes a semiautomatic.

  • All in all not a bad article.
    Keeps to the basics, stays out of the weeds.

    I would of stayed away from the caliber debate. For every person who likes/hates a round, you have 2 or 3 more hate/like it.
    In the end it comes down to shot placement anyways.
    That is just me.

    As many would advise anyone new to handguns, looking for a first time buy, research, get out there and try as many different brands and calibers as possible, take into price point consideration, intended use, and make an informed decision.

    If possible, take a NRA class.

    After making your purchase, practice!

  • A well presented and thought out article Steve. As always, choices in fire arms are wide and varied and you covered the basics very well.

    Just to add a couple of thoughts of my own: I personally carry a Millenium 9mm Taurus double stack magazine which for a composite handgun has a tolerable recoil and lots of rounds ( 12 + 1 ) for up close and personal scenarios. A very good quality weapon for a moderate price. I use Hornady high powered Home defense hollow points which have plastic center piece placed in the hollow point which keeps the round from fouling in fabric and clothing the attacker may be wearing. I carry this handgun most everywhere.

    For a handgun that I’m going to be putting hundreds or thousands of round through while practicing I like to upgrade to a Sig Sauer, S&W, Remington or Glock for their dependability and accuracy.

    If I’m out in the sticks I’ll carry my .44 Magnum Ruger which is single action ( wheel gun ).

    As a gun salesman I have to ask a lot of questions of the customer and make several recommendations based on the customers perceived needs. For instance, I get a lot of safety related questions concerning an actual safety mechanism on the weapon. Personally, I don’t want to waste the time to click off a safety and give an aggressor the advantage so I’ll recommend a hammerless Lady Smith double action .38 Special. No hammer to hang up on your clothing should you need it. Very safe as well.

    I subscribe to the old safety adage ” keep your booger hook off the bang switch ” and you’ll be just fine.

    I highly recommend taking a CCW permit class with a Certified trainer before making any decisions on a fire arm. A person is much better able to make a choice based on the course.

    For me, as a handgun owner for over 40 years I have a couple of preferred choices and calibers that I’m comfortable with so I would recommend that a newer gun owner do your research and make your choice accordingly because your life may depend upon it.


    Snake Plisken

    • 1stMarine and Patrick,

      All good thoughts.

      We cover the all-important practice part in a later article because you are so right. No matter what choice you ultimately make, PRACTICE is the key!

      A mouse gun that a person is comfortable with, can shoot accurately, functions reliably, and that they will have with them when they need it is much more important than worrying about the caliber.

      My usual carry gun is a third generation S&W 9mm. I carry a 5904 double stack (15 in the magazine and one up the spout) in winter and a 3913NL single stack (8 in the magazine and one up the spout) in summer.

      I will carry a full power 10mm S&W 1006 if I feel some special need, but I really don’t ever feel outgunned with a 9mm. It’s heavy, but it carries well in a shoulder holster (also covered in an upcoming article).

      A note here about my personal choice of those S&W third generation semi-autos:

      Technology has progressed some in the thirty years since I started using them, but the familiarity that I have with them is more important than the small improvements made in newer guns since. For the new gun buyer I always suggest that they get whatever is the newest at the time and stay with it. The familiarity that they will ultimately develop is more important than the newest gee-wiz designs that will undoubtedly come about later.

      I am also of the old Massad Ayoob School of having those extra safeties – a manual safety on the slide and a magazine safety that renders the gun inoperable if not fully engaged. I am conditioned enough though that I work them automatically without even worrying about having to remember them. That only comes with years of practice.

      But, Daisy asked me to write these articles with the first time buyer in mind so I have tried to keep things simple and easy for the beginner.

      Any and all input and suggestions to that end are very much appreciated.

      Thanks again for your comments.

      Steve C.
      Spring, Texas

  • Very thorough and informative. I have a question though. Would you recommend keeping a round in the chamber? I have heard many reports of how a round in the chamber helps, but I’m uncomfortable with the thought of having such power so accessible, especially when there are small children around. Who can forget stories of toddlers accidentally shooting a family member?

    Currently, my interest in handguns is only in revolvers and semi-automatics with a manual safety, but I was hoping that you could write an article showing evidence of which option would actually be better. A round in the chamber? Manual safety? Grip safety? Handguns with a heavier trigger pull? Please write about this, as I don’t want to end up as one of the roughly 400 people accidentally shot by a toddler. Thanks ????

  • Another fine article on Daisy’s fine website!
    A question I don’t how to answer, maybe I’m pondering too much, but I have two Ruger Revolvers and only experience IN revolvers, would a 9MM from any manufacturer may “confuse” me in a time of crisis or self-defense? I ask from the thinking of “muscle memory”, (I’m an RN). We train ourselves and then there is a time where “muscle memory” “takes over”, to get you thru an activity.
    A scenario is whatever gun is on my bedside table and need it in the dark…Do you think if I was scared, that I may fumble or be clumsy with a semi-auto vs the revolver? I understand I am only as good as my practicing and learning with both styles, but I have always been curious about this.
    SIDE NOTE: I had an old Triumph motorcycle that shifted on the right, and I literally had to “reprogram and practice” starting, panic stops, etc. so I could reach for the correct pedal in time of need. There were times I hit the wrong pedal most certainly, so with this situation in mind I ask my question! Thank You very much!

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