Should You Have Only One Caliber?

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Last Updated on December 1, 2020

The great thing about hindsight is all the wisdom it produces. How many of you have ever wished you could go back in time to a point in your life with all of the knowledge you have now? A lot of us would like to do High School or College over with the brains of our more mature selves.

This could be because you know so much more about what kinds of trouble that would be fun to get into, but most likely it is to make better decisions than you did in the past. For me at least, I have said the same thing on occasion about how my life would be so much different knowing then what I know now.

However, I know with absolute certainty that my life wouldn’t be the same as it is now. I might not have made the decisions that connected the dots that made it possible to meet my wife. My children may have never been born, or I could have died at some earlier point in my life by getting into that trouble I spoke of and then everything would have been worse, not better. Morbid, right?

Well, let’s use the old gift of hindsight for a specific question that is common to preppers and found on many prepper blogs like the Prepper Journal. Instead of asking for a total life do over, I wanted to give my perspective on the subject of which weapons to buy. Specifically, this is about whether or not you should standardize on a caliber or you should acquire as many different calibers as you can. If I had to use what I know now and asked myself the question back then of should you have only one caliber, what would I tell myself?

This question is similar to one I have been meaning to write about for some time on the Prepper Journal, but I had someone ask me specifically so I decided that now was the best time. A reader, Jason asked the following:

I have one question and that I have discussed with a few friends and it is in a SHTF situation would you rather have multiple weapons with the same ammo type or different ammo types. For example would you rather have a 9mm .45 and a .380 or just three 9mils. I think it would be easier to stock pile just one type of ammo but possibly easier to scavenge and search for multiple types. Just looking for your opinion and thanks for all the info.  – Jason

What are the benefits of standardizing weapon calibers?

This is a great question that has been debated all over the place. Now, I am not going to deal with specifically what I think the single best pistol caliber is, but I do have some thoughts on making purchases that could be the most effective in a SHTF event. Let’s take Jason’s hypothetical scenario here and that is a SHTF type of world. If you knew that was coming and could make all your purchases now what would you purchase and why? For me, this question is pretty easy to comment on and I will go on to explain why I have done the exact opposite of what I recommend now.

Select one caliber and stick with it.
Select one caliber and stick with it.

Assuming you have already done your research on answering the question of what is the best handgun for self defense. If I was planning on purchasing the firearms I needed for a SHTF world and money was no major concern, I would standardize on one single caliber and actually one single make/model of firearm.

Why is that? The first reason is precisely what Jason describes above. If you only have to purchase one type of ammo, your life just got a lot simpler.

Let’s say you choose 9mm as your caliber of choice for whatever reason and you have 4 people in your immediate family or survival group who are going to be capable of defending your home/retreat/apartment or neighborhood. It only makes sense that you would all have the same ammunition in your weapons.

I would take that a step further and say that ideally, you would all have the same model handgun as well. I am not advocating any particular model or manufacturer, but let’s say you all have Glock 19’s. You would have the advantage of having the same ammo and the same magazines.

Buying ammunition in bulk is so much more cost-effective and ammo isn’t cheap. Neither are Glock magazines, but you do have an advantage in that if you are shooting your Glock 19 and run out of ammo, your buddy can throw you one of their magazines from their Glock and it will just work.

Now, in the same caliber, Glock magazines (and I assume there are other manufacturers too) will work with the same caliber handguns. That Glock 19 magazine will work in any Glock chambered in 9mm, so that means your magazines will also work with a Glock 17, 26 or 34. This is something important to think about. (Update: You can’t use the 19 in the 17 because the magazine for the 19 is shorter. You can use the 17 in the 19 though…Thanks to Kris for that catch.)

It is the same with rifle platforms. If you could only have one rifle caliber, what would it be? I prefer the AR15 but I know there are a ton of people who recommend the AK. Either is perfectly fine in my opinion but if you are looking at equipping a larger force, it is much better if you are all using the same rounds in your weapon and your magazines all work with each other’s weapons.

What are the benefits of having multiple calibers?

The flip side of this coin usually goes something like this. What if I can’t find any ammo in my chosen caliber, or I run out of one caliber? It would make sense to diversify, right? I don’t necessarily think this is important enough to hang a strategy on, but there are always special cases.

For instance, what if your chosen pistol caliber was one that wasn’t as common as say 9mm or .45 or .40? What about .357? I know there are always going to be people to debate the merits of one pistol caliber over another and that isn’t what this post is about. I think we can make the case though that it is wiser to standardize on one of the top 3 handgun calibers that are sold today. For defensive rounds, you are looking at the same three I mentioned above. 9mm, .40, and .45 so I recommend you choose one of those, and if your plan is to purchase multiple firearms for a group to use for the scenario of the SHTF, select a manufacturer you trust and stock up on ammo.

Is this what I did? No and I will tell you why which hopefully doesn’t negate everything I said above. When I started purchasing firearms, I had no thought in my mind of doomsday. I had never heard the terms TEOTWAWKI or SHTF; I just wanted a pistol for self-defense. The first pistol I purchased was a Glock 17 and I made this purchase on a couple of factors that didn’t take any of the perspective (hindsight) above into consideration. The first was price. I purchased a factory remanufactured Glock because it saved me some money. I think my Glock 17 was about $290 when I purchased it, maybe $300 – wish I could still get a Glock for that price.

It wasn’t until many years later that I purchased another handgun and it wasn’t a Glock and it wasn’t even a 9mm. It was a Beretta chambered in .40. Why did I buy this gun? Because I loved it! It felt so good in my hand and it was beautiful. Was I thinking about how my family would be able to interchange magazines? Was I thinking about purchasing a whole new stock of ammo? Nope, I wanted that firearm because I wanted it.

The next weapon was a .380 and that was simply for concealed carry but again, I wasn’t taking the factors above into consideration exactly. I was certainly by this time thinking of protecting my family, but the .380 was always and only going to be a concealed weapon. I don’t even stock more than a couple of boxes of ammo for that because if we really do go through SHTF, I won’t be rocking that little .380 I can promise you that.

I have since sold the Beretta and purchased another Glock chambered in .40 as well as acquired a .45 along the way as a gift. I have not followed my own advice through the years, but I didn’t have the benefit of hindsight. I do have three weapons though in the most common calibers mentioned above. Those same calibers are the first to sell out, but they are also the first to be restocked. You do have a pretty high probability of running into someone who uses the same caliber as one of those too so it isn’t a total wash.

I imagine that most if not all of you who purchased firearms in the past made similar decisions due to money constraints or other factors that the average person deals with just like me. I do know that going forward, any purchase will be the same manufacturer (I just like Glock) and the same caliber. It will be the same with rifles too and there is a beautiful AR that I have my eyes on.

Hope that was helpful to someone and keep those questions/comments coming.

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Freedom-loving American doing what I can to help prepare and inform others. Editor and creator of The Prepper Journal 2013-2017, 2020 -

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I don’t think there is anything wrong with picking a single or a couple calipers. I love .45 but it is a lil much for my wife and kids so i also have a .40 and 9mm. I think it is a great idea to own only a few caliber a but multiple of the same make such as I have two 1911s. I do plan on buying another 9 mm in the glock platform. My thoughts are “if” i struggle to find 1 caliber hopefully I will find another. As far as battle rifles I’m a AR guy. Shotguns… Read more »


The one thing that I am SO happy to see here is no immediate suggestion (or any mention, for that matter) that everyone go out and get a .22. I’ve looked at the merits of standardizing ammo. Don’t get me wrong, AWESOME idea. Definitely keeps the need for stocking different calibers down to a minimum (even if you can get a caliber that will fit your handgun along with your rifle – yes, I know, that probably means a .22). I, for one, have a handgun and a shotgun. I need to work on getting my reserves up, but I… Read more »


I would definitely agree that people normally don’ start out their buying of firearms with a common round in mind. I think it would be good to have all the same round, as long as your family or whoever you are prepping with can handle that round. I personally have a variety of firearms and have a few more in mind that I want to purchase based on my wants and likes alone. Eventually I will probably start to standardize my rounds. And for Long gun I have been and always will be a fan on the M1A. Just so… Read more »

J Bryan

When I started building my inventory of ammo. I never thought about a single caliber, but recently I’ve had some thoughts about the reason to only have the least amount of calibers to meet my needs. I’ve settled on 9mm, .40, .45, .223/5.56mm, .308. 12ga. now you can go wow!!! How do you cut down the calibers? The only thing I’ve considered dropping is the .45 although I love my .45. My .357’s I’m just not building anymore. Part of my reasoning is if we’re on the move the ammo is so heavy. Most police officers and gang members are… Read more »

J Bryan

Yes, P Henry the need for .22 is important. I also have a .177 pellet, bow and crossbow. It’s all a matter of what the situations going to be. SHTF, right after or later their could be a lot of ammo available. If I’m at home it doesn’t matter to me personally what calibers, but if I’m moving that’s the question. My thoughts were the same as retiredarmydad if I have to find ammo I want to play the odds that police, military, etc…will have what I need. I also believe each area is different, as our police force mainly… Read more »

Jeff Stevens

Not sure if the Army or police will be keen on giving us their ammo. If you are thinking of scavenging though, well that makes sense.

Hillbilly in Ok.

Another good thing with the Glock is you can buy a Just Right carbine in the same caliber. It will use the same Glock mags. Than you have a pistol and rifle that share both amo and mags. Well written article, but I am from the other mind set. The biggest problem I see with the multi caliber idea is carrying capacity in a SHTF situation. However I do see a big advantage from the scavenging standpoint. I have this debate with a close friend of mine at every get together and I do think he has a good point… Read more »


If you stock up on ammo, it doesn’t matter what caliber, because you’re stocked up. When ammo gets scarce, everyone will be looking for the common ones. Once, last year, I couldn’t get a single box of 9mm, but I could get 10 boxes of 38s.

Neil Stuckey

I pondered on this issue for months, trying to find the right caliber and the right gun. I ended up just sticking with the tried and true Mossburg 500 with 18.5 barrel synthetic stock and fore end nothing fancy. I painted the bead with glow in the dark orange paint. attached a sling and a saddle 5 shell holder and added a magazine tube flashlight mount with a surefire LED light. To me the Mossburg is the right tool because of its multiple uses. Shotguns can drop large and small game, breach doors, wide range variety of common calibers ammo.… Read more »

Neil Stuckey

I cannot stress enough how much proper training with your weapon is. I took some defensive gun training courses in Kentucky with some x-special forces guys and was amazed at how much a course helped me especially with a pistol. With long guns i don’t feel much changed from where i was at before but with a pistol, night and day different. I am deadly at 20 yards with multiple targets. My speed at taking out multiple targets from draw is pretty impressive for me at 20 yards. I can even double tap pretty good at 10-15 yards but not… Read more »

Neil Stuckey

I like what John said. I think if a SHTF situation it will either be from virus outbreak or war/nuclear war scenario. And i think he is right if this happens i think peoples first instincts are to run. They will bottle up together on highways and interstates not realizing they just screwed themselves. Looting will come next then that is where people start turning on each other for supplies. After that things will settle down. Homes will be empty and i imagine finding what you need will be pretty easy. Its just making it to that point it could… Read more »


I am with the mindset that you can’t go wrong with the type of weapons and ammo that military and LE use. That way parts and ammo will always be available.


2 Glock 45s, 1 Aerosport 45 using Glock mags, 2 40s, 2 9 MM, 3 38-357, 1 AR, 30-06, 308. Left any out? Oh yeah just for grins, rifle and pistol combos in 44 mag, 45 Long Colt, and 22. Why so many? Things break, and I think I got almost all major caliburs covered. AK, maybe later. Stockpiling a box or so a week. Takes time for sure, but I know I’m covered. But, each to their own situation.


Personally, I like having 3 choices in calibers. I have a 9mm, 12 ga, and ,223…. I have a couple of survival .22 rifles that break down into a nice backpack sort of weapon. I don’t plan on running out of ammo, but in case I do, these would be the best choices to find in my opinion, plus the most usable… you have to think about hunting for food as well as personal defense.


The break down .22 is a Henry rifle that all fits in the stock, and floats. Water is important to me since I spend much of my time in a sailboat. I searched all the gun shows for a long time and couldn’t find one so I bought a new one. The very next show I found one, that’s why I have 2, great little guns that fit in my back pack.


Very well thought out and thanks for your perspective. Like you, when I purchesed my first hand gun I had no thoughts of SHTF. A police officer told me that a .45 was best for (Home) self defense. Since then I have added several new hand guns and have kept to 9mm. All rifles are 5.56 and .22, as a standard. So I try to limit the types of ammo I need to purchase. Thanks again for your insight.


I think that it is best to try to cover as many bases as possible without owning a truckload of firearms. I think the Glock 23 is a great combo semi-auto. With a 40-9 conversion barrel, an extra .357Sig barrel, and some magazines for the Glock 22, 23, 17, 19, 31, and/or 32 you are then able to shoot the 9mm, the .357Sig, and the .40S&W. The S&W 686 makes a decent combo revolver being able to shoot .38 Special, .38 Special +P, and .357 Magnum. And I round out the SHTF handguns with a S&W 63 which gives me… Read more »


I have read all the comments and have done some pondering. I think prepping has a lot to do with having a back up plan. If I need to cook, do I have only one way to start a fire? Or 1 stove? I believe in some kind of redundancy, if u have 1 caliber at least make sure u have some kind of back whether it is the same model of gun of a completely different setup. To each their own but to even have this conversation shows us avenues to prep that maybe we didn’t think of at… Read more »


In this crazy world we live in it’s my opinion that the best plan is to have many avenues. Things change, that is certain and the skills we have learned are the best preparation that anyone can have. Since I live close to the Ocean that is my main route, but I have land also covered. Skills whether large of small are the one thing that can’t be taken away from you… These skills are meant to be shared with the people that will be with us in emergency situations, because the skills you share may save your life…

GenX Prepper

Another option to consider are the many types of 12 gauge adapters out there. They are pretty lightweight and compact, and will fit into any crack open style 12 gauge weather it be a single shot, over/under, or side by side. You can find them in 38 special / .357 / 9mm / 45 acp / 45LC / .410 shotgun / .380/ .40 cal / .44 mag/ 20ga shotgun. This allows for more variety in a scavenging situation without having to haul around a ton of different shooting platforms. Obviously the downside to this is the limited ammo capacity of… Read more »


An interesting read. DH and I are actually looking to buy the same handguns (or at least the same caliber) so we can easily switch if need be. The nice thing is since we are about the same size that will make finding a handgun we are both comfortable with easier. Also we both came to the conclusion separately.


I’m going to have to disagree. Last year there was no 9mm anywhere but 40 was Plentiful. Now there is no 22lr but 223 is plentiful. Last year there was no 223 but 308 could be found in spots. The point I’m trying to make is if the SHTF, ammo Will be hit and miss. Very few of us can stockpile enough ammo to last for years Living off the land. I say buy m&p, glock type handguns in the most common calibers. 9,40,45. Low cost reliable handguns. Do the same with common rifle rounds. Don’t put all your eggs… Read more »


Just get yourself a single shot 10 gauge, and a satchel with those X-caliber adapters.
Now you have an ultra-reliable firearm able to shoot every popular caliber/gauge in America.

Pat Henry

But you are seriously hampered with magazine capacity going that route, don’t you think? Those adapters are 4 pounds of metal. I would rather carry 4 pounds of ammo if I had to choose.


I should have specified: I meant as a reserve gun, a backup. The knowledge that if you find a box of 7.62, and don’t have an AK, you can still use it.

Machine Fuel

Glock is still one of the best for a SHTF scenario. I can swap slides and magazines on a 20 (10mm) and a 21 (.45). I can swap barrels to turn a .40 caliber glock into a 9mm glock. I can interchange most internals regardless of caliber (not always). And like you said, if I do stick to one caliber, I can swap mags and other parts, and I can share ammo. There are also .22lr complete slides for all Glocks. With all of these options being far cheaper than buying 2 Sigs, a Ruger and a H&K, sticking to… Read more »

greg adkins

One reason I choose a 357 revolver(obviously) if you can’t handle the 357 you can shoot 38’ no worries about compatible magazines,plus you can choose from various(companies instead of one model from one company.Choose different models for people who can’t handle the size of a larger revolver a S&W bodyguard/Ruger LCR for example.To many benefits to take into consideration especially with younger people in your group,totally outweigh the loss of capacity in the semi auto pistol.Does not mean you can’t have a couple of people(I know) who have Ruger’s in 45 Colt that are also cut to accept 45 Acp.


I see both points of view…that’s why I took a “hybrid” approach to it. Part of a local “SHTF Group” of neighbors and close friends, all with different misc cals, and all sort of stick to the “hybrid” model. I keep a Sig in 9, snubbie .38 (easy to be armed and move fast in an expeditionary situation), .22lr handguns (also have a .45, but if I’m shedding weight, separated from our group, etc., it’d be the first to go). Other than those handgun cals, I have the usual high power rifle (2 cals actually – 30.06 & 30/30 one… Read more »


I know this is an older post, but I’ve been thinking about this lately and wanted to ask thoughts on a (since this article was written) little more modern option and if it would be effective. The Glock 22 (I love my Sigs, but for this instance of compatibility), a 9mm barrel for this pistol, and a Kriss Vector Gen2 CRB with 40cal and 9mm receivers – I would also like to sling a 12ga KelTec KSG because since I have a 6’5, 220lb frame and can hold the extra 6 pounds. There are the same options for a fan… Read more »

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