The “2 is 1” Rule and How It Applies to Your Arsenal

You’ll often hear the adage “two is one, one is none” whenever discussing emergency preparedness. And there is a good reason for that. It’s a statement that represents the need to have a backup plan for when things don’t work out. Coined by the Navy SEALs to express that having two plans is equivalent to having one plan and one plan is no plan at all, the saying applies to almost every aspect of being prepared. If that’s the case, then how does this apply to your arsenal? Do you need to carry two pistols to have one? Should you keep a backup rifle in your pack in case your primary rifle goes down? I think we can all agree that both of those options are unrealistic in most scenarios (unless you’re on team backup gun, which I can appreciate). So, is there a way to meet the “2 is 1” requirement without going overboard with your firearms? 

Dual Wielding Pistols 

The “2 is 1” rule sounds great until you start thinking about your concealed carry or duty carry pistol. Do you really need to carry two handguns in order to have “one”? Personally, I carry a pistol every single day. But only one. And in all honesty, even just carrying that one pistol can be a pain at times. Some people carry a backup gun, and they easily accomplish the goal of “2 is 1”. Police detectives have been known to carry backup guns on their ankles or in their pockets, depending on their situation. But I would guess that the majority of people who carry a gun daily, whether civilian or law enforcement, generally only carry one pistol. That being said, can you still meet some of the criteria of the “2 is 1” rule without a backup gun? I think so. 

The first thing you can do to compromise on this rule is carry a spare magazine. Magazines are one of the most common reasons you’ll experience a malfunction in a firearm, especially in a gun that doesn’t have a long track record of reliability or years of development. If you apply the “2 is 1” rule to your magazine, well, the one in your pistol is “none,” and the spare mag you’re carrying is “one.” I carry a spare magazine with my pistol, but not because I think I’ll need the additional rounds for a self-defense scenario. I carry it in case there is a malfunction that isn’t fixed by “tap, rack.” This makes the spare magazine a great way to get closer to the “2 is 1” requirement without carrying a second pistol. 

Let’s say things have gotten dicey, and self-defense is becoming a higher priority based on a dangerous environment. You might only have one handgun, and it might be the only one you can get for a long time. And perhaps affordability was the reason why you couldn’t buy a duplicate of your pistol for “just in case” scenarios. Luckily, modern pistols from quality manufacturers tend to be pretty durable and reliable. Glock, Smith & Wesson, Sig Sauer, Heckler & Koch, CZ, and Walther are among many manufacturers I could easily recommend that fit the aforementioned criteria. Even the best-made pistol has small parts that can break or wear out over time. Luckily, most manufacturers offer small parts to the commercial market. And I would argue that being able to replace any of the most likely parts to break almost equates to having a number “2” gun in your arsenal, especially since the parts you need to have spares for are usually pretty affordable. That would include an extractor, ejector, slide stop spring, connector springs, firing pin, and, depending on round count, a recoil spring/recoil spring assembly. If you stock up on these parts, you’ll likely be able to keep a handgun up and running for years on end. 

Call of Duty Double Rifle Loadout 

Rifles can make the “2 is 1” rule even trickier, as carrying two rifles is something usually reserved for AAA gaming titles. Yes, there are some examples of military service members with particular skill sets carrying multiple rifles for very specific necessities. But that’s not me and probably not 99.9% of anyone else, either. Let’s be honest: one rifle can be too heavy on its own, depending on how you set it up, let alone two rifles. So, if you ever find yourself in a situation where you need a rifle, how do you still abide by the “2 is 1” rule? 

For starters, the same spare magazine argument discussed with handguns also applies to rifles. Having some backup magazines with you is a good idea if we’re talking about the need for a rifle during an emergency. Small parts for repairs and maintenance are another good approach that overlaps with the pistol discussion. Extractors, ejectors, small springs, firing pins, bolts, and more can wear out and require replacement over time. But what about options that are specific to rifles? Even better, what about options that are specific to the AR-15? 

Now, this applies to any rifle platform, but I will say that the AR-15 is more optimized for this concept. Rifles give you range and accuracy at range, which requires a sighting system. These days, red dot sights, prism optics, and rifle scopes are common on personal defense weapons, along with iron sights. Since carrying two rifles to have one is not practical, making sure you can use your one rifle efficiently is imperative. By applying the “2 is 1” rule to your sighting system, you can ensure that the range and accuracy of your rifle system remain useful in case of breakage. For this reason, I would like to have at least two sighting systems on my defensive rifles. Whether that’s a red dot with some backup iron sights or a rifle scope with an offset red dot, as long as I have at minimum two sighting systems, I have one, and that means I can aim properly. 

Another way to partially achieve the “2 is 1” rule, specifically when discussing AR-15s, is by adding a couple of key components to your pack. One component would be a spare BCG (bolt carrier group). Not always, but quite often, when you run into reliability issues regarding AR-15s, they can be solved by swapping the bolt carrier group. By dropping in a different, complete BCG, you are “replacing” the firing pin, extractor, extractor spring, ejector, ejector spring, bolt, and gas rings. Some of them have shorter parts service lives than other components of your rifle. The bolt carrier group and barrel are often referred to as the “heart and soul” of the rifle because of how important they are for reliable function. In a way, by carrying a spare BCG, you pretty much have the most important part of another rifle. So, almost 2 is almost 1? 

An often-overlooked option that is one of the best features of the AR-15 platform is the ability to swap upper receivers on your singular lower. This is something that is more common or likely to be seen in the military rather than the carrying of two complete rifles. Why take on the additional weight if you only need one lower receiver to run either upper? Now, although you can’t actually count a secondary complete upper receiver as a number “2” gun, it is pretty much as close as you can get. It also allows you to add versatility by having a different barrel length or optics setup based on what you might need it for. Is this a practical approach for the average prepared citizen? Probably not, but it is an option and one that makes way more sense to me than carrying an extra rifle. 

In Conclusion 

The “2 is 1” rule makes a lot of sense in most areas of preparedness. Having two generators is a good idea in case one breaks down. Having access to two water sources in case one becomes compromised is a good deal. Now, when you apply it to your defensive firearms, you can at least approach it in a way that doesn’t require going full Tomb Raider. That being said, if you decide that carrying two HK USP Match pistols is the right thing to do, I am definitely not the guy who is going to stop you. 

--Magic Prepper