Getting enough practice to enable very rapid ejection of the spent shells followed by reloading to get back into the fight would be one answer. I've seen videos of a Bond Arms shooter who reloaded his derringer faster than I can drop a magazine and reload my Shield. But, he is certainly the big exception to this rule. I wonder how many rounds that person sent downrange during his many practice sessions to be able to do that. Most of us don't have the time, opportunity, inclination or money to get to that level of expertise. I'm more concerned about the ordinary person who is carrying a weapon for self defense and does not have the time or interest to become an expert. For most of us, two shots with a derringer and the game changes if the bad guy, or guys, are still a threat.
Another option is to have another gun. Many experienced individuals advocate carrying two guns. They have various reasons, most of which are really good. I sometimes follow their advice, but not always. I'm not in law enforcement and don't expect to get into situations where two guns may be necessary, and, frankly, it is a pain to carry more than one gun most of the time. However, when going to towns, cities and places where I think the likelihood of danger is higher, I have carried two guns and the Bond Arms is an excellent choice for a second gun. I don't call it a "backup" gun because I may carry it in a position in which, circumstances depending, it might actually become the main, or first gun I resort to. I may have an SR9c riding on my strong side, with the Patriot at the appendix or cross-draw position because sitting in my car or at a restaurant for example the Patriot will be much easier to draw, and far less obvious to get my hand on if I need to do so without drawing attention.
Not all situations are the same, and it might well be the case in some of them that one can fire off two rounds, then have the time and opportunity to reload. Not all incidents happen and are over within a couple of seconds, though most street incidents do, according to many law enforcement speakers I have heard. Even so, these quick-fire actions do not always revolve around a fast draw contest. Often, if one is aware of what is happening as we should be, one knows that the situation is turning bad and has time to bring a gun into play first and get off an effective well-aimed shot.
There are no hard and fast rules except to carry your gun legally all of the time. You will have to make the call about which gun or guns you are most comfortable with. Away from home I have carried only the Patriot with two rounds in one of Paul's mag carriers on my belt, and two more in my pocket, just in case. I didn't feel under gunned or particularly vulnerable, but I don't live in a very dangerous place, so I think that was appropriate.
Continuing this line of thought, it is my opinion that the Patriot is an excellent choice for what I call an "around the house gun". I am a believer in the philosophy that if one decides to go to the trouble to carry, one should carry whenever possible, and that means around the house as well as around town. Now, I live in a pretty peaceful place. We've had the rare assault, break-ins, and a couple of years ago, one drunk young man stabbed another, killing him. Is this a crime wave? No. But, I also know that unbalanced individuals have, and will continue to go about killing people at random, robbing civilians on the street for drug money, or for more gas to get out of town. The reasons people kill other people are many and some are not easy to believe until you understand that some individuals just don't care if they kill another person. They don't think or feel as most of us do, and they make up a certain percentage of our population. It's not out of the realm of possibility that a couple of meth-heads, looking for money or to satisfy their strange logic, will crash into someone's house at night and go to work. That is not likely to happen where I live, but it is not impossible either.
It is very unlikely that I will be involved in a traffic crash, but I still wear my seat belt, make sure my airbag systems work and keep my car insurance up to date. I also carry a gun for much the same reason.
So, around the house, where we spend much time, is a good place to carry. Many people, perhaps most, who have a gun around the house keep it somewhere not on their person. This makes little sense to me. I'm in the kitchen. My gun is in a drawer in the bedroom. Some idiots crash into my house, waving guns, knives, baseball bats and decide to quickly take care of me and my wife and get what they want. I'm probably not going to make it back to the bedroom, retrieve my gun and start shooting. I'm probably going to be dead first. This is where the Bond Arms can come into it's own around the house.
If I shoot one of these individuals with a load of five 00 Buck pellets accompanied buy one of the loudest explosions they have ever heard going off in their face, the other(s) will likely run. If not, I've got another round to shoot again and increase my odds of getting to the other gun. While some might note that this situation is far from ideal (ideal would be to have a fully loaded semi-automatic 12-gauge loaded with 00 buck at hand) it is certainly better than not having a gun at all.
The Patriot being an easily carried, comfortable and concealable gun with a devastating punch is an ideal choice for an around the house, and out in the yard gun.
It is also a good choice to take along in the car, stowed in an accessible location, in case some idiot confronts you with deadly force while you are seated. A situation like that will be at very close range where the .410 barrels come into their effective best.
The not so good: Hammer and trigger. Derringers classically are made as single action, hammer fired weapons. Firearms technology has moved on since those early days and we now have reliable, easy to use mechanisms that are superior to single-action, hammer-fired pistols. There is nothing wrong with the early designs. They are time-tested and extremely reliable, which can not always be said about some of the newer technologies. However, in a self defense role, when speed and ease of actuation is at a premium, they are not the best choice available.
I have had conversations with Bond Arms about the hammer on their guns. I have also had conversations with other Bond Arms users and with some very knowledgeable people who are critical of the pistol for that reason. Simply put, you must cock the hammer before the gun will fire. Being that it is really not a good idea to carry a cocked single action pistol, even with the manual safety engaged, in a holster, especially a concealed carry holster, it is necessary to draw, then cock the hammer before firing the gun. This should not be an issue for a self defense gun. There are pistols with hammers that are easily and quickly cocked by the average person. The Bond Arms derringers are not among those. These hammers are controlled by springs that are strong and make them difficult to cock with one hand.
Let me emphasize here that this criticism, that the Bond Arms pistols' hammers are hard to cock one-handed is directed solely toward the pistol's use as a concealed carry self defense handgun. At this point, I have personally cocked and re-cocked my Patriot's hammer hundreds of times, perhaps as much as a thousand, in order to see if the action will smooth out and become easier. It did improve after the first 100 cycles or so, but beyond that it is essentially the same: difficult. I am over seventy years old, but I am also 6' 4", 212 pounds and in pretty good shape for an old guy. I have trouble cocking the pistol with one hand, especially after the first five or six times in a session. Of course, it is easy to cock the pistol with my non-shooting hand. When I lift my cover garment and draw the pistol my left hand is in a perfect position to fan the heel of that hand across the hammer, quickly putting it into the cocked position. This almost always works. However, as you know, you might be in a situation in which your off-hand isn't available: you are shielding someone, or moving someone out of the way. Your off-hand is injured or caught or you are using it to protect yourself from a close up assault. In these instances you must be able to draw, cock and quickly fire. This isn't always possible with the Bond Arms since the hammer is stiff and difficult to operate with one hand.