Written by ILya Koshkin
Revisited in December 2017: If I could Have Only One
I revisit this topic fairly regularly, usually inspired by a conversation with someone. Somewhere through the conversation, I get asked (usually by someone who thinks that he can buy one gun and not have the urge to buy any more) “what if you could only have one gun?” At that point, I ask for boundary conditions: are we talking handgun or rifle or shotgun? Are we talking home defense? or hunting? or armed resistance to an overbearing government? Do I have my own ammo supply or do I have to count on foraging for ammo? Etc.
Also, I update my choice of “Only One” when it comes to different optics categories once a year, which I did a few days ago. Now, it is time to think about guns.
First, I am going to set the boundary conditions (I am likely to go through a couple of different sets of these in follow-up posts, so bear with me).
Imagine that the government has really limited your 2nd Amendment rights. The whole country is subject to something akin to current California gun laws exacerbated by the fact that you are only allowed to have one item of each gun type: one handgun, one rifle and one shotgun. You have to be able to use them for anything and everything you may ever want to do. You have to be able to protect your home, hunt, etc. Since these are the only guns you have, they also serve to satisfy your hobbies (if firearms and shooting happen to be your hobby, as they are for me). You are not expected to forage for ammo. Assume that the legal changes have been happening slowly enough, so you had time to stockpile enough ammo to last you for the rest of your life. The only time you have to carry your ammo is when you decide to go hunting. The rest of the time you can safely assume you are operating near your house or car, so there are means of ammo re-supply. You do not get to pick multiple sighting devices you can swap around. You can have a secondary sighting system on your gun, if you so choose, but you can not have eight different scopes pre-sighted in and ready to be swapped out in QD mounts. Since we are talking about California style gun laws, concealed carry is not a concern. My chances of getting a concealed carry license in Los Angeles are about as good as my chances of becoming a professional salsa dancer (for the record: I am big, fat and tone deaf).
Shotguns are not my field of expertise, but since I just took a shotgun class with a Remington 870, I’ll stick with that. My 870 is a very simple weapon with an upgraded recoil pad and Trijicon Front And Ghost Ring Rear Sights I installed years ago (they are a little crooked, but they don’t seem to be falling off). If I had to do it all over again, I would probably come up with some sort of a co-witnessed red dot/irons set-up, and I still might. For the time being, I will simply say that my 870 as is, with ghost ring sights and a cylinder bore, is good enough for me. I spent some time shooting slugs, buckshot and birdshot through it to know at which distances I am comfortable with it. To my great surprise, slugs are accurate enough for me to take off-hand headshots on steel at 40-50 yards and center-of-mass shots at 75-100 yards. Birdshot patterns adequately out to 20 yards and buckshot seems alright out to 35-40 yards. I am not a clay shooter, so this is good enough for me. Since I am not really a shotgun guy, I basically treat my shotgun as a very powerful short range rifle and use rifle style ghost ring sights on it.
With rifles and handguns, I have a bit more mileage and a little bit more training, so I am fairly specific with what I like and what works for me. I re-iterate: for me. YMMV
Obviously, there are many different rifle/handgun combinations that would satisfy these conditions, and practical differences between them come down to personal preference and training. I am viewing this particular set of boundary conditions as requiring maximum versatility from each weapon system and caliber. Since I removed any ammo commonality requirement out of the equation, the two calibers I converge on are 6.5 Grendel for a rifle and 10mm for a handgun.
As an aside, I have discussions like this with my friends once in a while as a thought exercise. I recall that once a while back, we were having this discussion at my house with an American-born friend of mince. Rather than go into a lengthy explanation, I walked him over to my gunsafe and explained that, me being a somewhat paranoid Jew with great appreciation of history and vivid recollections of Soviet Union where I grew up, I have thought about this before and have such a situation covered. In triplicate. And then some. I do not think he took my concerns particularly seriously (my American-born friends often don’t), but then again, he did ask the question. I did not start that conversation.
Had I been forced to rely on external ammo sources, my choices would have been different: I would have a reflex sight capable 9mm handgun and a SPR-type AR chambered for 5.56×45. However, since I get to prepare my own ammo supply, I can diverge from that a little (besides, I am well covered with those firearms as well; naturally, in triplicate; and then some)
I am still going to go with a reflex sight capable semi-automatic handgun and a AR-type rifle. However, I am going to bump up the chamberings a bit.
Let’s start with the handgun. Fairly recently, I built myself a long slide 10mm Glock, ostensibly for hunting. I originally set it up to be able to accept a variety of red dot sights using a rear sight mount form www.sight-mount.com. After some experimentation, I decided that approach works well for testing different red dots, but for my personal use, I want a set up with co-witnessed red dot/iron sight arrangement. So I have a second slide for it, milled for DOCTER sight III, Dot size 3.5moa. In principle, if I lived in a civilized state, I would have simply bought a Glock 40 MOS and be done with it. However, Gen 4 Glocks are not for sale in California (for reasons sufficiently idiotic I’d rather not get into them). When I decided to build this gun, I headed over to the store, and bought Glock 21SF chambered for 45ACP. As un-American as it sounds, I no longer shoot 45 (I sold my last 45, a Sig P220 a while back), so I took the whole slide assembly off and sold it on Gunbroker. Then, I took most of the internal parts from the frame and removed them, since I wanted to build this gun exactly the way I like it. Then I headed off to Lone Wolf and GlockTriggers.com websites and did some shopping: 6” long solid top slide, 6” long barrel, and the rest of the parts I needed to build this thing. The milled slide was done exceedingly well by a friend of mine who specializes on custom slide mods like this. I highly recommend his work. The trigger is Haley Skimmer which, to me, remains the best Glock trigger on the market. The iron sights I am going to put on are from Suarez International and they are still on their way. WHat I am going for here is lower 1/3 co-witnessing.

Longslide 10mm Glock with Doctersight III. 6″ barrel and heavy slide do an excellent job of taming recoil
I am not a particularly good handgun shot, but I usually hit what I am aiming at. It also helps that I actually practice. With typical iron sights, longer shots become a bit of an issue due to the need for holdover. Even with a comparatively narrow front sight and a long sighting radius, proper holdover is hard for me. Well, that is where a reflex sight really makes a difference. Since everything around the aiming point is open, it is much easier for me to do simple trajectory compensation. Don’t get me wrong, I do not advocate taking unnecessary long distance shots with a handgun. However, it is nice to have that capability and it is a good idea to practice these shots even if you will never take them in the field. My 25 yard shooting seems to have gotten a fair bit better ever since I started practicing at 100 yards with my 10mm. In terms of terminal ballistics, a full power 200gr load out of a 6” barrel has about as much pop at 100 yards as 40S&W has at the muzzle. It is not the equal of a proper longarm, but it is nothing to scoff at either. I am also planning to experiment a little with ENDO Tactical TSA-G adapter and forearm brace. Perhaps that will give me more stability for longer shots.
I originally built the 10mm as a hunting semi-auto, but once I got it finished up, I realized that I can still draw it pretty quickly and the recoil of the full house 10mm rounds is nicely soaked up by the long and heavy slide. Another useful characteristic is that it shoots 40S&W just fine without any modifications: same magazines and everything. That adds versatility (and I also have a 357Sig barrel for it).
In practical terms, I am a bit faster with the 9mm, but since I am requiring maximum versatility with this set-up, 10mm it is. A revolver in a larger caliber would undoubtedly be a better hunting handgun, but with slower recovery and slower reloading it would be not be nearly as good for defensive use. 10mm is neatly capable of both uses and, keep in mind that with a 6” barrel I get pretty good velocities out of it. This is pretty much the best semi-auto compromise I could think of between hunting, plinking and defensive use.
Anyhow, with the handgun selection out of the way, let’s talk about the rifle. A couple of things were apparent from the start. Since this rifle has to cover home defense situations, this requirement can not be compromised a whole lot. For example, for long range target practice that I enjoy and for hunting I might want to pick a fairly peppy cartridge, but for home defense situations, I want to keep rifle weight and recoil down while maintaining the ability to make quick follow-up shots. That basically narrows the choice of the rifle and of the caliber down to intermediate cartridges: 7.62×39, 300AAC Blackout, 6.8SPC, 6.5 Grendel and a few others. All of them work equally well for home defense situations, with a suppressed Blackout likely taking the cake. However, in my post apocalyptic California nightmare suppressors are likely going to be illegal anyway. For hunting purposes, all of these work about equally well at distances at which I am likely to take a shot. However, for target shooting, the Grendel is an obvious choice (I happen to own rifles in all of these calibers aside from the 6.8SPC, so I’ve exercised them pretty well). Now, many people I know prefer a larger frame AR or similar gun chambered for 308Win or some other similarly sixed or bigger cartridge. I think they are wrong and these guns give up too much, in terms of shot recovery, weight (with ammo), handling and muzzle blast. Then again, to each his own.
The rifle type would likely be either an AR or AK variant of some sort. I am very partial to bullpup rifles, so I’ve got my sights set one exploring Desert Tech’s MDR, and Keltec’s RDB-C which forgoes the pistol grip (and is weirdly comfortable that way while complying to California’s lunatic laws). It is on my list of guns to get and test once it becomes available, but as of now, I stick with the AR platform. For most uses there isn’t really any practical reliability difference between AK and AR, but a well built AR is usually more accurate and can be configured for the Grendel. My version of this gun, sports a medium weight 18” barrel that is accurate enough to take me out to 800-900 yards in a pinch, while keeping the weight manageable for everything else. I took this rifle hunting with me and, while I am not a huge fan of humping up and down the hill out of general principle, the rifle weight was manageable. That is where I think it has a pretty notable advantage over large frame ARs. I have a similarly configured AR10 chambered for 308Win, and it is notably less maneuverable. It is not just the weight, but also the balance. That balance is really the reason I am so interested in bullpup rifles. My precision bolt gun is a bullpup Desert Tech SRS and it handles far better than a gun that weight ever should.
In terms of terminal ballistics, despite all sorts of fanboy commentary out there, the Grendel is not a match to 308 and larger cartridges, but with reasonable shot placement it is sufficient for typical big game in North America: pigs, deer, etc. Once distances start opening up, 6.5 Grendel is closer to 308Win than it is to 5.56.
Let look at drop velocity and energy for three bullets that I regularly shoot: 77gr in 5.56, 123gr in 6.5 Grendel, 175gr 308Win. I am going to look at drop in mrad, velocity in fps and energy ft-lbs. All data is from Shooter app on my phone. I am assuming 2000ft altitude, 60F, 50% humidity (which is very different from where I live, but clsoe enouhg for everyone else).
I am assuming that the 308 has a 16” barrel, while the other cartridges have 18” barrel. This keeps overall length of the gun about the same, although in terms of weight the large frame AR will likely still be a bit heavier. I am also assuming that the velocities are 2700fps for 5.56, 2525 for 6.5 Grendel and 2500 for the 308Win. These are the velocities I have actually chrono’ed. All barrels vary, so yours might be doing something different. Personally, I think I am being a little generous to the 308 since most 16” barrels I have seen were slower, but I like round numbers.
Also, keep in mind that I am only looking at one particular bullet for each caliber and these are not really hunting bullets. However, I like looking at SMKs for cross-caliber consistency reasons. With 308Win, I need to explore a little bit how well modern 155gr bullets do out of a 16” barrel. They are fairly efficient and go faster.
Drop, mrad
Distance, yards | 5.56:
77gr SMK @ 2700fps |
6.5 Grendel:
123gr SMK @ 2525 fps |
308Win:
175gr SMK @ 2500fps |
200 | 0 | 0 | 0 |
300 | 0.8 | 0.8 | 0.9 |
400 | 1.7 | 1.8 | 1.9 |
500 | 2.8 | 2.9 | 3 |
600 | 4.1 | 4.1 | 4.4 |
700 | 5.7 | 5.5 | 5.8 |
800 | 7.5 | 7.0 | 7.5 |
900 | 9.6 | 8.8 | 9.4 |
1000 | 12.2 | 10.7 | 11.6 |
Velocity, fps
Distance, yards | 5.56:
77gr SMK @ 2700fps |
6.5 Grendel:
123gr SMK @ 2525 fps |
308Win:
175gr SMK @ 2500fps |
200 | 2269 | 2217 | 2174 |
300 | 2069 | 2073 | 2021 |
400 | 1879 | 1933 | 1873 |
500 | 1698 | 1798 | 1731 |
600 | 1525 | 1668 | 1594 |
700 | 1360 | 1541 | 1462 |
800 | 1206 | 1420 | 1335 |
900 | 1078 | 1303 | 1215 |
1000 | 1017 | 1192 | 1106 |
Energy, ft-lbs
Distance, yards | 5.56:
77gr SMK @ 2700fps |
6.5 Grendel:
123gr SMK @ 2525 fps |
308Win:
175gr SMK @ 2500fps |
200 | 880 | 1343 | 1837 |
300 | 732 | 1173 | 1587 |
400 | 603 | 1020 | 1363 |
500 | 493 | 883 | 1164 |
600 | 398 | 760 | 987 |
700 | 316 | 649 | 831 |
800 | 249 | 550 | 693 |
900 | 199 | 464 | 574 |
1000 | 177 | 388 | 476 |
Simply looking at the numbers a few things are apparent. In terms of energy and stopping power, 308WIn is undoubtedly the better cartridge. However, in this case, I am mostly preoccupied with good enough within a certain weight/size envelope. Otherwise, there is no limit to how far you can go. 300 WinMag is better than 308Win, and 338LM is better than 300WM and so on.
Looking at the energy, the 6.5 Grendel should be good enough for me to use for hunting out to 400 yards, which is further than I have any business shooting at an anumal from field positions. Hunting is where 5.56 is obviously very marginal. 308Win would give me extra couple of hundred yeards over the Grendel in terms of energy, but to be honest, if I ever take a shot at an animal at 600 yards, it will not be with either one of these cartridges.
For target shooting, with these fairly short barrels, the Grendel is actually a little flatter than the 308Win and drifts a little less (this would change with longer barrels as 308Win benefits mroe from a longer tube).
There are of course other cartridges to look at that are in between like the 6.5Creedmoor and others, but after looking at a bunch I have basically concluded that for me, 6.5 Grendel is what I judge to be good enough. YMMV.
As far as the actual rifle goes, to each his own. The bulk of my training has been with an AR paltform, so I choose to stick with that. Since I tend to follow what I preach, I own an AR-15 chambered for the 6.5 Grendel, built on VC Defense upper and lower receivers, BHW 18” barrel, 15” Lancer carbon fiber handguard and, CA-compliant FRS-15 stock (which is fugly, but comfortable enough). I have a rather excellent Geissele DMR trigger in that gun, and I often use it to test scopes since despite reasonaby light weight (7lbs without optics) it is very shootable and sufficiently accurate with both factory ammo and handloads.
Since in my scenario this is a rifle that might be used for self defense, I must have the ability to run it 1x or similar with a very visible aiming point. If I could have only one sighting system for it, it would have a Tangent Theta TT315M on it with a compact red dot sight mounted at a 45 degree angle. Another interesting scope option that is even lighter than TT315M is Leupold’s new Mark 5HD 3.6-18×44 although I have some issues with the reticle options there. As it is right now, I am messing with Elcan Spectre TR on it. Spectre TR gives 1x, 3x and 9x and the ability to switch between them extremely rapidly. I took it to a carbine class and at 1x it functions virtually like a red dot sight. Switching magnifications with Spectre TR is faster than with any other riflescope I have seen to date. However, at 9x, while very serviceable, it is not a match to a proper precision scope at distance. On the other, it is not too shabby either. The reticle is set-up with BDC holds for 7.62×51 and they work exceedingly well for the Grendel. Also, if you are looking for a riflescope that is sturdy enough to club baby seals with any of the Elcans should be on your list.

Elcan Spectre TR on a similar AR-15 (this is not on my Grendel, but this is the only picture I can find right now).
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