‘Light rifle’ is a term we don’t hear very often these days. We have the “assault rifle,” the battle rifle, and the infantry automatic rifle, but the wee light rifle as a concept doesn’t get discussed much. That’s likely because there is only one really worth mentioning, the M1 Carbine. The M1 Carbine won the light rifle competition in 1942 and went on to serve its country around the world. There hasn’t been much mention of light rifles as a genre ever since, but I think we might be seeing a revitalization of the concept of the light rifle.
What is a Light Rifle?
A light rifle, as epitomized by the M1 Carbine, isn’t a pistol-caliber carbine or an intermediate rifle. It fires a real rifle caliber between your typical pistol cartridge and an intermediate rifle round. The .30 Carbine is a perfect light rifle round and exemplifies the concept. In the modern era, no one is taking advantage of the cool .30 Carbine round except for companies still producing M1 Carbine replicas.
A light rifle should be relatively lightweight and compact, even in an era of modern AR carbines. It’s designed to be light, handy, and easily used in and out of vehicles. Something you can toss over your shoulder and forget about. These guns should be semi-automatic with detachable magazines and modern ammo capacities.
Its effective range is about 300 yards max, but it’s probably best used within 200 yards. Typically, we want flat-shooting performance out to 150 yards. In a perfect world without the hated NFA, we wouldn’t be limited to 16-inch barrels either, so for that reason, a light rifle could have a barrel of around 10 inches, but not one longer than 16 inches. Maybe we’re not only talking about light rifles here, but also large pistols…that’s for you to decide.
The Modern Light Rifle Cartridge
With all the above in mind, what exactly does a modern light rifle look like? A lot of the light rifle’s use case relies on the cartridge it fires. In 2024 one of the best light rifle cartridges would arguably be the 5.7x28mm. The .30 Carbine and M1 Carbine as a whole was designed to arm troops who weren’t on the front lines. It was smaller and lighter than an M1 Garand, but offered a lot more punch than a M1911.
In the 1990s, NATO wanted a personal defense weapon, specifically a platform that functioned like the M1 Carbine. It armed noncombat troops with something better than a pistol but lighter than a rifle. The program resulted in the FN P90 and HK MP7. The P90 seemed to be the more successful weapon, and the 5.7x28mm cartridge has gained a fair bit of popularity ever since.
The 5.7x28mm round is roughly the length of a large pistol round. It’s small enough to fit inside a pistol grip and uses a spitzer-type projectile and a bottlenecked cartridge. From a rifle, the round can reach 200 yards with a reasonably flat trajectory. It also has excellent penetration up close. The little 5.7 bullet won’t be confused for a medium game cartridge, but it’s been effective on coyotes and even small hogs.
The 5.7x28mm cartridge isn’t the only option, though. There’s also 4.6x30mm, although I think only two guns on the civilian market use it: the pricey Tommy Built TP7 and the CMMG FourSix AR. One could argue the 10mm, in certain loads, isn’t far from the .30 Carbine.
The 10mm round in a 16-inch barrel can get a 180-grain Buffalo Bore round moving at up to 1,600 to 1700 feet per second. That’s not far from the 110-grain .30 Carbine round at 1,990 feet per second. The little 10mm might be this realm’s most common ammo option.
The New Trend
This idea has been bouncing around in my head for quite some time. What spurred me to explore it further was the release of the KelTec SUB2000 in 5.7x28mm and the Ruger LC Carbine in 10mm Auto. Both guns fit the concept of a modern light rifle well. Both are lightweight, compact, and capable of reaching 200 yards or so.
Of course, they aren’t the only examples. There’s the semi-automatic FN PS90 with its bullpup format. There are numerous ARs from CMMG in all sizes and in calibers like 5.7x28mm, 10mm, and the previously mentioned 4.6x30mm. The M1 Carbine could still fill the role as well. I think having a folding stock, or in KelTec’s case, an entire folding gun, makes the gun more adept than light rifles.
The purpose of such a gun in the civilian context is simple. It’s lightweight, easy to store, and easy to carry. It offers more range than your typical pistol caliber carbine. The rounds tend to have better penetration and overall ballistics. It could be a camp rifle or truck gun. It would also be a great tool for someone who is recoil-sensitive.
Outside of the 10mm rifles, the 5.7 and 4.6 rounds have near rimfire levels of recoil with centerfire reliability. The .30 Carbine tends to be a fairly soft shooter as well. The 10mm rifles aren’t bad, depending on the configuration. The CMMG Banshee series with their radial delayed blowback systems is very soft-shooting, but anything straight blowback can have 5.56-like recoil.
The light rifle concept has little if any military application these days. It seems to be purely a civilian concept.
A Worthwhile Cause?
Like many firearms concepts, the light rifle is held back by cost. The guns and ammo are more expensive, and the concept’s benefits aren’t great enough to warrant the additional cost for most people. Things like the KelTec SUB2000 in 5.7 offer a lower barrier to entry, but the ammo price can still be a hassle.
It might be a silly little idea, but if I can get ahold of a SUB2000 in 5.7x28mm, you can look forward (or not) to me testing the concept and seeing if it holds water…or if I’m just bloviating about something silly.
I’ll take KelTec or Ruger in .30 Luger.
Or 7.62 Tok if it would fit – don’t know if it is longer than 10mm.
Seems like the .30 cal bullets would give flat shooting and good penetration.
357 Sig might work but don’t know if a carbine barrel would add significantly to the velocity.
9mm doesn’t benefit from carbine barrels like a 357 Magnum does.
But a KeltTec carbine wins for sheer handiness or storage and use.
http://ballisticsbytheinch.com/357sig.html Sig does fine I would probably call it around 10 inches but whatever works. 9…… I would like to see some of the 50-68 grain loadings chronoed but yeah not a huge jump for anything I have seen. I think tok is a tenth of an inch longer than 10 so might be workable depending on mag/grip thickness and construction.
The problem is no one makes carbines for it. I think people tried to, and they had problems with it.
I had found this guy before. He says blow back won’t work:
Our Sig builds are gas operated and take a customized 6.8 SPC BCG and custom Gas system. These are NOT blow back barrels that can be swapped on to your 9mm lower. This makes the build much more expensive than just a barrel swap. Lead times are now down to 1-2 months!!!!
There is a reason you can’t find 357 Sig Blow Back barrels any more: They Blow Up! They cause case head separations and can damage you and your upper.
https://thearguy.com/news/357-sig-barrels-and-uppers
Neat, slightly disheartening but goes to show there is always more to learn. So 40 is probably the upper limit for affordable options.
I like where you’re going. I really like the idea of exploring the LC carbine or something similar as approaching a “real” rifle, like the .30 carbine. Not interested in exploring a Sub2000 in 5.7×28 or a Banshee in 4.6, as those rounds are just too tiny and underpowered.
As a fan of 10mm, as perhaps the biggest fan of 10mm, I suggest you contact Ruger and ask them for a couple of LC’s, one in 10mm and one in .45. I am VERY curious about the prospect of a 10mm at full power out of a 16″ barrel, shooting something like the Buffalo Bore 155-grain TAC-XP (my handgun carry load). That Barnes bullet is always an outstanding performer, and the weight is darn near the same as a .308; out of a 16″ barrel it should exceed 1700 fps. That’s 1,000 ft/lbs of energy, about on par with an AR-15, but with a massive bullet. Wish it was over 2,000 fps though, that’s long been the threshold for creating massive rifle-style stretch cavities and damage. So how about the DoubleTap 125-grain TAC-XP? That little bastard is rated at 1600 fps out of a 4.6 inch barrel, I bet it’ll surpass 2,000 out of the LC Carbine. That’d be over 1100 ft/lbs of energy (more than some AR15 .223 loads), ammo-piercing velocity, and a comparatively massive bullet (4x the weight of some .223 loads).
My interest in the .45 carbine is in its subsonic capability and the potential of +P and .45 Super/.450 SMC ammo. For home defense, the LC Carbine .45 seems perfect — it should throw a .45 HST +P at somewhere around 1050-1100 fps, so with a suppressor you’re talking about the biggest, heaviest, most destructive piece of lead you can fire at hearing-safe levels in your house. You’d have to go to .458 SOCOM to get a heavier bullet than that, and then you’re only getting 9 rounds in a mag, whereas with .45 you can get 26 or 30 or more rounds in a mag. So that covers home defense, probably better than the 10mm does because it’s so loud, but for light rifle duty you’ll want something like the DoubleTap .45 +P 160-grain TAC-XP, should do something close to 1500 fps from the carbine, for around 800 ft/lbs of energy. Not too shabby. And the big question is .45 Super or .450 SMC – can the LC handle it? If so, that brings 10mm levels of power to the .45 round. If something like the Underwood 185-grain .45 Super can hit 1600+ fps, that’d be over 900 ft/lbs on the target. Or DoubleTap’s 160-grain copper bullet, that exceeds 1400 fps from a 6″ barrel, could it surpass 1700 fps from the carbine (for over 1,000 ft/lbs). That’d be some serious smack.
Having one gun that can deliver the ultimate subsonic punch, while simultaneously being able to deliver AR15 levels of energy on a target just by swapping out a 30-round magazine? That’d be one versatile light rifle.
Dammit, I forgot that Liberty stuff. Liberty Overwatch in 10mm has been tested at 2650 fps from an LC Carbine. That’s real rifle velocity, although it’s only 70 grains. Should make a nasty wound, although penetration might suffer.
It’s 105 grains in .45. Might hit near 2,000 fps from a carbine. That’d be close to 1,000 ft/lbs, and armor-piercing velocity, so definitely worth testing.
Older and somewhat dated data but don’t have any problem believing the liberty claimed velocity http://ballisticsbytheinch.com/10mm.html
I live in a very rural area. PCCs and the like aren’t real popular, but I can see why they would be in the suburbs or urban areas. There’s a stigma out here against a healthy male who can’t handle a medium bore centerfire rifle or 12g shotgun, it’s part of the culture, though the younger generation has embraced the 5.56mm and 300BO ARs with gusto, more so than the previous one did with the Mini-14s and 30s. There’s a lot of new caliber resistance since most gun owners have inherited one or (more likely) several guns and see little reason to stray into 21st century wonder chamberings. Country folk do buy a lot of guns, they just rarely follow the latest and greatest marketing trends. My last new purchase was a Colt Python 6″, not exactly a cutting edge form factor.
Sweet spot, barrel-wise, for most “regular” pistol cartridges is right around 8 inches. 9mm, .45, .40, etc. Move up to revolver magnums and it’s conveniently 16″. 10mm seems to fall in the middle somewhere, same with the 5.7 and the other smallbores in this class (4.6, .22WMR, .22TCM, etc). Let us buy FA again and I’d be right in line for an AR57 with those funky P90 mags plus a Kel-Tec CP33 and I’d test the heat resistance of that sucker. Or, even better, a modern remake of the American 180. But as semi autos they’re not terribly interesting when I can just get a “regular” centerfire rifle for just a little more weight and recoil.
Stigma is a a funny thing. It may keep rural gun owners away from various incarnations of wannabe smg options and in decades past pistols. For the built up areas full sized rifles are often ignored because of the hassle of finding places to shoot them but realistically the stigma is on owning guns at all so those that do tend to more go along the fuck it I will own and use it just to piss you off mindset. Personally I want to see more development in this in between of large pistol but not quite intermediate rifle as I think many of the lessons learned can transfer to other classes of firearms/powder/bullet construction etc
I built an AR pistol in 350 Legend with a 10.5″ barrel. If the NFA nonsense ever goes away, I may put a stock on it, but it does well with a padded buffer tube and an elastic sling from Warrior Poet Society, shooting from the cheek like Rhett Neumayer. It has a bit more range than the Contender in 357 Max and a lot more capacity (sorry Ol’ Bess, but it just does).
It’s tough to beat something like the Q Honey Badger or a generic equivalent. An 11.3in 6.8 SPC gets the job done for me. A pistol caliber might make sense when you have a handgun in the same caliber. Paul Harrell has a video on this. He had an M1 Carbine along with a Ruger .30 Carbine revolver. Then there’s the 5.7, .44 mag, and 9mm.
Hard to beat cheap and available 9mm, 22lr 40sw (previously) and lever action covers most of the rimmed magnum rounds. While a lot of cartridges have a lot of interesting potential the combination of laws, inertia, and availability/popularity will likely keep things fairly close to the status quo for a long while.
Hey Travis, big fan of all your articles been following you for 3 years now I read everything I come across by you. We have similar interest. I built a 6.8 Spc 12.5 barrel on a cross machine and tool ambidextrous receiver set which just happens to be one of the lightest AR I’ve built which is only five I found my biggest enemy in building is weight. Most of my guns are coming in 6.6lbs naked. getting a gun to be 6 pounds with an optic and mag is a real treat maybe you could do a little write up on the 6.8 SPC thanks John
Some hotter 357mag loads approach 2000fps out of 16″ barrels.
I’ve often wondered why a 357 mag semi-auto ‘light rifle’/carbine hasn’t been attempted. Ruger’s Deerstalker appears to have a cult following.
Absent that, I’d take a slim and handy 357 take-down lever gun.