It’s somewhat ironic that the cartridge the U. S. Army decided to adopt in 1964 as its official military round, the 5.56×45 M193, was considered in the civilian world as nothing more than a varmint cartridge. I’m talking of course about Remington’s decision that same year to adopt the cartridge. Thus the civilian .223 Rem. came to be. Remington immediately began chambering for the cartridge in its Model 700 bolt action rifle, and other companies quickly followed suit.
With the nominal load being a 55 grain bullet at 3240 fps and 1280 ft. lbs. of muzzle energy, it was a pipsqueak compared to the 7.62×51 NATO (.308 Win.) it would replace. The gun writers of the day were quick to point out that the .223 was not suitable for hunting deer size game. With few exceptions the guns chambered for the .223 were bolt actions fitted with barrels having a rifling twists of 1-12”, which would stabilize bullets up to 60 grains or so in weight, depending on specific length.
A year before the .223 appeared on the market, Colt was already selling a civilian, semi-auto version of the Army’s M-16 battle rifle calling it the AR-15. It was the start of what would within 20 years become a phenomenon unlike the shooting world had never before seen.
With the number of owners now in the millions, the enthusiasm level among many is such that they are bound and determined to use their beloved ARs on game. A good idea? Well, let’s look at the figures. The nominal ballistics for the .223 haven’t changed; they’re still 3240 fps for a 55 grain bullet with 1280 ft. lbs. of muzzle energy. But that’s out of a 24” test barrel. With the average AR barrel being around 18”, those figures drop to below 3000 fps, which means less than 1100 ft. lbs. of muzzle energy. Now there is a long held belief that 1200 ft. lbs. of delivered energy is required to reliable put down a deer or antelope. If you ascribe to that premise, the typical AR doesn’t have enough…power, if you will, to dispatch a deer at the muzzle, let alone 100 yards!
So what’s changed, if anything? It’s the bullets. Not that a simple change in bullet weight or construction can affect ballistic performance enough to suddenly transform a varmint cartridge into a big game cartridge, but it can certainly help. The military has long since gone to heavier bullet weights, and sporting ammo and component bullet manufacturers have done the same. The faster 1-7” and 1-8” rifling twists used in ARs (the original M-16 had a 1-14” twist rate), can stabilize bullets up to 80 grains. Generally speaking, bullets over 70 grains are match bullets designed for long range competitive shooting, whereas game bullets range from 60 to 70 grains. Every component bullet and ammo manufacturer now offer bullets in this weight range specifically designed for deer, antelope and feral hog hunting. By that I mean bullets — traditional, bonded core and monolithic — designed to hold together and penetrate deeply enough to get into the vitals. Recommended or not, guys are going to do it anyway, so why not give `em the best tools to do it with?
These new bullets are not going to end the argument as to whether or not the 5.56/.223 makes a good deer cartridge. Those who’ve had success with it are going to say it does. Me, I don’t think so, and I say that based on my own experiences and witnessing those of others. It can, however, be an adequate cartridge with a good bullet under some circumstances as dictated by range and angle. A shot at 200 yards from a bad angle? No.