A while back, I highlighted the differences between .223 Rem. and 5.56 NATO cartridges. While the external dimensions of the cartridges are the same, the chambers for the two designations are completely different. The 5.56 NATO employs a slightly larger chamber dimension, as well as a longer leade—the distance from the bullet’s resting place in the chamber to that point at which it engages the rifling—and therefore 5.56 NATO ammunition is loaded to a higher pressure. Our sporting .223 Rem. on the other hand, is loaded to a much-lower pressure, and has a much-shorter leade dimension. The general rule: It is safe to fire .223 Rem. ammo in a 5.56 NATO chamber, but the reverse is not true. One Mr. Bill Wylde, of Illinois, solved the issue with a bit of engineering genius. He created a hybrid chamber, called the .223 Wylde.
As with most thing genius, his design is simple, yet extremely effective. Wylde took the leade angle of the 5.56 NATO design and mated it to the tighter chamber body dimension and leade length of the .223 Rem. design. Wylde’s chamber gives enough room in the throat so 5.56 NATO cartridges won’t build dangerous pressure, but keeps the improved concentricity—and resulting accuracy—of the .223 Rem. The .223 Wylde chamber allows the owner to shoot both types of (identically dimensioned) ammunition without a worry in the world.
I first met the .223 Wylde chamber in a buddy’s AR-15; it was a nondescript-looking Rock River Arms gun, but man, this rifle shot. I’d put it up against any of my small-bore bolt action rifles, including my prized .22-250 Rem.; this rifle was that accurate. And, to further dizzy my brain, it really didn’t matter what you fed it; nearly everything shot well, but it would take Black Hills remanufactured and print tiny, little groups that would make any shooter cock an eyebrow.
Now this is not to say that gas guns aren’t usually accurate, but this gun is exceptional. My pal explained he opted for the .223 Wylde chamber, and he remains extremely happy with his choice. The rifle digests .223 Rem. factory ammunition as well as it does the cheaper 5.56 NATO stuff, with no hiccups in feeding or extraction.
“I really can’t see why anyone would have anything else,” he exclaimed. “I can feed this gun just about anything.” I can’t argue.
Is the conversion to a .223 Wylde worthwhile? In my experiences, absolutely. Though there are many rifles chambered to .223 Rem. that are seriously, wonderfully accurate, I’ve noticed that almost all the .223 Wylde barrels I've seen are equally precise. And why wouldn’t they be? After all, the only real change is the angle of throat—changed just enough to avoid that dangerous pressure spike—and it gives you all the flexibility in the world.
For me, part of the idea of choosing a military cartridge in the first place is that you’d always be able to use surplus military ammunition in a pinch; however owning a .223 Rem. doesn’t always work out that way. Yes, I've had shooters swear up and down that they’ve been firing 5.56 NATO ammunition from their .223 Rem. chamber for years, with no adverse effects. I’ve also seen guns damaged by this very act, and I, for one, don’t like taking those kinds of chances.
Why not just shoot the 5.56 NATO chamber and be done with it all? Well, I find the tighter specifications of the Wylde chamber have shown an improvement in accuracy over the more generously sized 5.56 NATO chamber, and I’m all about accuracy. Each of you may have your own experiences. Admittedly, I've seen some ‘sloppy’ 5.56 NATO rifles shoot like a dream, but based upon those rifles I have shot, as well as the multitude of success stories regarding the .223 Wylde chamber, it simply makes the most sense.
For the AR-15 platform, changing to the .223 Wylde chamber is as easy as swapping barrels. For the bolt-rifle crowd, it will require a gunsmith and a reamer if you have a .223 Rem. chamber. If you have a bolt rifle in 5.56 NATO, you’ll have to rebarrel the rifle in order to get the .223 Wylde chamber.