This is a discussion on Choosing a Semiautomatic Centerfire Rifle- Where to Begin? within the Defensive Rifles & Shotgun Discussion forums, part of the Related Topics category; Originally Posted by BAC I don't think there is a better rifle caliber for home defense than the 5.56. The problem is you can't get ...
5.56mm is the same as .223 but is a little more powerful, if you have a gun chambered for 5.56 it will shoot .223 but not vice versa.
The majority of AR15s are going to be chambered in .223 Rem or have a Wylde chamber. Rifles chambered in .223 Remington are specced to meet SAAMI standards, which I think are 50,000 CUP. Rifles chambered for 5.56x45 NATO are specced to meet higher NATO standards, which are higher in pressure (60,000 CUP) and involve a longer throat than the .223 chambered rifles to accommodate the generally longer 5.56 NATO bullets. I don't know much about Wylde chambers, but I believe they are SAAMI specced but have longer, 5.56-like throats so they're a little better at accommodating the NATO caliber.
Bear in mind that the marking on the rifle does not guarantee the it will be chambered in that caliber. Several companies have been marking 5.56 on their firearms for years despite them being chambered in .223 Rem or having Wylde chambers. Most of the biggest manufacturers are guilty of this (Bushmaster, DPMS, Olympic Arms, Rock River Arms, Stag, and the various kit gun manufacturers). The best thing to do if you're concerned about not having a 5.56-chambered rifle is to send it to a qualified gunsmith with a 5.56 reamer and have them go over the rifle. If you don't expect to be shooting a lot of 5.56 ammunition, a .223 or Wylde chamber is likely to be sufficient. Just watch the pressures if you're reloading or using hotter ammo.
For the money, it's almost impossible to beat an AK. Or even one of their clones like Saiga. They're so reliable that words fail me...they chew up any kind of ammo in any conditions and they're a blast to shoot. If you're so concerned about long range accuracy then buy a nice deer rifle or build a sniper rifle in 308...optics are paramount for shooting distances any further than an AR or AK can handle. They're short barreled assault rifles made for close range fighting...not for distance shooting. Can you slap a huge scope on one and a bi-pod?? Sure...but why would you? You'd be far better served with a weapon that is designed for that intended purpose, and the intended purpose of an AR or an AK is combat...not tack driving.
"Any rationally thinking person is armed" ---Hinds Co. constable John Lewis