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AR-15 for Self-Defence
Lanark Sixgunner
Member Posts: 130 ✭✭
I am thinking of getting an AR for self-defence. I am somewhat confused, however, about chambers. Most of these rifles seem to be chambered in 5.56 NATO, and some in .223. I would like the 5.56 if only to take advantage of govt. surplus. But most good self-defence ammo is available only in .223. Can you shoot .223 ammo in a 5.56 chamber? Should you use govt. surplus for self-defence? What are the best company's? What capacity mags are the best?
Best
Best
Comments
most govt surplus differs in that the primer pocket is swaged to keep it waterproof. thats about it.
stay away from bullets that have some clear coating crap on them to keep them from corroding. it slimes up the gun.
Former Member U.S. Navy Shooting Team
Former NSSA All American
Navy Distinguished Pistol Shot
MO, CT, VA.
Best
However, the AR is not really a good choice for self or home defense unless you live in Iraq or D.C. Too much over penetration and unneccessary risks to unintended parties (neighbors, kids, etc.)
In the 1950's, the US military adopted the metric system of measurement and uses metric measurements to describe ammo. However, the US commercial ammo market typically used the English "caliber" measurements when describing ammo. "Caliber" is a shorthand way of saying "hundredths (or thousandths) of an inch." For example, a fifty caliber projectile is approximately fifty one-hundredths (.50) of an inch and a 357 caliber projectile is approximately three-hundred and fifty-seven thousandths (.357) of an inch. Dimensionally, 5.56 and .223 ammo are identical, though military 5.56 ammo is typically loaded to higher pressures and velocities than commercial ammo and may, in guns with extremely tight "match" .223 chambers, be unsafe to fire.
The chambers for .223 and 5.56 weapons are not the same either. Though the AR15 design provides an extremely strong action, high pressure signs on the brass and primers, extraction failures and cycling problems may be seen when firing hot 5.56 ammo in .223-chambered rifles. Military M16s and AR15s from Colt, Bushmaster, FN, DPMS, and some others, have the M16-spec chamber and should have no trouble firing hot 5.56 ammunition.
Military M16s have slightly more headspace and have a longer throat area, compared to the SAAMI .223 chamber spec, which was originally designed for bolt-action rifles. Commercial SAAMI-specification .223 chambers have a much shorter throat or leade and less freebore than the military chamber. Shooting 5.56 Mil-Spec ammo in a SAAMI-specification chamber can increase pressure dramatically, up to an additional 15,000 psi or more.
The military chamber is often referred to as a "5.56 NATO" chamber, as that is what is usually stamped on military barrels. Some commercial AR manufacturers use the tighter ".223" (i.e., SAAMI-spec and often labeled ".223" or ".223 Remington") chamber, which provides for increased accuracy but, in self-loading rifles, less cycling reliability, especially with hot-loaded military ammo. A few AR manufacturers use an in-between chamber spec, such as the Wylde chamber. Many mis-mark their barrels too, which further complicates things. You can generally tell what sort of chamber you are dealing with by the markings, if any, on the barrel, but always check with the manufacturer to be sure.
Typical Colt Mil-Spec-type markings: C MP 5.56 NATO 1/7
Typical Bushmaster markings: B MP 5.56 NATO 1/9 HBAR
DPMS marks their barrels ".223", though they actually have 5.56 chambers.
Olympic Arms marks their barrels with "556", with some additionally marked "SS" or "SUM." This marking is used on all barrels, even older barrels that used .223 chambers and current target models that also use .223 chambers. Non-target barrels made since 2001 should have 5.56 chambers.
Armalite typically doesn't mark their barrels. A2 and A4 models had .223 chambers until mid-2001, and have used 5.56 chambers since. The (t) models use .223 match chambers.
Rock River Arms uses the Wylde chamber specs on most rifles, and does not mark their barrels.
Most other AR manufacturers' barrels are unmarked, and chamber dimensions are unknown.
Here's what Winchester has to say...
http://www.winchester.com/lawenforcement/news/newsview.aspx?storyid=11
.223 Rem VS 5.56mm
There are a lot of questions about these two cartridges. Many people think they are identical - merely different designations for commercial and military. The truth is that, although somewhat similar, they are not the same and you should know the differences before buying either cartridge.
The cartridge casings for both calibers have basically the same length and exterior dimensions.
The 5.56 round, loaded to Military Specification, typically has higher velocity and chamber pressure than the .223 Rem.
The 5.56 cartridge case may have thicker walls, and a thicker head, for extra strength. This better contains the higher chamber pressure. However, a thicker case reduces powder capacity, which is of concern to the reloader.
The 5.56mm and .223 Rem chambers are nearly identical. The difference is in the "Leade". Leade is defined as the portion of the barrel directly in front of the chamber where the rifling has been conically removed to allow room for the seated bullet. It is also more commonly known as the throat. Leade in a .223 Rem chamber is usually .085". In a 5.56mm chamber the leade is typically .162", or almost twice as much as in the 223 Rem chamber.
You can fire .223 Rem cartridges in 5.56mm chambers with this longer leade, but you will generally have a slight loss in accuracy and velocity over firing the .223 round in the chamber with the shorter leade it was designed for.
Problems may occur when firing the higher-pressure 5.56mm cartridge in a .223 chamber with its much shorter leade. It is generally known that shortening the leade can dramatically increase chamber pressure. In some cases, this higher pressure could result in primer pocket gas leaks, blown cartridge case heads and gun functioning issues.
The 5.56mm military cartridge fired in a .223 Rem chamber is considered by SAAMI (Small Arm and Ammunition Manufacturers Institute) to be an unsafe ammunition combination.
Before buying either of these two types of ammunition, always check your gun to find what caliber it is chambered for, then buy the appropriate ammunition. Most 5.56mm rounds made have full metal jacket bullets. Performance bullets - soft points, hollow points, Ballistic Silvertips, etc. - are loaded in .223 Rem cartridges. Firing a .223 Rem cartridge in a 5.56mm-chambered gun is safe and merely gives you slightly reduced velocity and accuracy. However we do not recommend, nor does SAAMI recommend, firing a 5.56mm cartridge in a gun chambered for the .223 Rem as the shorter leade can cause pressure-related problems.
Winchester Law Enforcement Ammunition East Alton Illinois
It's widely used by LE tactical unit entry teams due to lower penetration of walls than most defensive handgun caliber JHP loads.