Planter

I had a scope rail put on the Ruger Mini-14 which completely replaces the heat disapator and let me get away from the side saddle mount. Sweet set-up with the holo-sight for what is essentially a short range light barreled gun.

The problem was that the gun started cycling VERY poorly. First round chambered and sometimes the 2nd round but I couldn't get thru a 5 round factory clip never mind a 20!!

The guys at the gun store said I had to use .223 and NOT 5.56 ammo. I was under the impression it was the same thing but they say a 5.56 in a longer round. ( not Caliber ). They cleaned and lubed it and said it worked great. ( It WAS clean )

Does anyone know if thats fact or fiction?? Gonna hit the range this after and it had better burn thru a 20 round clip with NO problems!!!

I want to make sure it works before I bury it for when they come for all our guns.

boilermaker85

5.56 is the nato designation for .223 its the same or at least i know no diff. i own several ar's and have shot truck loads of nato and .223 ive never had a single issue. ALTHOUGH AS ANY AUTO LOADER they can be picky eaters! were you using reloads? swollen cases? or cheap ammo brown bear wolf etc? metal case not brass id try some remington or federal {federal green tips are my fav.] hope these ideas help?

psdavidson

The 5.56 round was designed after the common sporting round, but has two slight, although important, differences. Both are minor, but enough to cause some major if not deadly problems if you put 5.56 into a .223 chamber. .223 may be fired in a 5.56 chamber however. Here are the reasons why:

1) The 5.56 round has a length .002 longer than the .223 round.
2) The 5.56 round has a slightly steeper shoulder angle.
3) The military 5.56 brass depending on make is thicker and exceeds pressure
NATO specification 5.56mm ammunition is loaded to a pressure that exceeds standards set out by SAAMI guidelines for it's civilian twin, the .223 Remington. While use of either commercial or NATO specification ammuniton is safe to use in the AR15/M16 series rifles, the use of NATO specification ammunition in other firearms may result in excessive chamber pressure.

Planter

I never had a problem using cheap ammo prior to having the rail put on but I made sure I shot some high quality stuff thru it prior to taking it back to the smith. The wolf and the like are pretty poor stuff but the kids can burn thru a lot of ammo so it was fine for plinking.$$$$$ For some reason I like my ammo to be made of brass.....

I even ejected rounds that had chambered and could find no sign on the bullet that it was binding. I'm guessing that the new rail is too tight on the gun and causing the problem. I may end up spacing it off a little more with some small stainless washers.

I always thought .223 was 5.56 so I just don't know. The gun was never picky about what it digested but it always liked factory clips...

psdavidson

most all ar's is stamped either .223/5.56 or with 5.56 which the .223 will shoot in both. the biggest problems with 5.56 is in bolt actions where there is a tighter tolerance

Saxman1819

5.56 has higher pressures when fired than the .223. If the barrel says .223 then DO NOT shoot 5.56 in it. If it says 5.56, you can shoot .223 or 5.56.

psdavidson

did you field strip the 14 and check the bolt to see if the rail screws is rubbing on the bolt? I assume the rail holes is tapped above the bolt? was this wolf ammo? lacquered finish or zinc coated?

boilermaker85

Thanx for the info i didnt know those things

driftrider

Numbers 1 and 2 are not correct. 5.56mm NATO and .223 Remington are identical in external dimensions. If you measured both cases you would not be able to tell the difference without a headstamp.

#3 is partially correct. Mil-Spec brass can be heavier (i.e. have thicker case walls) than some .223 ammo, though some ammo manufacturers load SAAMI 223 Rem loads in mil-spec brass. This is because Mil-Spec 5.56mm ammo is loaded to 60,000 cup vs. the SAAMI .223 Rem max operating pressure of 50,000 cup. It's also because the 5.56 ammo has to be able to take one heck of a beating without being deformed in order to reliably function through automatic weapons under combat conditions. Machineguns and machinegunners beat the snot out of their ammo, and the thicker cases also help reduce cook-offs as well.

Now, aside from the added pressure that 5.56 NATO ammo is loaded to, there is also a difference in the CHAMBER of a 5.56mm rifle versus a .223 Remington chamber. The 5.56 NATO chamber has a much longer and generously cut freebore and a shallower angle as the bullet engages the rifling. This mitigates the higher pressures generated by the 5.56 loads at the potential cost of some accuracy. The SAAMI compliant .223 Rem chamber uses a much shorter throat with a steeper angle between the freebore and rifling. This improves accuracy, but also significantly increases peak chamber pressure. SAAMI spec 223 Rem ammo is loaded to lower pressures to accommodate the shorter freebore without creating a dangerous condition. But when you shoot mil-spec 5.56 NATO ball ammo in a .223 chamber, not only is the round loaded to 10,000 cup more pressure, but combine that with the much shorter freebore and pressure can further spike as much as 20,000 cup higher, or 80,000 cup, which is EXTREMELY high and potentially very dangerous. The good news is that most modern rifles are tough enough to handle such pressure, at least for awhile, without failure. But if a case ruptured, or metal fatigue sets in from repeated overpressure, you could wind up with a face full of shrapnel with no clear sign of impending failure.

The moral of the story is that you should NEVER fire and cartridge stamped 5.56 NATO in a barrel stamped .223 Rem, unless you've contacted the manufacturer to make sure the throat is cut to 5.56 specs. I understand that the Mini-14 is an example of such a case, where Ruger stamped the barrels .223 Rem but it's got a mil-spec chamber because they figured that some people would ignore the barrel stamp and fire 5.56 ammo through them. Some AR's also are (incorrectly) stamped .223 Rem when they are 5.56 chambers. Only the manufacturer or a gunsmith with a chamber mould can confirm the actual chamber specs. When is doubt, don't shoot 5.56 ammo in a .223 Rem chamber.

All that said, the reverse is not true. If you have a confirmed 5.56 NATO chamber, it is perfectly safe to shoot .223 Remington ammo in it. The only negative consequence may be slightly reduced accuracy and velocity, but it is completely safe.

Many AR manufacturers are now chambering their rifles in 5.56 NATO Match, or .223 Wylde. These chambers are both compromises between the 5.56 NATO and .223 Rem chamber, in order to allow the safe use of mil-spec ammo, while not sacrificing as much accuracy.

Mike

psdavidson

thanks for the correction. I can't be right all the time...at least that's what the wife says LOL