5.56 NATO vs .223 Remington

[Excalibur]

I've been recently hearing a lot of confusions that I want to be clear on. When I was at a gun store with a friend and holding an AR15, I said it's chambered in .223. My Marine buddy then say that it's also called 556, but correct me if I'm wrong. Is there a real difference between what the military uses and that NATO calls 5.56mm to that of the .223 which is by US measurements even though in the US military they still call it a 5.56mm instead of .223.

My question is what is the difference in when we have civilians with AR-15s chambered in .223 vs a military M16 chambered in 5.56mm

[Yournamehere]

The .223 Remington was the cartridge from which the 5.56mm NATO was developed. The 5.56mm NATO is loaded to higher pressures, as all NATO rounds are, and are said to not be safe fired from guns specifically designated for the .223 Remington cartridge. You can fire .223 Remington rounds out of a gun designated for 5.56, as it is the higher pressured cartridge and therefore the gun built for it has higher tolerances. They are the same, but then again, they arent.

This can also be said for the .308 Winchester and the 7.62mm NATO round.

[Gunmaster45]

That's us civies getting the shit end of the stick, as usual. :rolleyes:

[Yournamehere]

I'm pretty sure you can buy an AR-15 chambered in 5.56mm NATO, but good luck finding the ammo.

[Gunmaster45]

Won't any AR-15 with a steel reciever (not alloy crap they usually make them with) withstand higher pressure? My Bushmaster has a steel reciever, so I'm wondering.

[Yournamehere]

Actually the original models were all manufactured with high strength Aluminum recievers, and they took the 5.56mm NATO rounds, but as we've learned before, the reciever can be made of pretty much anything, (like plastic or wood). The upper should be fully constructed of steel, and almost always is. A steel reciever would probably make the gun a bit tougher, but add some weight as well.

[Gunmaster45]

Yeah, my Bushmaster is a carbine and is just as heavy as a full length Colt HBAR, because the Bushmaster is better made of more solid metal.

[Nyles]

Actually, the difference is in the leade (the space between the end of the cartridge and where the rifling starts. It's somewhat longer in the 5.56mm NATO, which can lead to reduced accuracy when firing some .223 cartridges out of a NATO chamber, or reliability when firing NATO ammo out of a match-grade .223 chamber.

NATO allows a different max pressure than SAAMI, but that's got more to do with different methods of measuring than anything - the European proof houses give the same max pressure for both. Military cartridges have thicker brass since they're more concerned with reliability than reloadability. SS109 or Mk.262 could potentially lead to higher pressure in a .223-spec chamber, but not so much that it's gonna blow up in your face.

[Phoenixent]

Thanks Nyles for explaining the difference between .223 Rem and 5.56 NATO.

We had a PD bring in their Bushmaster built carbines with stainless steel barrels as they would not function on Full Auto firing 5.56 NATO. We had to go in with a 5.56 NATO chamber reamer and give them the correct chamber for the cartridge. Once that was done they worked perfect in Full Auto mode.

[Phoenixent]

Won't any AR-15 with a steel reciever (not alloy crap they usually make them with) withstand higher pressure? My Bushmaster has a steel reciever, so I'm wondering.

Did you check that receiver with a magnet at the rear were the lug for the take down pins? I wondering as the only steel receiver I have seen is on a .308 model AR and it was fully machined.

The receivers used by Colt, FN, LMT, S&W, DPMS, Armalite, Bushmaster and others are 7075 forgings which is the exact same material used in jet aircraft including the latest fighters like the F-22 and F-35.

[Phoenixent]

The upper should be fully constructed of steel, and almost always is. A steel reciever would probably make the gun a bit tougher, but add some weight as well.

Link please to a government used steel receiver on a M16 or AR-15 civilian model.

If no link company name would do.

[Yournamehere]

Eh, GM just said his Bushmaster is built on a steel receiver. It doesn't really matter what it's made of, though, as I've said.

[Gunmaster45]

Maybe I'm wrong, but the thing feels too damn heavy to be aluminum to me.

[Yournamehere]

Actually on the Bushmaster Website, it says that their receivers are either aluminum or carbon fiber, no steel, so you probably have an aluminum one, and yes, they are a bit heavy even with this. Aluminum isn't a helluva lot lighter than steel, depending on what's being forged.

[Gunmaster45]

Huh, I learned something. :)

[Phoenixent]

To bad I was hoping to build some steel M16's so the actors have a harder time destroying them and listen to them bitch about the weight. They bitch about the weight of the M4 nothing but whiners.

[k9870]

I'm pretty sure you can buy an AR-15 chambered in 5.56mm NATO, but good luck finding the ammo.

Um, may compays make 556 chambers, actually, most do. very few are 223 only. NATO-spec FMJ is common, and geerally cheaper.

[Yournamehere]

The only ones that interest me are the old Colt Sporters which are stamped .223, so the're out there. I haven't seen 5.56 NATO in a shop, but I see .223 everywhere, so maybe it's the area, too.

[k9870]

A lot say ".223 caliber" biut if you read manuals it will say both are safe.

[Gunmaster45]

Speaking of AR-15s, my dad now has two Colt A2 HBARs, and one A1 SP1 in his shop. One HBAR is pre-ban so it can keep its bayonet lug and A2-flashhider, while the other is post ban, so my dad sadly had to grind off the bayonet lug and replace the flash hider with a Miculek muzzle break. It's still a nice looking gun, but it's been '96 neutered. Clinton/Biden, you cocksuckers.

The SP1 was pretty nice, I didn't check the caliber markings though.

This is the most "assault rifles" my dad's ever had out in the shop. And now he's bought the Bushmaster and the Jager AP-80, so I'm pretty happy. I'm cradling the Jager as I speak. :D Hell, I'll take a picture...

[Yournamehere]

Take a picture of the A1 SP1. Then sell it to me. For not a lot of money. Please?

[Gunmaster45]

I''ll talk to my dad. I can't take a picture of the SP1 right now, the shop is locked. My dad was kind enought to late me take out the Jager though, so that's why I have it handy.

And I figure the SP1 would go for $700-$800. It's in great shape and has an early serial number. We can't track it down in year quite yet, but we figure it was made in the early '70s.

[Gunmaster45]

Grr, damn camera won't work on computer for some reason. Jager pics'll have to wait. :o

[Yournamehere]

800 dollars is a godsend for an SP1! It hasn't been New Yorkerized has it? Did you remove the evil barrel shrouds or the stocks with the thing that goes up?

[Gunmaster45]

It's all original. My dad'll likely sell it on Gunbroker, so if he puts it up I'll send you the link.

He sells them through a guy he's friends with, username is Tipup1.

[Excalibur]

I'll buy that SP1 for 800. It's a steal

[Gunmaster45]

On Gunbroker it could go for much more, so don't get your hopes TOO high. ;)

[Gunmaster45]

Bad news. My dad had accidentally priced it under the wrong gun in his book so the running price was actually. $1,400 off the rack. So my bad.

You won't have to worry about it though because someone bought it today. I got to shoot it before it left though, it put out a good 1" group. The chamber was lubed too much though (causing extra friction in cycling and more recoil) so the charging handle latch got unhooked and the charging handle smacked me in the nose. My dad put old the old triangular forend on it and it was out the door. :(

I also shot the two HBAR A2s. One I realized has no magazine fencing on the lower, but it was clearly marked AR-15 A2 Sporter HBAR, so I wonder if magazine fencing isn't the best ID of an SP1 lower...

The one with the Miculek muzzle break was lots of fun to shoot, no kick and very accurate.

[Yournamehere]

Yeah a lot of the Civvy Colts don't have the fencing, or the notches where the selector switch stops. Still, they's good AR-15s. I've been thinking about getting an A2 that still has the A1 sight instead of having to search for a full A1 upper.

[Gunmaster45]

What is that, a Model 715 upper?

[Yournamehere]

Essentially yes, but it's standard on certain AR-15A2s. Bushmaster makes one too for building on.

Here's an example.

http://v4.beta.gunbroker.com/Auction/ViewItem.aspx?Item=135798245#PIC

[MT2008]

I also shot the two HBAR A2s. One I realized has no magazine fencing on the lower, but it was clearly marked AR-15 A2 Sporter HBAR, so I wonder if magazine fencing isn't the best ID of an SP1 lower...


I'm pretty sure all of the original AR-15 A2s (regular and HBAR) had the exact same lower receiver as the Sporter I and Sporter II. I don't think Colt started selling them with the fencing around the mag release until around 1990. At least, that's the impression I get from looking at my Dad's old Gun Digest issues.

[Gunmaster45]

I guess that makes sense then. I learned something...

[Satory]

I am considering the purchase of a Remington Model 750 semi-auto rifle. Anyone have any experience with this rifle? Doing some research on other forums, there was a lot of posters that had problems with feeding. Also how accurate are they?

[predator20]

I am considering the purchase of a Remington Model 750 semi-auto rifle. Anyone have any experience with this rifle? Doing some research on other forums, there was a lot of posters that had problems with feeding. Also how accurate are they?

My dad has a Model 750 chambered in .308, on rare occasions he'll have trouble feeding 7.62 surplus stuff. Accuracy is as good as any average rifle.