18 Inch AR Barrel Questions

[Pappabear]

It appears every barrel has its own personality, but why gamble when you don’t have to. I like 556 chambers and I have enjoyed great accuracy with them. YMMV

If you buy a quality barrel and quality ammo, it SHOULD shoot.

PB

[Don Quijote]

That's how I was sold it too. However my results (WOA barrel) and reports from my last instructor were that the chamber was problematic with hot 55 gr (WCC), for example, ammo. Popped primers weren't uncommon. I definitely see spooky bulges near the rear of my brass if I shoot 5.56.

IMO, a good 5.56 chamber is a better choice.

Your example of one is absolutely no indication of the Wylde chamber's suitability for safely shooting 5.56 NATO ammo. It's just an indication of your barrel and its problems.

Too many people have had success running heavy loads (like 25 grains of RL15 topped with a Hornady 75 seated to 2.25) safely in Wylde chambered barrels. That includes me.

[Jammer Six]

Here's what I don't understand.

A .223 Wylde and 5.56 are different calibers. (As 5.56 and .223 are different calibers, for that matter.)

Why would you run a different caliber in any weapon? What is gained? Why not run the caliber the weapon is chambered for?

[Cokeman]

I use to think an 18" barrel was cool. In fact, I have two 18" rifles. But, I quickly realized that a good 16" will do anything you need within reason. The question that needs to be answered is what are you plans for this? Strictly a bench type rifle or something you plan on lugging around or using for HD/SD?

I’m not wanting it for home defense. I think my LMT fills that role. I’m thinking more along the lines of a 3 gun or bench rifle. I want to mount a scope on it, not a red dot or just iron sites. I’m also wanting less recoil which is why I am thinking I want a rifle length gas tube.

[Clint]

A 16" or 14.5" barrel can also work nicely for this.

The key to a smooth cycling barrel is a properly matched gas system length for that barrel length with a properly sized the gas port.

This means MID length for the 14.5" and longer than mid length (Extended/Intermediate) for the 16".

[Don Quijote]

Here's what I don't understand.

A .223 Wylde and 5.56 are different calibers. (As 5.56 and .223 are different calibers, for that matter.)

Why would you run a different caliber in any weapon? What is gained? Why not run the caliber the weapon is chambered for?

They are not different calibers. For that matter neither are 223 Remington and 5.56 NATO.

The CIP MAP limit for 223 Remington is identical to that of 5.56 NATO, SAAMI has a lower MAP for 223 Remington compared to CIP.

This isn't as simple as you think.

[Jammer Six]

They are not different calibers. For that matter neither are 223 Remington and 5.56 NATO.

The CIP MAP limit for 223 Remington is identical to that of 5.56 NATO, SAAMI has a lower MAP for 223 Remington compared to CIP.

This isn't as simple as you think.

I don't need it to be simple, but I would like to try to understand it. Are you saying that .223, .223 Wylde and 5.56 are merely different names for the same caliber?

[Renegade04]

I don't need it to be simple, but I would like to try to understand it. Are you saying that .223, .223 Wylde and 5.56 are merely different names for the same caliber?

Here is a good article to read that explains things fairly well.

https://www.americanweaponscomponent...e-vs-5-56-nato

[Don Quijote]

I don't need it to be simple, but I would like to try to understand it. Are you saying that .223, .223 Wylde and 5.56 are merely different names for the same caliber?

Forgive me if you know some of this already. All of what I say below needs to be known and understood to provide a thorough explanation

1. 223 Wylde is not a cartridge, it's the name of a chamber (and its reamer) designed by Bill Wylde. This Wikipedia article is a very accurate description of what it is, what it does, and why it came to be: https://en.wikipedia.org/wiki/.223_Wylde_chamber


2. 223 Remington and 5.56x45 are dimensionally the same exact cartridge. The former is the SAAMI (Sporting Arms and Ammunition Manufacturers Institute) and CIP (Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives) designation, the latter is the NATO designation.

3. 5.56 NATO is a shorthand name used to describe that the 5.56X45 cartridge has been adopted and standardized as a service cartridge by NATO and its member nations.


4. SAAMI (in conjunction with the American National Standards Institute, ANSI) develops and publishes standards for the testing of small arms and ammunition in the US. Those standards are voluntary, insofar as there is no law or regulation requiring that ammo or arms meet them before being offered for sale in the US. SAAMI centerfire rifle ammo standards are here: https://saami.org/wp-content/uploads...-SAAMI_CFR.pdf


5. CIP does the same thing as SAAMI with a few key differences. Number one, most countries outside of the US require by law proof testing of small arms and ammo before they are legal to sell. Number two, most of those countries have membership in the CIP or require the use of CIP standards. Number three, many countries require the proof testing be done by independent (and sometimes government owned) proof houses. In other words, manufacturer's proof is not enough. CIP rimless rifle cartridge standards are here: http://www.cip-bobp.org/homologation...idge_type_id=1


6. SAAMI and CIP pressure standards for small arms ammunition are not always the same for the same cartridge. That is the case for the 223 Remington (regardless of what you call it here or in Europe). The SAAMI maximum average chamber pressure (MAP) for 223 Remington is 55,000 psi. The CIP MAP for both 223 Remington and 5.56x45 is 4300 bar (62,366 psi). Any European-made 223 Remington ammunition sold here could potentially develop that pressure. Any European-made rifle marked "223 Remington" will have been proof tested based on the 62,000 psi MAP.

7. SAAMI chamber dimensions for 223 Remington rifles: https://saami.org/wp-content/uploads...FR.pdf#page=13 page 68. SAAMI velocity and pressure test barrel chamber dimensions for 223 Remington: https://saami.org/wp-content/uploads...FR.pdf#page=13 page 264

8. CIP chamber dimensions for 223 Remington rifles: http://www.cip-bobp.org/homologation...-170406-en.pdf. CIP velocity and pressure test barrel chamber dimensions for 223 Remington: http://www.cip-bobp.org/homologation...iii-en-cr1.pdf (basically take the chamber drawing and apply the tolerances specified in the annex).


9. US military ammo standards, see chapter 10 page for 5.56 ammo: http://pdf.textfiles.com/manuals/MIL...april_1994.pdf. In summary, max chamber pressure for M193 is 52,000 PSI, for M855 it is 55,000 psi, and for M995 it is 50,250 psi. Presumably those pressures were established in a 5.56 NATO chambered V&P test barrel but I haven't found a drawing for it. I would assume it's similar to the CIP test barrel. As an aside, the M197 high pressure (proof) test cartridge develops 70,000 psi which is not quite as high as the CIP proof pressure limit for 223 Remington of 5375 bar (77,958 psi).

10. As this post https://www.m4carbine.net/showthread...er-Differences points out, there are differences in where chamber pressure is measured between SAAMI and the military. ETA: this seems to support testing equivalency between NATO and CIP: https://en.wikipedia.org/wiki/NATO_EPVAT_testing

PS, your sig line is puzzling.

[markm]

Your example of one is absolutely no indication of the Wylde chamber's suitability for safely shooting 5.56 NATO ammo. It's just an indication of your barrel and its problems.

Too many people have had success running heavy loads (like 25 grains of RL15 topped with a Hornady 75 seated to 2.25) safely in Wylde chambered barrels. That includes me.

Your example of 1 is worthless. Why are you still posting on this site? You're an abrasive imbecile. I cited the reports from an instructor with the Sheriff's Office as to the unsuitability of (at least some) Wylde Chambers with 5.56 ammo... which mirrored my experience as well.