Accuracy of .223 in a 5.56 barrel?

[rcmodel]

The ONLY certified guaranteed 100% legitimate over-pressure instances I have ever heard of since the 5.56 NATO cartridge became widely enough issued to the military to be stolen and shot in .223 rifles?

Happened with custom shop Remington Model 40-X benchrest rifles, and SAKO Vixen hunting rifles in the late 1960's.

Military 5.56 NATO ammo fired in them produced loose primer pockets, and in some cases, blown primers.
With no damage to the rifles, or shooters.

But keep in mind the 40-X's were Mike Walker run, Rem Custom Shop Bench-rest or Varmint rifles with very tight bores, minimum spec chambers, and very tight throats in keeping with a custom made bench rest rifle that would meet Mike Walkers very strict accuracy standards.

There were also some 60's era SAKO Vixen .223 Rem rifles imported with .223" (instead of .224") bores that blew primers till who laid the chunk with military 5.56 ammo.

That, IMO, is where & how the whole SAAMI .223/5.56 warning came to be!

Manufactures don't want to be sued due to a firearm failure.
So they aren't in the business of making .223 rifles that blow up if every customer who doesn't know the difference, or reads the warnings in the owners manual shoots 5.56 NATO in them.


So, if you don't have a 1960's era Remington 40-X benchrest rifle, or 1960's era SAKO Vixen hunting rifle?

Fogadaboutit!
Ain't no big thang with any current production rifle.

rc

 

[MistWolf]

Nevermind

 

[moxie]

The 5.56mm M193 cartridge was never actually adopted by NATO, even though much of it has the NATO circle and cross on the headstamp. Nevertheless, it was used by many NATO countries, including the U.S., until the M855/SS109 came along in the early '80s. It was adopted by NATO.

The faster 1:7 twist was implemented in the M16A2, and subsequent weapons based on the AR platform, to accomodate the heavier 62 gr. bullet of the M855 round. It had nothing to do with tracer rounds. Most earlier M16 and M16A1 and various shorties had the 1:12 twist. A few had 1:14.

 

[ugaarguy]

The faster 1:7 twist was implemented in the M16A2, and subsequent weapons based on the AR platform, to accomodate the heavier 62 gr. bullet of the M855 round. It had nothing to do with tracer rounds.

As I understand it, stabilizing the M855's accompanying M856 Tracer with its even longer projectile had quite a bit to do with the selection of the 1:7 twist.

 

[moxie]

Although a tiny bit longer, and a tad heavier, I don't recall the tracer being a driver in the drama. But I might have been looking at it from a different point of view, being Air Force. I'd like to hear from some guys who've been deployed recently as to extent of use of tracers. As far as I know, use of tracers in M16/M4 weapons has been minimal, with the M249/SAW using them more. Those of course were designed with the M855/M856 in mind and had 1:7 barrels from the get go.

 

[rskent]

Will I see a loss of accuracy if I'm shooting .223 in a 5.56 barrel?*

For me, probably not. At least not that I could tell on target with the barrel you are looking at.

I do plan to begin loading for it at some point in the near future.

If you want to get any real accuracy out of your rifle you will need to. It is possible to find to
one magic factory load that shoots in your gun. It is a lot easier and cheaper to just build them.
Once you get the hang of it, it is very easy to dial in a load to your gun.