I don't think I've ever seen a set of 5.56 NATO reloading dies.
AR15 .223 Rem or 5.56 Nato
- Thread starter Papa Charlie
- Start date
jelenko
Gold $$ Contributor
Right. But are the cartridge specs all the same, just the chamber dimensions are different?
jelenko
Gold $$ Contributor
I am not an expert on this. But, from this chart http://www.ar15barrels.com/data/223-556.pdf .190 freebore is not a 556 NATO. From that chart, .190 freebore would seem to be an unusual one. I may have read people using 90 gr bullets use an extra long freebore.
XTR
F-TR obssessed shooting junkie
The question is rhetorical. That reamer is not particularly unusual, the standard PT&G ISSF 223 reamer has a .169 freebore. They are designed for shooting 90 gr bullets, but the question again is "What is it?"
I might argue that only chambers cut to the 5.56 NATO standard are in fact 5.56 NATO, and those cut to the SAAMI 223 Remington specs are 223 Remington and all other are a wildcat of some variant or another.
This whole thing comes back to the tempest in a teapot that if you jam bullets into the lands you can (will) increase pressures, but this is the only conversation that I know of where that discussion digresses to the idea that it's patently unsafe to chamber your [insert load] because it's jammed. I have never seen any documentation that any component of a rifle marked 223Rem is pressure tested to any lower pressure than one marked 556NATO. They all get bolts, BCGs, barrels and extensions from the same places from the same materials.
The one possible real danger is that in an AR15 platform a jammed bullet may result in a configuration where the weapon is able to be fired w/o being fully in battery which could result in a KABOOM.
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SAMMI .223 = CIP 5.56 mm (metric) = "same" max pressure
5.56NATO = CIP + (more) STANAG 4172 = but the "same" max pressure
5.56 NATO chamber in theory is larger than .223 or Wylde, is possible to have overpressure in minimum .223 chamber.
5.56 NATO has to fit automatic weapons in field condition = ammo min, chamber max - no overpressure.
In Europe, the US has two forces, one is in NATO (STANAG 4172), one is an occupational force with different laws and regulations.
5.56NATO = CIP + (more) STANAG 4172 = but the "same" max pressure
5.56 NATO chamber in theory is larger than .223 or Wylde, is possible to have overpressure in minimum .223 chamber.
5.56 NATO has to fit automatic weapons in field condition = ammo min, chamber max - no overpressure.
In Europe, the US has two forces, one is in NATO (STANAG 4172), one is an occupational force with different laws and regulations.
XTR
F-TR obssessed shooting junkie
This is just not the case, if it were so then every minimum spec 308 "Match" chamber out there would be running "higher" pressures because they are cut smaller. Go back and look at those drawings, there is 3.7 thousandths difference in the smallest and largest base, and the shoulders are smaller on the NATO cases. There is more variation in brass thickness between manufacturers.
If the brass fits in the chamber then the only place a chamber is going to make a significant difference in pressure is if the neck is too tight for the brass, and that will give you a lot of pressure, or if the freebore is short and you are jamming rounds. There are a number of estimates out there for what jamming does, Quick Load will even do it. The other would be if you jam hard enough to push the bullet deeper into the case you're getting into a different situation.
3Sigma
Silver $$ Contributor
I know this is purely academic at this point, but what about projectile type? All else being equal, would jamming a steel core (M855) cause a higher pressure spike than a FMJ (M193)?
FWIW, those who have traveled this road already found chambers that provide better accuracy than 5.56 and allow compatibility. Just follow their lead.
Full disclosure, I have a 5.56 chamber and shoot in ot 223 often. I meets my accuracy expectations for a cheap off the shelf AR, 1.5 moa or better with 5 shots. I've shot better ARs, but with Wylde chambers and much better BCG and barrels.
FWIW, those who have traveled this road already found chambers that provide better accuracy than 5.56 and allow compatibility. Just follow their lead.
Full disclosure, I have a 5.56 chamber and shoot in ot 223 often. I meets my accuracy expectations for a cheap off the shelf AR, 1.5 moa or better with 5 shots. I've shot better ARs, but with Wylde chambers and much better BCG and barrels.
ronemus
Gold $$ Contributor
To answer "what is it?" we can only say it's neither .223 or 5.56 - it's one of many wildcat variants out there. I shoot a custom match chamber (.223 Ronemus) that is tweaked to suit my personal bias; John Holliger has the reamer at White Oak Precision, and anybody who wants one chambered that way can get it from him. It requires turned necks and brass must be religiously trimmed to length; it has a long freebore to take advantage of DPMS "VLD magazines" thus maximizing the available powder volume. It allows me to use max loads with VV N-550 and molyed Hornady 75 gr bullets - BTHP from the magazine and A-Max single loaded. That's what I run for NRA Highpower & Long Range, and as far as I know no one else runs that recipe. To each his own! There are many custom chamberings and loads being used, and each is optimum for different uses.
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XTR
F-TR obssessed shooting junkie
If I pick up a brass case from the range that is marked 556 NATO and reload it with a 62gr FMJ loaded with 24 gr of Varget and an OAL of 2.250 what is it?
If I do the same with a case marked 223Rem is it something different?
If I do the same with a case marked 223Rem is it something different?
The NRA and ICFRA consider it to be a 223 and suitable for competition in F-TR.
For your reading enjoyment:
https://en.wikipedia.org/wiki/5.56×...m NATO chamber,the rifling engages the bullet.
https://en.wikipedia.org/wiki/5.56×...m NATO chamber,the rifling engages the bullet.
I doubt it's more popular than 5.56 NATO.
Wylde is, overall, though the best choice for a 223-ish AR chamber.
That's because the Nato is the CHAMBER and the dies are for the cartridge.
Now you have seen a die set marked 5.56, the European CIP considers the .223 and the 5.56 to be one and the same cartridge.
The main difference between these chamberings is the throat length. "BUT" the throat in my Savage .223 with a 1in9 twist is longer than my AR15 rifles. So even the .223 throats vary in length and diameter. If you check the rifles with a 1in12 and 1in 14 are the rifles with the shorter throats.
Below look at throat variations for the .223 and 5.56, throat diameter "G", free bore length "N" and throat angle "R".
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