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  #1  
Old 03-31-2018, 07:01 AM
pocketshaver pocketshaver is offline
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Default .223 or is it 5.56

Since you small bore guys are more up with throats than other places are ill ask this one.

.223 Remington
.223 Remington service rifle load data
5.56x45

5.56x45 is supposed to use a small magnum primer to get the "full pressure" but manuals just say us standard small rifle primers

Brass thickness.
5.56 is always supposed to be thicker then .223 Remington, just like 7.62x51 is thicker then .308 Winchester. But with the fact so many companies are making brass now, there is almost no difference between the two.

Lake City and Federal Cartridge brass for 5.56 and .223 is the same thickness, capacity, etc.

So for sensible logic, the case thickness has become more of a "balloon head cases for 45 colt hold more powder then modern solid head cases" and a "starline 45 colt brass holds 10 grains of water, while Remington holds 10.56 graisn of water"

pressure wise the adage 5.56 is higher is purely on how its measured looking at nosler and hodgdon data

nosler
5.56x45 H4895 start 22.0 gr max 24.0 69 grain HPBT

Hodgdon
.223 Remington H4895 Sierra SP
start 24.0 max 26.0 compressed

Not a perfect comparison but same powder and payload, the "higher pressured" cartridge SHOULD need a higher starting charge right?

And if the .223 is daintier, how can it take that much of a higher powder charge that cant be compensated by seating depth or even a 1% difference is case capacity?

SAAMI drawings for the .223 chamber are still dated from the early 1980s before people started making .223 I anything other then 1:12 1:14 twist rates, as a result the throat/lead never had to change. But as .223 chambered guns come in 1: and 1:8 and 1:9 twists, how can those SAAMI drawings be considered the go to legitimate dimensions as the heavy bullets are NOT supposed to be able to work at all with the original .223 throat?
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  #2  
Old 03-31-2018, 02:24 PM
Bill K Bill K is offline
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Default .223 or is it 5.56

They are basically the same, except when the 5.56 case is formed and the rifle chambered for it, instead of the standard .223 R. it have a slightly longer neck.
So if you shoot a 5.56 case in the 223 R chamber your pressure will be higher, due to the neck jamming into the shorter neck chamber of the .223.
However you may shoot the 223 case in the 5.56 without issue.
That is why you see the warning on 5.56 ammo too not fire it in a .223 chambered rifle.
As for primer, they both can use the same primers. It is just that the rifles the fire the 5.56 will have slighter higher pressure, so a harder primer is suggested i.e. Rem 7.5, CCI 41 or a couple others with thicker cups material, to stop piercing and in the case of a AR, what is known as slam fire, where the bolt slamming shut can cause the primer to fire and set the round off.
Just keep your brass for either chamber, if you have both, separate and use it only in the correct chamber dimensions. Bill K
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  #3  
Old 03-31-2018, 02:44 PM
squirrel_slayer squirrel_slayer is offline
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kinda lost me but i'll chime in with what little I know. .223 rem runs at 55k psi 5.56 runs at 62,366 psi but they are measured at a different standard CIP vs SAMMI.

The brass thickness is missleading. for example LC 5.56 brass has greater capacity than most .223 brass. now 7.62x51 on the other hand this is a valid statement.

The main difference as I understand it is the freebore, lead and lead angle. with 5.56 having a greater volume between the case and bore. this area acts as an expansion chamber. both cartridges are identical externally, without this expansion chamber pressures will go through the roof. thats why if you run 5.56 in a .223 chamber it will result in a overpressure condition.

The inbetween chamberings are a great balance of handeling the pressures and maintaining accuracy. (ie .223 wylde)

I haven't seen any rate of twist tests related to pressure but it's safe to assume that a higher rate of twist will cause more resistance thus increasing pressure. again this is an assumption.
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  #4  
Old 03-31-2018, 03:04 PM
Daryl Daryl is offline
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http://kwk.us/pressures.html

The SAAMI and CIP pezio measurements are taken at slightly different locations, as noted in the text, however this is quite a large difference for the .223 alone between US and Euro pressures, 55,000psi and 62,000 psi.

There is no 5.56 Nato in this chart, not sure why.

The heavier cup primer for the 5.56 is due likely for the same reason they are recommended for the .17 Rem, which operates at a SAAMI pressure of 63,000 SAAMI & 62,000 CIPpsi.
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Last edited by Daryl; 03-31-2018 at 03:06 PM.
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  #5  
Old 03-31-2018, 09:49 PM
pocketshaver pocketshaver is offline
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Quote:
Originally Posted by Daryl View Post
http://kwk.us/pressures.html

The SAAMI and CIP pezio measurements are taken at slightly different locations, as noted in the text, however this is quite a large difference for the .223 alone between US and Euro pressures, 55,000psi and 62,000 psi.

There is no 5.56 Nato in this chart, not sure why.

The heavier cup primer for the 5.56 is due likely for the same reason they are recommended for the .17 Rem, which operates at a SAAMI pressure of 63,000 SAAMI & 62,000 CIPpsi.
Anything I can ever find on the CIP standard for ".223 Remington" is that CIP doesn't believe the .223 Remington is a separate cartridge from 5.56x45 NATO. Meaning, CIP uses the t.56 pressure standard for BOTH.....

Thus when a person buys a box of Italian made .223 Remington, is it actually American SAAMI standard .223 or 5.56x45?
And when a person uses that Italian made, CIP approved and tested .223 Remington in an American made .223 Remington rifle "that's not safe to use with 5.56x45" are they going to blow said rifle up?

Never heard of a CIP loaded .223 Remington blowing up a non 5.56x45 rated gun. Never... to many people use a lot of that CIP standard stuff in standard .223 guns and it works fine..

Best I can actually find is that the NATO standard merely allows a higher range of acceptable pressure deviation. Meaning, standard is 55Kpsi, but they'll allow spikes to 60kpsi all day long.

Strangely no one with a pressure testing rig has EVER been willing to test CIP, SAAMI .223 Remington to NATO or CIP or SAAMI testing procedures. No one wants to even test the above pressure standards to NATO testing methods, or test NATO 5.56x45 to CIP or SAAMI standard testing procedures.

On the throat, the longer throat is supposed to be a feature included in the faster twist rate barrels for .223 Rem. Most long time loaders I have talked to on other forums, say the older slower twist rates cant go past 60 grain bullets, but the new fast twist barrels do well.
Thus when the SAAMI standard for .223 Rem chamber uses the slow twist short bullet throat, it should be impossible to get any accuracy with heavy bullets in a fast twist barrel.
IE based on that if long heavy bullet NEEDS long "5.56x45 military throat" to actually chamber and fire safely..... that the chamber drawing needs to be updated.

Further putting the piss to it, as the English say, is that Savage uses 69 grain Seierra Match Kings for .223 test fire groups. That bullet weight should be impossible without military throat.
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  #6  
Old 04-01-2018, 02:28 AM
squirrel_slayer squirrel_slayer is offline
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the 5.56 throat often isn't desired in a precision gun. it was built with extreme use in mind. the .223 wylde is the more popular middle ground which offers a more generous throat but still plays well with 5.56 spec loads.

as for the heavy bullet argument the bullets shape is more important than the weight. the 69 smk is actually a fairly mild contour'd bullet by todays standard. Savage uses 1:9 twist barrels on most of their .223's and 69gr is often the upper limit in bullet weight you can run.

another good example in bullet design would be the 75gr amax (or now eld-m) and the ol standby 77gr smk. the smk has a tangent ogive and it will play well in a standard .223 throat as long as you have the twist to spin it up (often 1:8 or faster) on the opposite end of the spectrum we have the 75 amax(eld) although it weighs slightly less this bullet has a secant ogive and is much longer than the 77 smk. these bullets will also need more generous throating to really accent their potential. more so than even the 5.56 spec chamber. but cartridge length becomes an issue. they will not work @ standard length (2.26") most run them around 2.45"

there really is alot that goes into it and what might compliment one thing may hurt another.
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  #7  
Old 04-01-2018, 07:17 AM
GrocMax GrocMax is offline
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The thicker harder less sensitive CCI41 primer is the solution to out of battery firing caused by the floating pin during initial trials in the early days. Not pressure related.

Take a look at Western Powders data for the differences between SAAMI and NATO/CIP.
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  #8  
Old 04-01-2018, 02:34 PM
moorepower moorepower is offline
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Quote:
Originally Posted by pocketshaver View Post
Anything I can ever find on the CIP standard for ".223 Remington" is that CIP doesn't believe the .223 Remington is a separate cartridge from 5.56x45 NATO. Meaning, CIP uses the t.56 pressure standard for BOTH.....

Thus when a person buys a box of Italian made .223 Remington, is it actually American SAAMI standard .223 or 5.56x45?
And when a person uses that Italian made, CIP approved and tested .223 Remington in an American made .223 Remington rifle "that's not safe to use with 5.56x45" are they going to blow said rifle up?

Never heard of a CIP loaded .223 Remington blowing up a non 5.56x45 rated gun. Never... to many people use a lot of that CIP standard stuff in standard .223 guns and it works fine..

Best I can actually find is that the NATO standard merely allows a higher range of acceptable pressure deviation. Meaning, standard is 55Kpsi, but they'll allow spikes to 60kpsi all day long.

Strangely no one with a pressure testing rig has EVER been willing to test CIP, SAAMI .223 Remington to NATO or CIP or SAAMI testing procedures. No one wants to even test the above pressure standards to NATO testing methods, or test NATO 5.56x45 to CIP or SAAMI standard testing procedures.

On the throat, the longer throat is supposed to be a feature included in the faster twist rate barrels for .223 Rem. Most long time loaders I have talked to on other forums, say the older slower twist rates cant go past 60 grain bullets, but the new fast twist barrels do well.
Thus when the SAAMI standard for .223 Rem chamber uses the slow twist short bullet throat, it should be impossible to get any accuracy with heavy bullets in a fast twist barrel.
IE based on that if long heavy bullet NEEDS long "5.56x45 military throat" to actually chamber and fire safely..... that the chamber drawing needs to be updated.

Further putting the piss to it, as the English say, is that Savage uses 69 grain Seierra Match Kings for .223 test fire groups. That bullet weight should be impossible without military throat.
Actually Hornady test both, but the C.I.P. Is in a 20” barrel. Western powder tests both but not as many powders are used.
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  #9  
Old 04-01-2018, 07:30 PM
pocketshaver pocketshaver is offline
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CIP is not NATO, based on actual testing procedure I can see. Use same pressure..
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  #10  
Old 04-01-2018, 08:01 PM
Bill K Bill K is offline
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Default ,223 or is it 5.56

Quote:
Originally Posted by pocketshaver View Post
CIP is not NATO, based on actual testing procedure I can see. Use same pressure..
No matter the testing with the same pressure. If you read and follow ammo companies warnings, 5.56 ammo should not be fired in standard .223 chambers, as it will give higher pressure and can be harmful to the weapon and the shooter. But you do as you desire and shoot whatever and however you want. I know I play safe and sound, in factory and reloaded ammo. Bill K
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