.223 vs 5.56

[mpmarty]

+ 100% Larry has nailed it.

[khmer6]

Completely agreed. When was the last time you saw 5.56 reloading dies? If it chambers shoot it. It might have a shorter throat or slower twist, so check to see how heavy you can go on the projectile

[Artful]

The rifle was NOT "designed for" any particular cartridge.

The factory takes a STANDARD action, and screws-on a STANDARD .22-caliber barrel, and chambers it with a STANDARD reamer for the cartridge involved. The only "design" component is the marketing sector trying to "design" a package that will sell on the market.

The actions ARE designed (and over-engineered) to contain pressure variations FAR higher than the piddling differences between the various .223/5.56 loadings.

So which one is the standard reamer?
http://ar15barrels.com/data/223-556.pdf
PTG 223 Rem Match
Clymer 223 Rem
PTG 223 Rem
JGS 223 Wylde
JGS 5.56 Compass Lake
JGS 5.56 Nato
PTG 5.56 Nato
Clymer 5.56 Nato

[BruceB]

I prefer to use what works based on actual experience and comprehensive testing. But then that's just me I guess........

Larry Gibson

No, Larry, it's not just you. There's quite a bunch of us who accept the REALITY of the situations regarding the .223/5.56 and .308/7.62 NATO. All the lawyer-generated crapola in the world will not change the FACTS.... which are that the cartridges are simply interchangeable.... barring such things as the bullet weight vs rifling twist consideration.

Personally, I never went to the extent which you did, obtaining the Oehler instrumentation to take pressure readings. Instead, a considerable succession of rifles over the decades have offered their own testimony.

I'm quite satisfied that , over the fifty-odd years of experience, I have NOT placed either my rifles or my body parts in any jeopardy whatever.... and I have benefitted in the bargain with excellent performance and long loading lives from my components.

Maybe someday the truth will get around?

[Gohon]

I wouldn't call a 10,000 CUP difference a piddling difference in pressure. As for internet experts, if you're posting or reading this forum then you are feeding at the same trough. Funny how some constantly tell others to be safe and follow the data when reloading, but turn right around and tell the same people to ignore the manufactures warning concerning what not to shoot in their guns.

[MaryB]

Would be interesting for someone to measure barrel diameters over the entire length and see if the chamber area is any thicker on a 5.56 savage barrel compared to the .223 axis barrel, chances are none, then drop a 5.56 reamer in and see if it fits, that is the only spot there will probably be a difference. I would guess the barrels are designed to handle 5.56 and are only reamed to .223

[Larry Gibson]

Gohon

There is not a 10,000 C.U.P. "difference". You are either comparing the older way of measuring with the newer way (peizo-transducers) of measuring pressure or you've some wrong internet figures. When measured on the same equipment (the peizo-transducer or strain gauge equipment) the factory adhered to MAP (Maximum Average Pressure) for the .223 is 55,000 psi. On the same equipment the MAP is 60,000 psi (60K for the gas case mouth transducer and 62K for a standard peizo-transducer) for the 5.56 NATO. And all such factory and military loaded cartridges are not loaded to the MAP, actually most aren't loaded to MAP. As I've stated, I have measured quite a bit of both types of ammunition in the same test barrel with the same chamber (a tight SAAMI minimum spec chamber) and can show you .223 factory ammo that has a higher psi than some 5.56 military ammo so I am not depending on internet "information" but 1st hand data from actual testing.

I've also been loading my own .223 to old Sierra, Hornady, Lyman, etc., data levels that were for the .223/5.56 cartridge (newer data in those manuals is lower for the .223 as it now adheres to the SAAMI MAP) and they test out in the 58 - 60,000 psi. Those are quite safe levels in any modern action the .223 may be chambered in. Understand that when the industry says not to shoot 5.56 in .223 chambers because of potentially higher pressures they simply mean pressures above the SAAMI MAP which is there self proscribed limit.

Now, let me ask a simple question since you brought up C.U.P. pressure measurement; the SAAMI C.U.P. MAP for both the .223 and the .308W is 52,000. Yet the SAAMI peizo-transducer psi for the .223 is 55,000 and for the .308W it is 62,000 psi. So why is not the psi for the peizo-transducer MAPs the same for both cartridges as it is with the C.U.P. measurements for both cartridges?

Don't worry about the answer as SAAMI doesn't have a good answer either. Point is there is no reason the .223 can not be safe at 60,000 psi and, in fact, it is quite safe at that psi......which is what psi the top end 5.56 loads generate.

Larry Gibson

[steve4102]

I wouldn't call a 10,000 CUP difference a piddling difference in pressure. .

Neither would I, but the difference is not 10,000 CUP it is actually a mere 7K PSI. The 223 has a MAP of 55K psi, the 5.56 has an MAP of 62K psi. Not enough to blow up or even damage any modern action rifle.

Here is a little Pressure test done by Barnes bullets.
Note: there is no earth shattering dangerous pressures involved. Nothing a Savage 223 can't handle.



My point in posting the Savage warning was only to inform the OP that having a conversation with Savage about handloads could end up with a voided warranty.

[Ghost101]

The Savage did fine this morning with both .223 and 5.56. I'm glad that I asked, because I learned more then I expected.
Thank you

Ghost101

[Larry Gibson]

As we used to say when I was an LEO investigator; case closed.

Larry Gibson