I am looking up 223 loads on QuickLOAD. I have noticed that there are 2 different 223 loads. SAAMI has much lower pressures. Not sure what to do. What or why is there a difference. I am reloading for a 1:7 223 Wylde. I am not afraid of pushing it a little bit but, don't want to screw it up with too much pressure.

Is it just that SAAMI keeps it on the tame side?

You didn't say if you are shooting a bolt gun or AR/semi-auto. I have a friend that played with the Wylde chamber in both. Stoner designed the X-15 to use the Wylde chamber and the 223/5.56 cartridge was designed specifically for that gun. With the adoption of the M-16 and assignment to Colt and others the NATO chamber is slightly different.

Wylde is THE chamber for a gas gun to run at the higher pressures of 5.56 NATO, 223 factory is always loaded milder. (One of my super accurate single shot bolt guns (Cooper 21) has the Wylde chamber. To get the accuracy I load to touch the lands, and that is .14 longer that SAAMI OAL,( also too long for an AR magazine.) But my accuracy runs .089 MOA out to 300 yards! (basically 1/4" groups at 300 yards!)

I have found several guns shoot the Sierra Loading Manual accuracy load best, once I find the COAL that that rifle likes. But in AR's these are often way too long for a magazine and are hand fed one at a time!

Part of the "Long Lead" is for dirt control in combat! But it also allows for longer seating and more powder at lower pressures.

Ivan

PWS AR with a 16" barrel. Piston system not DI

I purchased the QuickLOAD to see about using a better variety of powders that the regular loading manuals don't list but, work just fine.

QuickLOAD isn't really a data book per se, so it's not really possible to "look up" loads. Rather, it attempts to calculate internal ballistics. It's not a substitute for tests. However, at least one bullet manufacturer freely admits their published data comes out of QuickLOAD. I have the program, use it often and it scratches my analytical itch. I don't consider it the last word and always compare it against published load data.

In the QuickLOAD pulldown menu, .223 Rem and .223 Rem (SAAMI) are both listed. They are listed at 62,366 PSI MAP and 55,000 PSI MAP respectively. That's quite a difference all right. The key is that the higher pressure also shows a CIP Piezo measurement method and the lower pressure shows SAAMI Piezo. CIP is the European version of SAAMI and it wouldn't be too surprising to learn their standards are different.

So having said all that, I'd keep a close eye on published loading books. And yes, I know; they don't aways agree either.

I checked the 5.56 and it mirrors the 223 Rem pressure. The SAAMI is closer to what I am finding in other locations.

Not exactly. The case capacity, using the 5.56 NATO spec, has a slightly smaller case capacity than the 223's.

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And neither is a reloading manual.

Due to the number and variability of components in both the firearm and cartridge, testing and validation is required regardless of where your data comes from.

At the end of the day reloading manuals and simulation programs are just tools to help use make informed decisions.

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Ruggy

If you look at actual brass as formed by various companies, there isn't much evidence that .223 brass has greater case capacity than 5.56 x 45 mm. You also have to recall that the .223 round was designed originally as the military round. The history of military cartridges becoming civilian favorites likely led to the mass marketing of the round. Different name? Metric cartridges historically hadn't done all that well in our commercial market.

This came up sometime back and I weighed a slew of brands of cases. IIRC, the only head stamp that had any noticeable difference from the mean was Winchester. So yeah, certain brands may be different, but unless you're pursuing bleeding edge velocities, not an issue.

Moore, the conversation was about what QuickLoads says.

Though I haven't taken the time to do my own measurements, from what I've read from other sources I agree with you.

For some reason QuickLoads has it's own opinion.

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