What's the hunting caliber easiest to get in 2021?

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[–] • 1 pt

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The most common refrain is that 5.56 is significantly higher pressure than .223. But that difference is almost entirely due to different testing methods.

The .223 round is civilian, so it's measured by SAAMI. They say they it is 55kpsi.

The 5.56 is NATO, so they measure the pressure. They have been using a testing methodology called EPVAT. That has the pressure sensor in a different place than the SAAMI test. NATO's EPVAT gives the pressure at 62kpsi.

NATO has also recently started using a different testing method called SCATP. The SCATP test is designed to check pressure in the same way that the SAAMI test does it. The pressure of the 5.56 round tested by the SCATP method is 55kpsi.

So the exact same 5.56 round measured by EPVAT is 62kpsi, and the exact same 5.56 round measured by SCATP is 55kpsi. The difference is the testing methodology and how the pressure is measured. In the NATO test that is designed to be the same as the SAAMI test, 5.56 tests as 55kpsi and the .223 tests as 55kpsi.

There are differences between the two rounds, but the pressure is a lot closer than what most people will tell you.

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[–] • 0 pt

Excellent! And besides, ar parts are so cheap, who gives a shit. Shut up and shoot.😁

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[+] [deleted] • 0 pt

[–] • 0 pt

> I still wouldnt shoot a 5.56 out of .223 gun.

No, the rounds are different and I don't mean to imply that they are identical. Only that the spec of the difference in pressure is overblown. (Ahh, see what I did there?? "Overblown"!) Something like the .223 Wylde chamber is specifically made to accept either round.

Rounds can be different by manufacturer and can be different by product line. But on an apple to apple basis I'd compare two similar rounds. Like the Federal with 55 grain bullet and the Federal with 55 grain bullet. The .223 is listed as Muzzle Velocity of 3240fps and the 5.56 is listed as 3165fps. In that round with the same bullet mass, the .223 has a higher muzzle velocity.

Now, I won't try to tell you what I don't know. So below is my understandings and/or speculations;

I understand that SAAMI is more rigorous on testing and insisting on compliance with published standards whereas making a NATO round is more free-for-all. That leads to some makers (or lines within a brand) to 'overcook' their 5.56 rounds to deliberately make them shoot hotter. That means that some lines offer the equivalent of +P rounds in the 5.56 products that are beyond the published pressure spec.

There is also a difference in the way the primer attaches to the case in .223 vs 5.56 rounds. It could be that one is more rigorous than the other and that 5.56 is less likely to fail with these '+P' pressures.

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