dan brothers
New member
I'm on the outside looking in.. on this one... BUT...
If the nato case is thicker...preventing less powder... then how do they make them hotter than a 223...?
Alot of consumers are going to mix this one up big time...
I got it... it's not the powder.. it's the leade space....
Chambers cut to .223 Remington specifications have a shorter leade (throat) area as well as slightly shorter headspace dimensions compared to 5.56 NATO "military" chamber specs, which contributes to the pressure issues.
While the 5.56 NATO and .223 Remington cartridges are very similar, they are not identical. Military cases are made with thicker brass in the web area than commercial cases, which reduces the powder capacity (an important consideration for handloaders), and the NATO specification allows a higher chamber pressure. Test barrels made for 5.56 NATO cartridge measure chamber pressure at the case mouth, as opposed to the SAAMI (Sporting Arms and Ammunition Manufacturer’s Institute) location. This difference accounts for upwards of 20,000+ psi difference in pressure measurements. That means that advertised pressure of 58,000 psi for 5.56 NATO, is around 78,000 psi tested in .223 Remington test barrels. SAAMI .223 Rem Proof MAP is 78,500 psi so every 5.56 NATO round fired is basically a proof load, potentially very dangerous.
http://www.cheaperthandirt.com/mediapages/ArticleDetail.aspx?mediaid=316
If the nato case is thicker...preventing less powder... then how do they make them hotter than a 223...?
Alot of consumers are going to mix this one up big time...
I got it... it's not the powder.. it's the leade space....
Chambers cut to .223 Remington specifications have a shorter leade (throat) area as well as slightly shorter headspace dimensions compared to 5.56 NATO "military" chamber specs, which contributes to the pressure issues.
While the 5.56 NATO and .223 Remington cartridges are very similar, they are not identical. Military cases are made with thicker brass in the web area than commercial cases, which reduces the powder capacity (an important consideration for handloaders), and the NATO specification allows a higher chamber pressure. Test barrels made for 5.56 NATO cartridge measure chamber pressure at the case mouth, as opposed to the SAAMI (Sporting Arms and Ammunition Manufacturer’s Institute) location. This difference accounts for upwards of 20,000+ psi difference in pressure measurements. That means that advertised pressure of 58,000 psi for 5.56 NATO, is around 78,000 psi tested in .223 Remington test barrels. SAAMI .223 Rem Proof MAP is 78,500 psi so every 5.56 NATO round fired is basically a proof load, potentially very dangerous.
http://www.cheaperthandirt.com/mediapages/ArticleDetail.aspx?mediaid=316
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