r34skyline
CGN Ultra frequent flyer
Raw data. I like it.
And as far as the alloy goes material composition is one thing. the correct heat treat is another.
Then there is the surface finish and the quality of that as well.
CQA made of inferior alumenium
- Thread starter zain
- Start date
Raw data. I like it.
And as far as the alloy goes material composition is one thing. the correct heat treat is another.
Then there is the surface finish and the quality of that as well.
ThatM305Guy
CGN frequent flyer
- Location
- North Texas
Also forging vs billet grain structure. From the source that data comes from apparently there was a specific type of corrosion (off the top of my head I cant remember the correct term) in Vietnam that forged 6061 was susceptible to because of the grain structure. Which is unusual because 6061 typically has better corrosion resistance over 7075.
*Edit*
"In Vietnam, the original M16 used aluminum receivers made of 6061 aluminum originally, but later switched to 7075 aluminum. The reason given was that when the receiver was forged from 6061 aluminum, the forging process made them prone to intergranular exfoliation in environments of high temperature and humidity, such as that found in the jungles of Vietnam, especially when combined with human sweat. Upon a suggestion by Eugene Stoner, the receivers were changed to use 7075 aluminum instead."
http://firearmshistory.########.com/2014/10/metals-used-in-firearms-iv.html?m=1
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here is the link
https://nationalinterest.org/blog/buzz/china-cloned-m16-meet-norinco-cq-rifle-40707
i also copy paste the relevant section
There are other differences. The CQ uses Type 6000-series aluminum alloy, which is lightweight but weaker and less corrosion-resistant than the M16A1’s Type 7075 aluminum. It is also less expensive and easier to mill. Internally, the CQ’s barrel features a 1 in 12-inch right-handed rifling twist rate. Rifling is designed to induce spin—and thus stability—on a bullet as it exits the barrel, and the rifling must match the particular bullet. In the CQ’s case, the 1 in 12-inch rifling is meant to stabilize the older 55 grain M193 round, not the more recent 62-grain SS109 armor piercing round or more recent bullets. Although the CQ will fire all of them, ballistic performance over distance will be degraded.
https://nationalinterest.org/blog/buzz/china-cloned-m16-meet-norinco-cq-rifle-40707
i also copy paste the relevant section
There are other differences. The CQ uses Type 6000-series aluminum alloy, which is lightweight but weaker and less corrosion-resistant than the M16A1’s Type 7075 aluminum. It is also less expensive and easier to mill. Internally, the CQ’s barrel features a 1 in 12-inch right-handed rifling twist rate. Rifling is designed to induce spin—and thus stability—on a bullet as it exits the barrel, and the rifling must match the particular bullet. In the CQ’s case, the 1 in 12-inch rifling is meant to stabilize the older 55 grain M193 round, not the more recent 62-grain SS109 armor piercing round or more recent bullets. Although the CQ will fire all of them, ballistic performance over distance will be degraded.
