Why 10% less powder for IVI/LC military brass???
- Thread starter Brianma65
- Start date
I did a similar test with hirtenberger .308 vs. fed commercial (see post in "ammo" section). My results were the same as the op. The hirt cases actually on average had 1.5 grain more capacity.
Not being one to just go along with the parrots, I will now and into the future always do a case capacity test regarding military brass.
Not being one to just go along with the parrots, I will now and into the future always do a case capacity test regarding military brass.
All fired in the same rifle or different rifles? If it's from different rifles then just measuring capacity might not be the entire story.
Basically, it's not only about the capacity of the brass, it's also related to the capacity of your chamber. If the walls are thicker on one make of brass, then that extra mass uses some of the available space in the chamber when you fire that round and if it's enough difference it might affect pressures. It would be the same as having a tighter chamber.
Lake City 5.56 cases are made of harder brass, and Lake City 7.62 cases are made of thicker brass and only the 7.62 cases are recommended to reduce the load vs commercial .308 cases.
I will assume since the U.S. and Canada uses the same type M16 rifle that your 5.56 case manufacturing would be the same. The harder brass requirement for the 5.56 case came about after the 1968 Congressional hearings on the M16 jamming problems.
Below from the book "The Black Rifle: M16 Retrospective"
How Hard is Your Brass? 5.56 and .223 Rem Base Hardness Tests
http://bulletin.accurateshooter.com/2014/05/how-hard-is-your-brass-5-56-and-223-rem-base-hardness-tests/
Bottom line, check your military 7.62 NATO cases for capacity, there might be a chance that newer cases are made from the same type brass as 5.56 cases. Each country can be making cases to their own requirements and the capacity can vary.
I will assume since the U.S. and Canada uses the same type M16 rifle that your 5.56 case manufacturing would be the same. The harder brass requirement for the 5.56 case came about after the 1968 Congressional hearings on the M16 jamming problems.
Below from the book "The Black Rifle: M16 Retrospective"
How Hard is Your Brass? 5.56 and .223 Rem Base Hardness Tests
http://bulletin.accurateshooter.com/2014/05/how-hard-is-your-brass-5-56-and-223-rem-base-hardness-tests/
Bottom line, check your military 7.62 NATO cases for capacity, there might be a chance that newer cases are made from the same type brass as 5.56 cases. Each country can be making cases to their own requirements and the capacity can vary.
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