Reloaded Military Brass in an XCR
- Thread starter Gobc
- Start date
Again, You will not find a 'match' or tight tollerance chamber cut on anything but a custom gun, by a custom gunsmith - so the whole question of 'does my .223 marked barrel shoot 5.56' won't even be asked.
Again with the pressure trace testing - this is not accurate enough testing to verify the arguement of pressure differences and certainly does not account for the different approaches to testing carried out by SAMMI and NATO.
Simplest thing is to look at this picture. 5.56 is loaded to accomodate the long throat, so pressure spikes in a saami-spec .223 chamber:
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I've said this over and over - 5.56 has a longer throated chamber to accomodate reliable feeding.
You will not find ANY NATO or otherwise spec loaded 5.56mm ammo that has the bullet loaded out so that the round is longer than the 2.260" oal (in fact it is likely to be much shorter around 2.250 - 2.240" oal)
This fact alone does not lead to the conclusion that pressures are dangerous, never mind elevated....
Again this has be de-bunked countless times. While there are variations in brass weight from manufacturer to manufacturer, some of this may or may not be attributable to slight variations in total volume. You are just as likely to come across commercial brass that has less volume over nato brass as vise versa - The kicker here is that while it makes for good reading, the practical differences in cases can be so minute that they simply don't matter - If you don't believe it, try testing some of this theory like I have done....
1) that's just incorrect. Conformal transducers are quite accurate and repeatable. Of course 5.56 runs at a higher pressure, even in a 5.56 chamber - anyone can see that when a 5.56 AR (smaller gas port, e.g., Noveske) is under-gassed running 223, and the pressure goes up again in a saami-spec 223 chamber. The transducer simply measures the difference for us and tells us if it does or does not exceed spec - it does.
2) it hasn't been "debunked" when I use language like "A lot of 5.56 ... but not all". It's a statement of fact. I've measured several commercial 223 brands and several 5.56 manufacturers (differing markings) with the water weight method and found smaller volumes in the 5.56. I'm well aware that it isn't universal - for example, commercial Lapua at one point had a relatively small volume - hence the "not all" statement.
We can certainly agree that most "223" chambers are cut generously to avoid this issue - but not all, and that makes running 5.56 in a 223 chamber questionable at best.
for clarity,
What I wrote:
"Again with the pressure trace testing - this is not accurate enough testing to verify the arguement of pressure differences and certainly does not account for the different approaches to testing carried out by SAMMI and NATO.|"
What I should have wrote:
...this is not accurate enough testing to verify the blanket arguement that pressure differences using 5.56 spec'd ammo in a .223 chambers is hazardous.
While I agree with you in general terms, pressures could and can rise, you and I both know there is some '.223' spec'd ammo that is just as hot as any '5.56' out there...
What I wrote:
"Again with the pressure trace testing - this is not accurate enough testing to verify the arguement of pressure differences and certainly does not account for the different approaches to testing carried out by SAMMI and NATO.|"
What I should have wrote:
...this is not accurate enough testing to verify the blanket arguement that pressure differences using 5.56 spec'd ammo in a .223 chambers is hazardous.
While I agree with you in general terms, pressures could and can rise, you and I both know there is some '.223' spec'd ammo that is just as hot as any '5.56' out there...
