New Army "Caliber Configuration Study"

[cory]

Alright so I just took some measurements and ran some numbers. I think we can safely assume negligible change to empty magazine weight.

Let's compare a LC M855 round to a Hornady 123gr SST.

Using a RCBS 5-0-5 scale the weight of an individual round is as follows:

M855 - 188gr +-1gr
123gr SST - 271gr +-1gr

from a google search I used 1gr = 0.000142857143 lbm

Converting grs to lbm then multiplying by the current minimum combat load of 180 rounds we're looking at:

M855 180x = 4.83lbm
123gr SST 180x = 6.97lbm

While we're at it let's look at a load of 300 rounds.

M855 x300 = 8.06lbm
123gr SST x300 = 11.61lbm

So worst case we're looking at an ~3.5lbm addition to the combat load to give our grunts a much more capable carbine.

(If I've screwed my math up somewhere please let me know.)

Conclusion:
IMHO I think we can rule out significant addition to combat fatigue as a deciding factor.


Verification using a cheap food scale:
Winchester M855 x30 = 12.91oz
x10
M855 x300 = 129.1oz
/16
M855 x300= 8.07lbm