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Old 07-20-2019, 06:10 AM
Desert Mariner Desert Mariner is offline
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Join Date: Oct 2018
Location: Texas
Posts: 91

Originally Posted by nuke11 View Post
Try using Federal American Eagle .223 55 grain and 62 grain.

55 grain: BC .269
62 grain: BC .307
Without rounding, even these calculate lower than the E=15 listed in TM 1-1:

55gr FMJ @987mps comes to E=14.5
62gr FMJBT @920mps comes to E=13.5

I'd have to treat the BC as G1 since they don't specify and that would align with other 5.56 rounds.

The S&B 5.56 rounds I've checked include (these BCs are all G7):
55gr FMJ @1006mps BC=0.143 E=14.8
62gr DIM @945mps BC=0.143 E=13.9
63gr Tracer @915mps BC=0.143 E=13.4
69gr HPBT @920mps BC=0.148 E=13.5

E-factors shown calculated based on listed MV of cartridge, they will vary when barrel length of actual weapon is included.

Side note: I have been attempting to limit the number of ammo producers in keeping with the Project's need for secrecy and to simplify logistics.
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