Does anyone have a workable MV for M855 out of 14.5"-16" barrel lengths?
Want something for ballistic apps and I can never get my chrono to work.
Thanks,
Greg
edit: And the temp if you would have that too. Thanks again.
Some ballistic apps will "reverse engineer" your MV based on your zero distance and bullet drop at an appreciable second distance.
I did a 100-yard zero then measured bullet drop at 300-yards, input it into Strelok and was making first shot hits on steel at 500-yards using the table it computed.
Just my $0.02...
https://apps.dtic.mil/sti/pdfs/ADA544533.pdf
Start at pg 48 for info.
This data is based on true mil spec rifle and ammunition. While I don't have the source data, it is most likely that this is the approved .mil ballistic data which is not necessarily based on calculations from ballistics programs but from actual test data.
A couple of things:
If you use a true Mil-Spec Rifle with true Mil-Spec ammo you will get predictable results almost every time.
When we start deviating from the above is when things start to get interesting. There are a lot of variables that will effect the MV out of your own personal 16 inch rifle.
Of course I understand the use of ballistic programs as a starting point, but you will still need to go out and verify.
https://shooterscalculator.com/ballistic-trajectory-chart.php?t=1fb30810
This is pre populated with 16 inch data for M855. There is some variation in the BC as compared to other sources but it doesn't affect the end results too much. The MV is listed as 2900 here and there is a significant difference noted at longer ranges as compared to a MV of 2800 which is referenced in the sdi.edu link above. Also with sight height.
When you start playing with the numbers, it can make your head hurt. If you have a range available always best to go see what happens in real life.
If you use another ballistics calculator, make sure you use the G7 coefficient.
As an aside:
I have a 20 inch are with a scope on it. The reticle has generic BDC on the reticle which corresponds nearly 100% to M193 ammo. If you input the data for M193 and Mk262 you will get significant deviations in trajectory.
In real life, once this particular rifle is zeroed for each round the BDC works perfectly for both out to 400yds. Go figure.