Sunday, November 18, 2018

Ballistic Gack: Trajectories

The AR-15 platform chambered in 5.56mm NATO with a 16" barrel is the default firearm in America today.
50 grain Hornady V-Max starting at 3080fps. Three different zeros. Sights 1.5" above bore. All data collected from the on-line Hornady Ballistic Calculator

55 grain Hornady soft point with cannelure starting at 2900fps. Three different zeros. Sights 1.5" above bore.

60 grain Hornady V-Max starting at 2790fps. Three different zeros. Sights 1.5" above bore.
Three different weights with 200 yard zero over-plotted. Max range reduced to increase resolution between offerings.
Same as above but plotted out to 400 yards.
Summary: 
  • Once zeroed in, the differences in trajectory are small out to 250 yards.
  • The slippery 60 grain V-Max never overcomes it disadvantage in starting speed, at least not within the first 400 yards.
  • The 50gr V-Max stays above 1700fps past 400 yards. 1700fps is sometimes used as the threshold for expansion or mushrooming for rifle bullets.
  • The 55gr soft point stays above 1700fps to 325 yards
  • The 60gr V-Max stays above 1700fps to 350 yards.
  • Initial velocities were fudge-factored down from Hodgdon reloading data for H-335 for the respective weight bullets and a 24" barrel.
  • On a short range, a 200 yard zero can be approximated by "zeroing" at 1.0 inch above line-of-sight at fifty yards or 2 inches above line of sight at 100 yards.

2 comments:

  1. Joe, have you ever tried the 53gr V-max? I haven't had a chance to shoot it much but it seems like a nice compromise for weight vs BC, especially with the cute little boat-tail.

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    Replies
    1. I have not tried them. I am still pretty new to this 5.56X45mm .223 Rem game.

      I am a whiz on the computer, though...and you should see my ninja moves at the local mall.

      One thing that was not discussed was wind. Gravity is a constant and is easy to compensate for if you have a range finder and time. Wind is a fickle bitch.

      My interests are more along the lines of the quick-and-dirty. Can a man with old eyes, shooting from field positions with a non-magnifying scope. I am most likely to NEED a firearm when the target is within fifty feet as opposed to 300 yards.

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