14.5" barrel zero/traj for 50yd zero for various cartridges

**1168** · 09-15-21, 01:38

Originally Posted by vicious_cb

FYI the 50/200 yd zero is bulls*** for any real duty/defensive cartridges. Once you plug in the actual data like real BCs from Bryan Litz and realistic velocities out of 14.5"s or shorter barrels you'll find things are closer to 50/125 or 50/150.

What optic height are you plugging in?

**vicious_cb** · 09-15-21, 04:27

Originally Posted by 1168

What optic height are you plugging in?

1.9" for RDS
1.7" for LPVO

**1168** · 09-15-21, 05:26

Originally Posted by vicious_cb

1.9" for RDS
1.7" for LPVO

I’ve been adding an inch for the height of the rail over the bore. So, 2.9” for Scalarworks/T2. Seems to work well. I don’t know of any loads that are as far off as you’re reporting in a 12.5”-14.5”, or even an 11.5”. Furthest off I could come up with (on the calculator) was 170yds for a slow load from an 11.5”. For my 12.3”, 50/200 is spot on for 68-70gr loads, and m855 crosses around 220.

**99Bubba** · 09-15-21, 06:31

Originally Posted by turnburglar

You guys are funny.....

Here's the math.

Strelok Pro:

16" AR
2850 FPS
62gr FMJ at 0.271 G1
50 yard zero

100 +1.3"
150 +1.2"
200 -0.4"
250 -3.8"
300 -9.1"
350 -16.7"
400 -26.8"
450 -39.9"
500 -56.6"

To the OP:

If you are shooting with iron sights, zero at 50 and your dead on at 200. With iron's anyways you would never be able to tell if the bullet was 6" high or low much less 1/2".

thank you

**99Bubba** · 09-15-21, 06:37

thank you...I will have to see...I'll just zero at 50 and see when they print at 200 when the range opens (it's closed due to safe concerns as bullets were landing outside of the berms)...

**AndyLate** · 09-15-21, 07:11

Originally Posted by turnburglar

~SNIP~

To the OP:

If you are shooting with iron sights, zero at 50 and your dead on at 200. With iron's anyways you would never be able to tell if the bullet was 6" high or low much less 1/2".

I was certain this was true and ran the numbers in a ballistic calculator to confirm. I came up with a different trajectory because I left the sight height correct for a bolt action rifle. It was a good reminder to me that the ammo manufacturers' advertised trajectories are plotted for a much lower sight height than an AR has.

Andy

**99Bubba** · 09-15-21, 07:19

...A graph for a 14.5" barrel M4 showing the trajectory with a 50 yd zero with a 100 yd zero for M193 to see the difference would be great...if one has a graph to share...

**Mjolnir** · 09-15-21, 08:41

Why isn’t “everyone” running 2.5” above the bore?

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**1168** · 09-15-21, 09:10

Originally Posted by 99Bubba

...A graph for a 14.5" barrel M4 showing the trajectory with a 50 yd zero with a 100 yd zero for M193 to see the difference would be great...if one has a graph to share...

From Ballistic AE
3025fps

0 -2.5
25 -1.1
50 zero
75 0.9
100 1.4
125 1.7
150 1.6
175 1.2
200 .3

0 -2.5
25 -1.5
50 -.7
75 -.2
100 zero
125 -.1
150 -.5
175 -1.3
200 -2.5

Originally Posted by Mjolnir

Why isn’t “everyone” running 2.5” above the bore?

Sent from my iPhone using Tapatalk

Tall mounts. I use 2.9” over bore in the calculator for ~1.9” mounts.