Monday, November 24, 2014

Common Zeros at Common Ranges 1

I have an idea for an experiment. Based on the concept of "not being on paper at 100 yards."
Take the most common zeros for AR15 platform rifles:
300 - USMC
50/200 - IBZ
100 - RIBZ


Facts
My hypothesis is that at 50 yards, which zero you use will not matter. For the sake of exploring this, lets look at the facts.

At 100 yards, the zeros will perform as follows:
USMC - shots will be 3 inches high.
IBZ - shots will strike 1 inch high.
RIBZ - shots will strike at the point of aim (POA).

Each click of elevation adjustment on a 6/3 detachable carry handle will move the sights 1/2 MOA.
1/2 MOA at 50 yards is 0.25 inches.


Extrapolation
Using these facts, the following information can be extrapolated:

1. IBZ will be on the money.
POA = POI

2. RIBZ (100 yard zero) would be two clicks down from IBZ.
Two clicks = 1 MOA.
1 MOA at 50 yards = 0.5 inches.
Shots would impact a half-inch low at 50 yards.

3. USMC (300 yard zero) would be four clicks up from IBZ.
Four clicks = 2 MOA.
2 MOA at 50 yards = 1 inch.
Shots would impact 1 inch high at 50 yards.


-----

Summary:
100-yard zero would impact a half inch low at 50 yards.
200-yard zero would impact at point of aim at 50 yards.
300-yard zero would impact an inch high at 50 yards.

Doesn't sound like a huge difference to me.


Now I need to go to the range and test it.

.

No comments:

Post a Comment

Your comment will be displayed after approval.
Approval depends on what you say and how you say it.