Posted: 8/18/2004 11:22:51 AM EST
I have a Armalite AR-15 M4 (A3?) waiting for me to pick up after the ban sunsets.
[It has a fixed front sight and an eotech red dot mounted with the carry handle removed.]
Have also put a way a Ciener .22 Conversion unit.
Plan to use the .22 to train at my local range (which does not allow "Rifle" ammo), and as time and $$ permit, get used to the .223 at the NRA range which handles "anything".
My question is about the relative POI & POA for the .22 vs the .223.
I expect that the POI will be quite different for the two calibers (even at 25 Yards).
Is it feasible to set up the EOTec so that POI = POA for the .22
Using the fixed front zeroed in with the sight on the Carry Handle (after removing the EOTec)
when shooting .223 ???
Or Vice Versa ??
yes you could dial in the irond for .22 and the Eotech for .223 or vice versa. I would not recomend that. What I did was sight everything in for.223 so I could co-witnness, and deal with the .22 shooting alittle low. You will get used to it and can just compinsate for the .22 drop.
Works freat that way for me..
Can anyone say just how much difference ("a little low" ) might be???
Say at 25 Yards ??
at 25 yards I would guess about 3inches..
In my experience with iron sights, the difference between .22 POI at 25yds vs .223 POI when zeroed for .223 at 25yds isn't all that much. Minute of tin can anyway. This is, however, quite a long ways from the 50yd/200m .223 zero (IBZ) that's recommended. (The 25-yard zero setting on the handle is the same as the 400m zero, which is I think 5 MOA higher than the 200m setting on the handle.) At 50 yards the difference is quite a bit more, but I don't remember exactly how much.
What I would do in your situation is zero the EOTech for 50yds with .223 ammo. Then I'd put on the detachable handle and set it up for the groups.msn.com/TheMarylandAR15ShootersSite/improvedbattlesightzero.msnw]Improved Battlesight Zero]. Use this setting for your .223 shooting.
Then I'd take the .22 kit and find out where to set the distance ring for various distances with it. For 25 yards it should be right around the "4" on the dial. I'm going to guess 50 yards is somewhere between "5" and "6" on the dial.
OK. I ran the ballistics for you.
Using the sight settings for 50 yards with Q3131A (3170fps from a 16" barrel, BC = .266) and then firing Fed. 550 pack ammo (36gr, 1255fps, BC = .126) :
It says the sight setting for the 50-yard .223 zero is 5.839 MOA and the setting for a 50-yard .22LR zero is 10.782 MOA, which is about 5 MOA or 20 clicks on scope with 1/4 minute clicks or I think 10 clicks on the detachable handle. A 25-yard .22LR zero is 12.769 MOA or about another 2 MOA. Using the 25-yard .223 zero, 10.372, gives .6 low at 25 yards with the .22LR.
I couldn't ask for a more detailed and complete answer to my question>
Now....If I can only understand all that correctly.............
Why is it that the "bullet drop" DECREASES (2.6> 1.8) from 0 to 25 yards
INCREASES 1.8 > 2.6 from 25 to 50 yards
and what is with a 2.6 drop at ZERO Yards?
Wait a minute:
Is this saying that :
There is a 2.6 inch distance from the axis of the barrel to the line of sight
at the muzzel
The POI rises but never quite reaches the line of sight (reaching the peak of its trajectory at 25 yards and then drops away from the the line of sight from then on..................
Just trying to understand your data
(( What S/W generated it ?? ))
Bottom line however, and the answer to mey question:
I think what you have told me is that:
If I Zero my AR15 (16 Inch barrel ) at 25 Yards with Q3131A
It should shoot 6/10ths of an inch LOW at the same 25 Yards;
using Federal 550 Pac .22
Do I have that right??
Exactly. Bore is angled up about 5 minutes above horizontal, causing a .223 to rise up to line of sight by 50 yards, go higher until about 200m, then drop back through LOS and keep dropping. A .22 won't even make it up to LOS at all, but gets closest around 25yds before it drops back away.
JBM online ballistics calculator
Yep. But the 25yd zero isn't all that great for the .223s since it puts the mid-range trajectory so high.