Are .223 Rifles With Red Dots That Have a 50M Zero also Zero'd @ 200M?
- Thread starter Mr. Spectacular
- Start date
based on the difference between the line of the bore and the line through the middle of the sight (likely about 2 to 2.5 inches with the setup they're talking about, the bullet travels up through it's arc and passes through the line of sight at 50 yards (still going up), then levels out around 100 or 125 yards where it will be an inch or so high, then begins to fall as it again passes through the line of sight (zero) at 200 yards. Think about a trajectory (arc = flight of bullet) with a horizontal line through it (line of sight).
Hope this helps, if not I will do an illustration later on.
Cheers,
Brobee
Hope this helps, if not I will do an illustration later on.
Cheers,
Brobee
Ar180shooter
CGN Ultra frequent flyer
- Location
- Ottawa, ON
Technically, the bullet never rises relative to the bore axis. It starts accelerating toward earth as soon as it leaves the bore, and never gains 'height' relative to the original bore axis.
The 'rise' and 'fall' are all relative to the angle between sight height and bore height/where the optical axis is for the sight (dependent upon zero). Up close, the angle from sight to bullet path is so sharp the sight-target axis is "below" the path of bullet impact. They cross at one point close-in, and again at a point farther out when the sight-target axis is then "above" the path of impact.
So it's sort of semantics... but the bullet doesn't arc up and down like a football relative to the bore axis - it's "falling" from the time it comes out, and it's just geometry that gives rise to the plots that show positive height relative to the sight axis.
-M
Bolivar
CGN Ultra frequent flyer
Yes, but the bullet does rise relative to a flat plane of ground (say) or the line for sight through the sighting system to the target. The bore axis is pointed upward on the shot to targets at any distance, unless you press the muzzle to the target
Of course as range gets very short, the required angle of the muzzle to achieve a centered hit is negligible. Heck, for shooting 1000 yards the muzzle angle from horizontal is essentially negligible.
No I have not measured it, never really thought to.
Ar180shooter
CGN Ultra frequent flyer
- Location
- Ottawa, ON
Yes, but the bullet does rise relative to a flat plane of ground (say) or the line for sight through the sighting system to the target. The bore axis is pointed upward on the shot to targets at any distance, unless you press the muzzle to the target
Of course as range gets very short, the required angle of the muzzle to achieve a centered hit is negligible. Heck, for shooting 1000 yards the muzzle angle from horizontal is essentially negligible.
No I have not measured it, never really thought to.
Yah, 1 degree = 60 MOA = 600 inches of drop @1000 yards. Kind of helps put it in perspective, no?
JBM is your friend when you have questions like this:
http://www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi
Be sure to input the correct scope height as well, this can have a significant effect on the results.
http://www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi
Be sure to input the correct scope height as well, this can have a significant effect on the results.
ghostntheshell
CGN frequent flyer
- Location
- GTA ONTARIO
This.
How high is the EOTech dot above an AR bore?
For ordinary bolters with a scope, the usual rule of thumb is 1.5", and for most hunting rounds the thinking is that the bullet first crosses the line of sight at ~25 yards then falls back at ~200 yards.
Given that this is the black rifle forum, I choose to leave the bolt guns with the scope out of the equation.
Standard sight height on an AR is 2.5" with the carry handle if I'm not mistaken. EOtech, not sure....aimpoints can vary depending on the mount.
