-
Legacy Member
Rear sight graduations in moa?
My search went with out any hits.
Anyone know the approximate or mathematical change in MOA between the different settings
100-200-300-400 etc . ?
I have a table I found for the 1903a3 and it's been extremely helpful in matches.
Information
|
Warning: This is a relatively older thread This discussion is older than 360 days. Some information contained in it may no longer be current. |
|
-
-
10-18-2015 04:53 PM
# ADS
Friends and Sponsors
-
Advisory Panel
You did not specify to which rifle the question refers, making it at first glance a bit like "how long is a piece of string?"
But it doesn't really matter... since it seems to me that the change in elevation angle (MOA) between various sighting distances is going to depend on the external ballistics of the ammo used - and nothing else!
For instance, I have a set of tables for BP muzzle velocities from the Arquebusiers de France website, and have found it to be quite accurate in practice. Good enough to get straight on target going from 300 to 1000 yards - the largest step I have ever made. But you need to know the muzzle velocity of the bullet and its ballistic coefficient. What does not matter a hoot is whether the bullet is flying out of a Sharps, Remington, Springfield, or anything else - it's all a question of external ballistics.
The same will apply to smokeless-powder ammo, just that the steps in MOA will be smaller, because of the higher muzzle velocities.
To a first approximation, if your Swiss rifle is firing bullets with the same muzzle velocity and BC as the 1903A3, then the range steps IN MOA, NOT INCHES or MM will be pretty much the same. The elevation height change of the slider in inches or mm will, of course, depend on the sight radius, so on a G11 the elevation height change will be larger than on a K11, but the elevation angle change will be the same, as both used GP11 ammo.
But don't expect to simply "dial in" a change in MOA and go from a 10x at 100 yards to a 10x at 1000. The larger the range change, the more that subtle factors like wind, temperature etc. will play a role in fine tuning the setting. There are ballistic programs for this stuff, but for practical use the tables should be good enough to put you on target, even in the black, when going from one target distance to another.
Now although no-one can give you an exact elevation height scaling for an unspecified rifle, you can measure it easily enough yourself. Simply use the depth-gauge function on a slide gauge a.k.a. vernier calipers to measure the elevation height steps, measure the sight radius, and calculate the angle A from the relationship Tan A = elevation height step divided by the sight radius.
Last edited by Patrick Chadwick; 10-18-2015 at 05:42 PM.
-
-