cboom
Well-Known Member
Probably a dumb question? All the apps ask what the scope height is. So if you have a rail with moa built in (20 in my case) Do you measure from the front of the scope, middle, or what?
Scope height?
- Thread starter cboom
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cahunter805
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- Jun 18, 2010
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I use this method. Seems to work well.
If your rail is about 7 inches long, 20 minutes of angle is only about 0.04 inches difference from one end to the other, so I doubt it matters much. I'd just measure from whichever point on the rifle affords you the most accurate reading.
Hugnot
Well-Known Member
I measure my scope heights from center of scope exit pupil to center of bore.
cboom
Well-Known Member
Thank you. I know it isn't much difference in that 7 inches. Was wondering if that small amount made much of a difference at range? Just got gun built, in the next couple weeks I will get it figured out putting dopes in the apps (compared to speeds the crony reads) and see what I got.
cboom
Well-Known Member
That's probably the best way to get set up?
Like Sam said in the video it doesn't have to be perfect but it definitely does make a difference, especially the farther out you go. It's also easy to measure as demonstrated. Inside of 500-750, unless your way off on your measurement, it won't really matter. Might cause you to be 0.1mils or so off. Start pushing it out past 1000 and it becomes 0.5+mils.
JungleShooter
Well-Known Member
I'm sure for closer ranges absolute precision is not a big factor. But when minute precision counts for way out there shots, well...
So, you'll excuse me to bring this up:
Despite the "ridiculously" short ranges of airguns the demands on their precision are huge:
▪one inch and two inch kill zones
▪elevation adjustments of over 10 mil or more to reach mere 150 yards
▪ranging error of 2 yards can move your shot already outside the kill zone (@ 70y)
▪a light 5mph wind moves the shot outside the kill zone — at a range of only 45y
All that to say, the most precise method I know of is to measure the distance from point of aim to point of impact pretty much at the barrel (if your scope only parallaxes down to 100y, that method won't work, sorry).
The instructions are fairly straight forward, right here:
airgunaccuracy.wordpress.com
Matthias
So, you'll excuse me to bring this up:
Despite the "ridiculously" short ranges of airguns the demands on their precision are huge:
▪one inch and two inch kill zones
▪elevation adjustments of over 10 mil or more to reach mere 150 yards
▪ranging error of 2 yards can move your shot already outside the kill zone (@ 70y)
▪a light 5mph wind moves the shot outside the kill zone — at a range of only 45y
All that to say, the most precise method I know of is to measure the distance from point of aim to point of impact pretty much at the barrel (if your scope only parallaxes down to 100y, that method won't work, sorry).
The instructions are fairly straight forward, right here:
Chairgun and “Scope Height”
I hear a lot of people complaining about the ballistic software Chairgun not being in line with their real world results. But in my field target rifle and scope combo’s it has improved to bei…
airgunaccuracy.wordpress.com
Matthias
Yes but how much out on your measurement do you have to be to change all your setting. I had my riflezeroed for 300yds but was out on my sight height. At 750yds I was way high. I knew my velocity and G7 BC. Can any one answer this for me with out derailing this thread.
I measure from center of bore to center of windage adjustment knob.
azarcher10x
Well-Known Member
- Joined
- Nov 12, 2012
- Messages
- 241
If you've put in all the basic measurements, and have good sight settings for say 100 and 1000 yards, you can play with the scope height measurement by shooting it a close distance of 10 yards. If you're high or low at that distance, you can play with the scope measurement. Highly doubtful it will that much difference in your shooting, but if you have that much ammo to shoot up, have fun!
Almost all scopes are mounted at two inches over bore. The old scopes with small tubes could be at one inch. At an informal benchrest league I measured six to ten rifles and all were within a fraction of two inches.
