First and Second plane reticles
I have a second plane scope reticle on all scopes; the reticle doesn’t change in size as you increase magnification.
What I didn’t realize is if you sight in at 100 yards with 9 power, then shoot at 200 yards with 12 power, the point of impact may not be the same had you shot 200 yards at 9 power. Now I may have this all wrong, so I’m open to corrections and suggestions.
Example: I have a Nikon M-308 800BDC scope on my 6.5 Creedmoor. It has circles and hash marks on the entire lower vertical reticle for holdover at various ranges. I went to the Nikon Ballistic website and entered data for a Sierra 140gr SPBT at 2610 fps.
If I sight in at 100 yards using 9 power, the first circle(hash mark)should put the bullet at 209 yards, which means that Point Of Impact should be high. If I use 12 power to shoot that first circle, the POI is 186 yds so the POI should be low.
Now if I sight in at 200 yards at 9 power, the first circle should put the bullet at 282 yards; if I shoot at 12 power, the reported POI is 262 yards.
In each case the point of impact is lower as you increase the magnification.
If I look at trajectory tables, I will be able to discern bullet drop at each yardage based on velocity. But it does not tell me what scope magnification will match that trajectory.
Nikon instructions relate that their ballistic tables and scope hash marks are based on maximum magnification. So it seems if you are going to use the scope hash marks for bullet drop at various ranges, you should sight in at max and shoot at max at all ranges. What’s the point of having a variable magnification?
With a second focal plane variable scope, what’s the best way to sight in and use hash marks for various ranges?
I have a second plane scope reticle on all scopes; the reticle doesn’t change in size as you increase magnification.
What I didn’t realize is if you sight in at 100 yards with 9 power, then shoot at 200 yards with 12 power, the point of impact may not be the same had you shot 200 yards at 9 power. Now I may have this all wrong, so I’m open to corrections and suggestions.
Example: I have a Nikon M-308 800BDC scope on my 6.5 Creedmoor. It has circles and hash marks on the entire lower vertical reticle for holdover at various ranges. I went to the Nikon Ballistic website and entered data for a Sierra 140gr SPBT at 2610 fps.
If I sight in at 100 yards using 9 power, the first circle(hash mark)should put the bullet at 209 yards, which means that Point Of Impact should be high. If I use 12 power to shoot that first circle, the POI is 186 yds so the POI should be low.
Now if I sight in at 200 yards at 9 power, the first circle should put the bullet at 282 yards; if I shoot at 12 power, the reported POI is 262 yards.
In each case the point of impact is lower as you increase the magnification.
If I look at trajectory tables, I will be able to discern bullet drop at each yardage based on velocity. But it does not tell me what scope magnification will match that trajectory.
Nikon instructions relate that their ballistic tables and scope hash marks are based on maximum magnification. So it seems if you are going to use the scope hash marks for bullet drop at various ranges, you should sight in at max and shoot at max at all ranges. What’s the point of having a variable magnification?
With a second focal plane variable scope, what’s the best way to sight in and use hash marks for various ranges?