MOA BASE
- Thread starter sully7mm
- Start date
Fred Bohl
Gold $$ Contributor
sully7mm
The following is for 6BR, 107gr SMK, 280ofps MV, scope CTR line 2.7in over bore CTR line:
yds = MOA
100 = 4.79
200 = 5.90
300 = 8.11
400 = 10.78
500 = 13.84
600 = 17.27
700 = 21.11
800 = 25.40
900 = 30.22
1000 = 35.65
Mount tilt to keep scope elevation adjustment centered
,includes correction for height of scope over bore)
The following is for 6BR, 107gr SMK, 280ofps MV, scope CTR line 2.7in over bore CTR line:
yds = MOA
100 = 4.79
200 = 5.90
300 = 8.11
400 = 10.78
500 = 13.84
600 = 17.27
700 = 21.11
800 = 25.40
900 = 30.22
1000 = 35.65
Mount tilt to keep scope elevation adjustment centered
,includes correction for height of scope over bore)
Fred Bohl
Gold $$ Contributor
NateHaler,
The primary need is dictated by the ballistics of your load and conditions such as air density,temperature, humidity and altitude). The example data above is for the specified round performance and at "standard conditions".
The scope needs to be considered for: its available adjustment travel; adjustment "click" value deviation away from center; and distortion/aberration/focus shift with off axis settings.
To cover the full F-Class,300 to 1000 yards) gamut and assume a need to accommodate various conditions, one would probably be safe selecting the commonly available 20 MOA rail tilt and thus limit the elevation offset to about -14 to +18 MOA for this example. If your shooting was limited to a narrower spread of ranges then the goal would be to have a rail made with a tilt in the middle of the range to limit the elevation offsets required. Say you were competing at the Palma ranges,800, 900 & 1000 yards) then you would make the tilt 30 MOA and limit the elevation offsets to about -7 to +7 MOA.
The primary need is dictated by the ballistics of your load and conditions such as air density,temperature, humidity and altitude). The example data above is for the specified round performance and at "standard conditions".
The scope needs to be considered for: its available adjustment travel; adjustment "click" value deviation away from center; and distortion/aberration/focus shift with off axis settings.
To cover the full F-Class,300 to 1000 yards) gamut and assume a need to accommodate various conditions, one would probably be safe selecting the commonly available 20 MOA rail tilt and thus limit the elevation offset to about -14 to +18 MOA for this example. If your shooting was limited to a narrower spread of ranges then the goal would be to have a rail made with a tilt in the middle of the range to limit the elevation offsets required. Say you were competing at the Palma ranges,800, 900 & 1000 yards) then you would make the tilt 30 MOA and limit the elevation offsets to about -7 to +7 MOA.
sully
If you are only shooting 600 yards - don't worry about it. 10 MOA comeup will accomodate almost any cartridge you may want to shoot. Most any medium to high quality scope will handle that with ease.
For longer distances,1000 yards) you will need to chronograph your loads, run a ballistic table, measure the distance between scope bases - and some simple math will give you the answer. For a quick and dirty - figure .006" of shim per 1" distance between scope bases.
Don't forget, if you center at the longest distance you may not be able to get on paper at 100 yards. There's no free lunch. Do what Fred says and go for a practical compromise.
JMHO
Ray
If you are only shooting 600 yards - don't worry about it. 10 MOA comeup will accomodate almost any cartridge you may want to shoot. Most any medium to high quality scope will handle that with ease.
For longer distances,1000 yards) you will need to chronograph your loads, run a ballistic table, measure the distance between scope bases - and some simple math will give you the answer. For a quick and dirty - figure .006" of shim per 1" distance between scope bases.
Don't forget, if you center at the longest distance you may not be able to get on paper at 100 yards. There's no free lunch. Do what Fred says and go for a practical compromise.
JMHO
Ray
Fred Bohl
Gold $$ Contributor
Sully & Ray
You may find these links to simple calculators helpful:
Scope Mounting Tilt Click Here
Sight Correction Click Here
These can help pick the nearest offset insert for Burris Signature Rings with less trial and error. Used with an optical collimator,optical boresighter) you can measure the misalignment of the scope in the 0-0 inserts then calculate both the windage and elevation correction needed then pick the nearest offset insert set for windage,set with split vertical) in the front ring and for elevation,set with split horizontal) in the rear ring.
You may find these links to simple calculators helpful:
Scope Mounting Tilt Click Here
Sight Correction Click Here
These can help pick the nearest offset insert for Burris Signature Rings with less trial and error. Used with an optical collimator,optical boresighter) you can measure the misalignment of the scope in the 0-0 inserts then calculate both the windage and elevation correction needed then pick the nearest offset insert set for windage,set with split vertical) in the front ring and for elevation,set with split horizontal) in the rear ring.
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