Newb question (long post)

[adam p]

About a year ago I had my 243 win. rebarrled by Shilen. It is a Rem 700 BDL. I had Shilen put a 26" 7HV contour barrel with a short throat ( 65 grn Shilen BR bullets) on it along with a 1.5# trigger. I put the action in a McMillan A3 stock. I feel like this set-up is capable of shooting long range as long as it isn't to windy. I have already read on this forum to not completely trust ballistics programs, so I plan on taking the time and shooting and recording the zero at various ranges.The main thing I am having trouble with is figuring out how much to move the scope ( Nikon 6-18 with target turrets) at various ranges. I know at 100 yards it is 1/8 minute, but what about out at 4,5,600 yards and so on. I have been trying to figure this out and it is racking my brain. I found this forum and it seems like ya'll know what you are talking about so I figured I would ask before my head exploded. Also how far do ya'll think this gun is capable of shooting. Thanks in advance

 

[royinidaho]

Welcome aboard adam b,

You think that's tuff wait till you start coverting moa to mils and and talking come-ups /ubbthreads/images/graemlins/crazy.gif

I have a hard time keeping my mind wrapped around this stuff also.

Someone is probably providing a much better answer as I'm typing.

1/8 MOA @ 100 yds is just about 1/8 inch. The difference in neligible all the better my guns shoot. /ubbthreads/images/graemlins/grin.gif

1 MOA @ 100 = 1"
1 MOA @ 200 = 2"
1 MOA @ 1000 = 10"

When you do your shooting as I did a couple of weeks ago my points of impact were:

200 yds = 4.25" or about 2.1 MOA
311 yds = 0.25" (0.25/3.11) = close enough
438 yds = -13" (-13/4.38)= 2.9 MOA
540 yds = -32" (32/5.40) = 5.9 MOA

If someone finds this is off base, let me know QUICK /ubbthreads/images/graemlins/confused.gif

HTH at least a little bit. I did a search on "come ups" over the last 2 years and got 43 hits. Might be something there.

 

[Varmint Hunter]

Your 1/8 minute scope click (or adjustment) represents:

1/8 of an inch @ 100yds
2/8 of an inch @ 200yds
3/8 of an inch @ 300yds.........
........and so on

If you wanted to move the bullet impact 2" @ 100yds then it would take 16 clicks on your scope.

However, the same 16 clicks would move the impact twice as far (4") @ 200 yds and five times as far (10") @ 500yds.

 

[Marine sniper]

1 minute of angle is 1.047 inches for every 100 yards. On your scope 1 click (1/4 minute) on a scope calibrated in minutes is (very close to) .262 inches per 100 yards.

 

[adam p]

My main question was how much a click would move the point of impact at further ranges. I think the post by Roy has got me moving in the right direction I just need to go out and field varify my ballistics chart to get this thing whipped.

 

[Dave King]

You state that your scope is 1/8 "clicks".

If you zero your rifle (rifle,ammo,scope setup) at 100 yards you should print a group zero inches high, zero inches low and with correct windage.


100 yards::

Now, if you "click" your scope up 8 click and shoot again at 100 yards you should be approx. 1" high (point of impact 1" above point of aim).


200 yards::

If you have your scope set to your 100 yard zero (point of aim = point of impact at 100 yards) and shoot a group at 200 yards your group will be below your point of aim by several inches. Walk to the 200 yard target (imaginary so we can do this quickly) and measure the distance the group is below the point of aim. We'll call it 2.25 inches low....

Your question is how much do you need to adjsut the scope to make the 200 yard group match the point of aim at 200 yards.

The imaginary group we just shot (low recoil group) is 2.25 inches low. To move that group to match point of aim we need to adjust the elevation an amount equal to 2.25" at 200 yards... The value you need to accomplish this is determined by dividing the distance to move the point of impact by the distance in hundreds of yards. 2.25" / 2 (2 hundred yards) = 1.125 (MOA in reality) You need to adjust your scope 9 "clicks" up to make the 1.125 MOA. This adjustment will make 2.25" at 200 yards.

400 yards:::

We'll shoot another imaginary group....

High speed walk and measure and it's 20" low using the 100 yard zero.

To calculate the adjustment needed, 20" / 4 (400 yards) = 5 MOA (not exact but close enough for us) of correction required. You have a 1/8 MOA scope so we need to come-up 5 MOA or 5 X 8 = 40 "clicks" for a 400 yard zero.