Help figuring this out

[BARRYJ]

I'm new to long range shooting with a target scope.  This morning I went chrono my rounds.  10 shot average was 2778.  Shooting a 270 with 130 grain bullets, BC of .460.  My ballistic calculator told me it would drop 13.4 inches or 4.3 moa at 300 yards.  I adjusted 4.25 moa, or 17 clicks on the turret.  It shot 5 1/2 inches high.  Is there something I am not doing right? Only thing I can think of is that when I slipped the turret to adjust after the chrono rounds, I came up 1.25 moa, which is the amount I had to adjust for. It was a little over an inch low at 100 yards for the chrono rounds.

[Powder Finger]

pretty sure it would be 4.3moa / 3 for a scope adjustment of about 1.5

[bushmeat]

If you slipped it 1.25 MOA, that translates to an additional 3.75 inches at 300. So you would have an additional 1.75" inches to account for. Assuming your ammo is grouping consistently, it could be: some wind that's popping your rounds high; not adjusting your parallax; different head or eye position; wrong inputs into your ballistic calculator; or, a combination of these.

[Guy Neill]

Scope adjustments are not always as precise as we may want or expect.

Have you tested the scope by shooting the box, as one test?

As I see it (and I'm not the sharpest tack for some of this) - if each click amounted to 0.35 MOA, it would put you just over 18 inches - just about where you were hitting - assuming I'm getting it near right.

Maybe.

Guy

[BARRYJ]

Thanks for the info.  I'm going back to the range Tuesday to try and figure it out.  Will also do the box test.

[lwink]

Scope height should also be considered, especially on larger objective scopes or anything that sits above your bore a ways. A good ballistics program will have a field for this as the angles it makes you shoot at definitely show up downrange. Can take good measurements of scope and barrel under bell with calipers and divide each by 2 then use feeler gauges or guess with calipers to add the space between scope and barrel. May or may not help but figured I'd throw it your way. 

[BARRYJ]

Think I figured out my problem.  The bolts holding to rings to the base were lose.  So much for having a scope professionally mounted.

[fastshooter03]

When I make a ballistic chart without actual shooting data, I look at the bullet path at the range that I sighted in at for each range I want to figure out for and adjust that amount. 

Say I zeroed at 200 and then wanted to know where to adjust to for 400.  I change the bullet path to be zero at 400 and look how high it is at 200 and adjust accordingly.

But actually shooting at long distance and recording the results is best.

 

 

Nick