Question about a 20MOA mount

[shooterrex]

Ok I sighted in at 50yds 0.4" high. Balastic program says that's what will make it dead on at 200yds. So why is it shooting 4" high at 275 yds? Am I missing something.

This is my 6.5 Creedmoor.

I only have targets at 50 ,89, and 275 yds this time of year with crops in The field.

Shooting Hornady American Gunner 140's

[Albroswift]

Does the ballistic program 

A: have a scope over bore dimension setting? Maybe you are off a little there. 

B: what does the table show you should have at 275 yards?

I don't like to use a 50 yard number to set up a ballistic table, to much chance for inaccuracy. Things like sight over bore dimension are a lot more critical the closer you get. 

 

[shooterrex]

Yes it has sightline over bore.

Think I read the table wrong.

Supposed to be 0.5" low at 50yds not high.

 

Edited July 14, 2022 by shooterrex

[98Z5V]

8 hours ago, shooterrex said:

Supposed to be 0.5" low at 50yds not high.

That will make a tremendous difference in the rest of the dope chart, brother. Re-zero that thing, and get back after it, and confirm your chart.  After that, you'll have the confidence to trust it, and verify it at longer distances.  "Ballistic Truing."

[98Z5V]

19 hours ago, shooterrex said:

Balastic program says that's what will make it dead on at 200yds.

Question, here...   Why are you going for a 200-yard zero?  That complicates things later on, for shooting longer distances - and that cartridge will do longer distances, easily.

Why not set the ballistic chart up for a 100-yard zero, alleviate some of those issues, and use the chart to zero at the distance you have, for 100?

I have 30 MOA in the base on my .300 WIn Mag.  With the Nikon scope I have, I can't zero shorter than 500 yards.  It's dead-nuts at 500 yards, too.  I have to use hold-unders to shoot shorter.  It's 16.9 mils of dial for a mile, though.  I'd zero it shorter, if I could zero it shorter.  My 500-yard zero complicates things for me.  I don't have the internal travel in the scope, with the 30 MOA base, to do any better than that, so I live with it/deal with it.