Trouble zeroing a scope

[BoomieMCT]

I have a Ruger .44 carbine I've been noodling around with. I got it with a Nikon Buckmasters 3-9 scope. It worked fine but I wanted something lighter so I put my Leupold VX-1 shotgun scope on it. I then got it on paper at 50 feet to zero at 50 yards (max of the indoor range I shoot at). If I was hitting the bull at 50 feet then it was about 4" left and 2" high at 50 yards. I don't think the scope is canted as the older scope worked fine. Is there anything else that could cause this?

 

[PetahW]

I would zero it @ 50yds, an inch high and dead nuts on for windage - then check it @ about 100yds, even if the 100yd check had to take place in hunting terrirory.

IMHO, 50' is too close, since any minute error at that short distance is multiplied four-fold (4x) @ 50yds, and at least eight-fold (8x) @ 100yds - not to mention that at 50' parallax often raises it's ugly head (false zero).


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[BoomieMCT]

Hmmm. I was hoping that using a shotgun scope might remove or reduce parallax errors at that close range. Oh wells.

 

[jmr40]

Parallax is not your problem. You just THINK it is zerod at 50'. It is actually off a tiny bit and you don't notice it until you shoot it at longer ranges. Tiny errors just don't show up at close ranges. Zero at 50-100 yards then go back to closer ranges and make a note of where you are hitting.

The scope is 1.5" higher than the barrel. The barrel is pointed up in relation to the scope and that is why you are high at 50 yards and appear to be zeroed at 50'. A 50 yard zero will leave you 1.5" or so low at 50' because the bullet has not had time to rise up to your line of sight.

 

[Sweet Shooter]

I'd like to disagree. Zeroing at 50 rules out lots of variables that you could spend a lot of time and money fighting at ranges of even as little as 100.

Most calibers... zero dead on @50 or just under, and you'll be on again at 100 or just a little after. With real screamers (22 250, 270 etc) if you're on @50 you'll be on at 150+. Make sure that your crosshairs are perpendicular over the bore (square just isn't good enough) and zero for 50. Further ranges will see the trajectory track in line with the crosshairs... learn you trajectory. You can always check then at 100, 200 yards and you'll be amazed.

If you can shoot one ragged hole @50 you can put the internet to rest and sleep easy that you are on at "infinity" at least with windage... again learn the trajectory for your chosen cartridge.
-SS-

 

[coyota1]

A bullet doesn't travel in a straight line, but more like a bowling ball, or a curve ball. This could be one of the variables you are dealing with.

 

[1Hobie]

A bullet travels in a parabolic arc. The further out you shoot the higher the arc. Gravity pulls straight down on the projectile so you have to elevate to compensate for this. However, if you shoot either up or down hill, you will over-shoot because of the lessened effect of gravity in the trajectory of the round.

http://www.millettsights.com/downloads/ShootingUphillAndDownhill.pdf

There are studies done on a wide variety of things that affect projectile performance:

https://en.wikipedia.org/wiki/External_ballistics

Okay, I was bored but there is some good reading, although lengthy, about all things ballistic.

Regards,

Hobie

 

[Mobuck]

I agree that you probably had some slight scope setting error at the 50' range that was multiplied 3X at the 50 yard range. Getting on paper at short range is acceptable but can't be guaranteed to be exactly right at longer range-just close.