C-More zeroed at 17 yards shooting low why?

[Jaxshooter]

I zeroed my 9mm open gun at 17 yards from a rest. Shot 5 rounds with all bullet holes touching, perfectly centered. I shot the gun from 17 yards offhand and all shots were approximately 1 1/2 - 2" below where dot is on target still a tight centered group , why? Before anyone asks all mounting screws and scope screws are tight. The gun has an arched mainspring housing so if anything it should be a little higher offhand.

Tell me what you think the problem is.

Thanks

Edited June 21, 2009 by Jaxshooter

[uscbigdawg]

Bad gun presentation or trigger control.

Rich

[G-ManBart]

Many time Open guns don't act the same from a rest as they do shooting offhand. The recoil and flip part of the equation has been changed by having it on a rest. If I recall correctly C-More's aren't completely parallax free so if your head was in a different position off the bench that would change the POI a little as well. If it was a trigger control problem the rounds wouldn't all be in a tight group and almost certainly would have moved left or right. R,

[Jaxshooter]

Thanks G-Man. I am sure off the rest my head was down more than when I shoot. I shoot with my head very upright. The groups were tight up and down as well as left to right off of the rest and offhand. The offhand groups were just low but still centered. I adjusted the C-More shooting offhand until I got the shots up to my sight line.

Edited June 21, 2009 by Jaxshooter

[shred]

Take a look at your glasses. Carefully check to see if they distort at the top of the lens. I had a set years ago that would do that.

[PistolPete]

Not sure if this is your issue but:

An open gun will have a different impact area because the dot is much higher above the actual bore of the gun. This, combined with the arc of the bullet will have the gun shooting low at closer ranges, high at further ranges, and then again back to where it is zeroed at even further distances. This is prob. what you are experiencing. After you shot the group at the further target and then the closer one did you bring the target back to the further one to see if it was hitting in the correct location?

Pete

[G-ManBart]

Not sure if this is your issue but:

An open gun will have a different impact area because the dot is much higher above the actual bore of the gun. This, combined with the arc of the bullet will have the gun shooting low at closer ranges, high at further ranges, and then again back to where it is zeroed at even further distances. This is prob. what you are experiencing. After you shot the group at the further target and then the closer one did you bring the target back to the further one to see if it was hitting in the correct location?

Pete

He said both off the bench and offhand were shot at the same distance....17yds.

[Jaxshooter]

I sighted in at 17 yards from the rest and then shot from 17 yards offhand. From the offhand position the shots were impacting low as compared to the shots fired from the rest. Both groups were tight and centered just lower than from the rest.

[G-ManBart]

I sighted in at 17 yards from the rest and then shot from 17 yards offhand. From the offhand position the shots were impacting low as compared to the shots fired from the rest. Both groups were tight and centered just lower than from the rest.

Here's a quick read on what I was talking about. Dave has a nice description that's relatively short and easy to follow:

http://www.brianenos.com/forums/index.php?...st&p=922621

[blkbrd]

Pistols and rifles will have different impact "sometimes large" points depending on how its rested or held.

My Open gun when sighted in for 25 yards off a rest hits 3" low offhand, even though groups don't enlarge much.

My comped AR's shoot 3-5" lower offhand as rested, and my High Power rifle shoots 3-4" high.

Depends on how the recoil vs. unlocking vs. hold change.

The only way to do it is sight in the way you plan on shooting the gun and reserve the bags for load testing groups.

[38supPat]

Get someone else, preferably someone you know who is a good shooter and try the same thing, 17m group off the bench, then 17m group offhand, see if the results are the same...

[Txkid]

My 2 cents, you can try this at home,

Make sure you have an empty chamber and remove the mag, turn on the red dot and place the magwell flat on to a table/counter top anything that is flat and sturdy.

Point your red dot to an object. With out moving the gun look at the red dot move away from the object when you move your eye left to right top to bottom of the lens.

I was surprised how the dot moves around especially with the elevation.

You are possibly not aiming from the same position of the lens when you shot free hand?

Thomas

[Gregory_k]

Not sure if this is your issue but:

An open gun will have a different impact area because the dot is much higher above the actual bore of the gun. This, combined with the arc of the bullet will have the gun shooting low at closer ranges, high at further ranges, and then again back to where it is zeroed at even further distances. This is prob. what you are experiencing. After you shot the group at the further target and then the closer one did you bring the target back to the further one to see if it was hitting in the correct location?

Pete

2 mounts fix that (so called) "problem" and make the gun more "natural" to shoot.

[HSMITH]

I get mine sighted in reasonably close off a rest and dial them in offhand, I see a couple inches difference at 25 yards. I will see a couple inches at 50 with a Limited gun too. Not a big deal or even anything to be concerned about. Sight it in the way you are going to shoot it and be done.