2 people, 1 scope, two POI groups

C

ChrisC

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I was hoping someone could shed some light on this. I am dialing in my rifle for myself and someone else who is going to be using it and noticed that I am getting consistent groups 3 inches high and the other person is right on. Why can a fixed scope have 2 people hitting in two different spots consistently? Is one of the shooters to blame, or is this normal?

Thanks,
Chris
 
I agree it's probably the parallax causing the issue. Most scopes are set at 150 yards if they aren't adjustable. Try shooting it at 150 and see if your groups come together.
Dan
 
It's how you mount the rifle compared to your friend. Move your eye left or right on a stationary gun while sighting a target. notice how much the cross hairs move left and right? Same will happen vertical.
 
Yes one of the shooters is to "blame", and yes this is normal. As others have stated, paralax and rifle cant are most likely to blame
 
Yea, you both shoot a bit different. Could be one of you was canting the rifle a bit.
 
The rifle cannot make decisions for itself. It shoots where it is pointed, period. So what does that leave? The shooter.

Soooo many factors involved. Cheek weld, trigger finger creep/alignment/pressure, sight alignment, sight picture, the list goes on & on.

If, for whatever reason the two of you have to share that one rifle, then I suggest you decide on a fixed sight in, for that rifle, and then each practice with it to learn where they need to aim for any given shot.

Otherwise, you each need your own rifle.
 
Inside a scope is a part called the erector tube. The reticle (the crosshairs) is housed in this tube. 5 inches is a common distance between the shooter's eye and the location of the reticle in the tube. If over that 5 inches, the scope has a verticle cant of just .004" then the bullet will have a 3" impact error. Further, Bryan Litz (ballistician and competition shooter) says that it's been proven that most people can't see a cant angle (in the horizontal) of 3 degrees or less and it would be even more difficult to recognize a cant on the verticle. A cant angle of 1 degree is approx. 0.017" of radial movement (on a 1" circle), so .004" of movement would be about a quarter of a degree or about 1/12th of what your eye could even discern.

Body shape differences and typical errors (that are within the manufacturer's quality specs) in the scope can conspire to cause that 3" error that you are seeing. It's common for two people to create groups in different spots on the target, a common example is the difference between groups shot by a left handed shooter vs. a right handed shooter.
 
A friend and I ran into this exact same issue the other day. We suspected it was because I shoot with glasses, and he did not. Rifle was hitting lower for him than me.

Interesting thoughts here, and something to consider in the future.
 
Definitely very common. Check weld and position are most critical. You can adjust parallax and probably get it closer to same POI. Just curious why doesn't the other person use their own rifle?
 
cahunter805 said:
Definitely very common. Check weld and position are most critical. You can adjust parallax and probably get it closer to same POI. Just curious why doesn't the other person use their own rifle?
Click to expand...

It's their first hunt. I'd hate to have him buy one if he doesn't get into hunting.
 
ChrisC said:
It's their first hunt. I'd hate to have him buy one if he doesn't get into hunting.
Click to expand...

Say you two go out together, he shoots your rifle - which is known to have a different POI when he shoots it as compared to you. Say he blows a leg off, gut shoots, or any one of the other crappy scenarios that lead to wounding loss. Maybe that would lead him to not "get into hunting". And the critters we hunt deserve at least a little respect.
A rifle bought can be sold.
Just a thought......
 
ChrisC said:
It's their first hunt. I'd hate to have him buy one if he doesn't get into hunting.
Click to expand...

If it's their first hunt sight the rifle in for his POI. Let him enjoy the hunt.
Do you only have 1 rifle? If so why not just adjust the scope for you after he has used the rifle to fill his tag?
 
Last edited:
onpoint said:
Say you two go out together, he shoots your rifle - which is known to have a different POI when he shoots it as compared to you. Say he blows a leg off, gut shoots, or any one of the other crappy scenarios that lead to wounding loss. Maybe that would lead him to not "get into hunting". And the critters we hunt deserve at least a little respect.
A rifle bought can be sold.
Just a thought......
Click to expand...

Stupid post. Get off your self-righteous soap box and live in the real world for a day or two.
 
cahunter805 said:
If it's their first hunt sight the rifle in for his POI. Let him enjoy the hunt.
Do you only have 1 rifle? If so why not just adjust the scope for you after he has used the rifle to fill his tag?
Click to expand...

Just one rifle that is suitable for the game we are hunting. I'm always hesitant to adjust a scope without having time to make sure it tracked correctly, so I was just planning to compensate the 3 inches; it's worked well at the range.
 
Depending on what caliber your rifle is and assuming it's 3" high at 100 you should close to a 300 yard zero. Nothing wrong with that. Just remember 200 yards will be about 4" high. Aim at the lower 1/3 of the animal and you should be fine.
Just curious what caliber rifle and what game are you hunting?
 
belly-deep said:
Stupid post. Get off your self-righteous soap box and live in the real world for a day or two.
Click to expand...

What's that mean?
Are you saying that it's OK to go to the field with a rifle that isn't zeroed for you?
Are you saying that having a code of ethics is stupid?

If you are using a firearm for killing an animal then you have no excuse for not having the firearm properly setup for a clean kill. You should be familiar enough with the rifle to make a scope change in the field and know what it's going to do, if you aren't then you haven't practiced enough. If you travel long distance to your hunting area then you should be testing the zero before you start hunting anyways, you never know if the scope got bumped during your trip. It only takes one shot to verify that your scope is still on and if you change shooters then you can make any scope adjustments necessary. Write down the adjustment needed to change from one shooter to the other while you are practicing at the range then take that information with you on the hunt and write down who the rifle is setup for each time you make a change. If you don't write it down I'll guarentee that you will forget.
 
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