POI Shift Mystery

[Skip-in-WV]

I shoot open class FT.

Conditions: same temp, no wind, same elevation, shooting from the same shooting position, same rifle, same pellets, FT target at 55 yards.

Location 1: I aim and shoot dead on to hit and knock down the target.

Location 2: 50 miles apart I have to aim and shoot at the 7 o'clock position to knock down the target.

I'm out of ideas of things to check. Any ideas are welcome.

 

[Yo]

Maybe unnoticeably barely Windier at the other location. Set up staggered wind flags as a tattle tale for you.

 

[Yo]

Bubble level works. Perhaps one location landscaping not perfectly level like a house foundation one side higher than the other to compensate but your butt can't tell.

 

[Guest]

If the wind was calm to slightly breezey I would check into mirage shift. It happened at my most recent match. When the wind would die, or switch the shots were going high. 2/3 scopes were sightron, the other march. I believe the mirage was fooling us into aiming at the wrong spot on the target.

 

[Yo]

OMG I HAVE A MARCH INCOMING!!!

Got plenty Sightrons too!!!

Don't tell me I have to stick with the $200 Aim Sports Alpha6 scopes to keep on shooting straight!!

 

[Guest]

I can't say. Do you use your scopes in conditions that include a 20+deg temp shift?

 

[GLPalinkas]

Skip, are both locations being shot the same day? My RAW and Delta scope combo needs some correction clicks each day. Usually not much.

I would definitely try to Benchrest at each location to eliminate cheek weld/parallax/shooter position errors. I know I find my parallax/cheek weld issue arising just moving from target to target during a Benchrest practice. I have to confirm my cheek weld each and every target. 

Hope you get it worked out buddy. I miss shooting with you at the matches. Maybe in the fall in Ohio. 

Gary

Venice, Fl

 

[Skip-in-WV]

Different days. Same temp in the 70s. No bubble level. Both bench and sitting giving me the same POI at home. No noticeable wind. No mirage seen. I can try both the level and flags.

 

[DonC]

I prefer scope mounted levels. Easiest to calibrate.

 

[bubblerboy64]

Only thing I can tell you is that I see this rather frequently. I have a suspicion it’s some times conditions but also I suspect the internal conditions of the barrel.

i used to shoot a lot of small bore (22 rim fire) silhouette. I always checked the gun on paper at at least one distance. Rarely did I not have to adjust the scope some. Frequently what would happen is my first shots would be off maybe as much as an inch . I’d adjust and continue to shoot adjusting as I would go and some times the group would walk back to its original position. Air gun? I find the only thing that stays the same is things are always changing. I know for a fact that a very small change in wind can have a large affect beyond 25 yards. Change pellets? WOW. so no question that there are variables at work. Lighting. Gun hold. WIND and vertical position of the target up or down.
I’ve got a 223 that’s got me puzzled. Shoots great accurate as anything I have owned but the POI will change. I haven’t figured it out. Top notch scope nothing seems loose but I have to sight it in each time I shoot it or I can’t trust it. Only thing I do differently is I do carry the gun around in the car because I use it to hunt ground hogs with. I don’t think the gun gets bumped but if I miss a GH I know to head to the range and sight it in. Some times it’s off an inch or more at 100. Adjust the scope and it will put them under a dime at 100 and under a quarter at 200.
Somethings up but I don’t know what. From my experience when scopes fail the groups open. Anyone know differently. ? It’s a leupold Mark 4 scope. New 

 

[Skip-in-WV]

This phenomena has occurred at least on 4 separated days a week apart.

 

[Bob-in-WV]

You are still shooting pretty good Skip.

 

[Yo]

Different days. Same temp in the 70s. No bubble level. Both bench and sitting giving me the same POI at home. No noticeable wind. No mirage seen. I can try both the level and flags.

SO! You actually shooting FT without a bubble level?

 

[allenbowles]

wind-wind and i mean any wind...

 

[db45]

I have had this happen because of the hard gun cases I use. It appears to put pressure on scope / mounts. When shooting day to day from same location its consistent. After casing the rifle in question, even to store in closet I can have a P O I change. db

 

[AirNGasman]

Different days.

 

[KPinWI]

Are the two places significantly different in elevation with respect to sea level?

 

[Skip-in-WV]

Not more than a couple hundred feet form the map

 

[GLPalinkas]

Different days. Same temp in the 70s. No bubble level. Both bench and sitting giving me the same POI at home. No noticeable wind. No mirage seen. I can try both the level and flags.

SO! You actually shooting FT without a bubble level?

Hey Yo, stop giving him advise. I shoot Open PCP against him and he is good enough for me. LOL 

Seriously though, you are correct. I never noticed he didn’t use a level. He shoots very well but lately has been having trouble. May be the cause.

Gary

Venice, FL

 

[Skip-in-WV]

The rail mounted level didn't seem to make much difference. Easy enough to put one back on.