Rifle Scopes POI shift when shooting different positions

[Vicko]

So.
Trying to understand my 17HMR rifle and a couple of different loads a little better today soni shot different positions from different ranges.

Noticed that I’m shooting an inch and a half higher when shooting from a barricade type position than when shooting from prone.

Pretty sure it’s not a parallax issue. Is it just slight change of recoil direction/harmonics? Or poor technique?
Or is it common and I should just know to adjust?

 

[Gee Kay]

sight picture perhaps? you might be a tad off to one side (up, down, left or right) behind the scope is my guess. not being square behind the scope, off to a side, will move the poi the opposite direction.

did i word that correctly for the wording police?

 

[j-huskey]

Recoil Management issue (not related to caliber), but stable body mass behind the rifle axis, more mass behind on bench or PRONE pressing forward into a stable rifle,
VS, less mass, less forward weight/stability, and unstable rifle on barricade.

All body movement combined helps create the free movement of the rifle platform.

Secondary, scope shadowing caused by positional change from bench/prone to barricade.

Try, a front bag/solid rest on a bench, after shooting prone, shoot more upright, off elbows on bench, with support hand on the front bag/solid rest and see if you dont shrink the off bench barricade shift by at least half. Or more. Closer to your prone.
If you do, then you will have to determine how to more solidly/rigidly stabilize your free body movement behind the rifle on the barricade.
Best to you,

vr

 

[308pirate]

Is it just slight change of recoil direction/harmonics? Or poor technique?

Definitely the former, with possibly some of the latter as well

Or is it common and I should just know to adjust?

It is common to have different zeroes from different positions. In fact, in some positional shooting sports (NRA highpower rifle), it's common knowledge and verifiable through data book history. If your zero changes from position to position, record that dope and run with it.

 

[smoothy8500]

is it common and I should just know to adjust?

In fact, in some positional shooting sports (NRA highpower rifle), it's common knowledge and verifiable through data book history.

Yes, with both irons and scopes it was noticeable due to changes in cheekweld and eye position behind the scope/sight. Some shooters simply record it in the databook, others try to use the scope "shading" or dark ring to stay center and work on their technique.

 

[Vicko]

Thanks folks

 

[SRPowah]

Yes, with both irons and scopes it was noticeable due to changes in cheekweld and eye position behind the scope/sight. Some shooters simply record it in the databook, others try to use the scope "shading" or dark ring to stay center and work on their technique.

This is the type of cool information that makes the data geek in me want to go test just to see it myself. Can't wait to be back home with my rifles...

 

[smoothy8500]

The noticeable change for me was standing and prone, which definitely affected cheekweld and eye position.

 

[Big_Kumar]

According to my data book, I generally have about a .5-1 MOA horizontal shift between the different positions. 200 yard seated rapid fire seems to be the worst for me with standing and prone being closer together. It is absolutely a body position issue for me.

 

[Vicko]

Reassuring replies.
Sounds like something that I can potentially work on to reduce the effect of, but not be too paranoid about it a long as its consistent.

 

[jpretle]

Is your rifle resting on the barricade in one position and not on the other???
Are you using a sling in the prone position??

 

[Vicko]

Rifle is supported by my hand under the stock palm up in a barricade position.
Not using a sling in either.