Shooting position affect on impact (HMR)

[PPP]

Now that the crops are away I'm finding myself using sticks more on the rabbits.  I haven't used my HMR for ages due to not holding zero and months/years of fault finding due to the various permutations, but its now been replaced by Hawke as faulty and i have zero it at 100M prone with tragedy hole groups, so its back!

It appears that the POI off sticks is about 8cm higher than prone, is this to be expected or am i doing something wrong?  I'd rather not have to rezero and my turrets are under caps so its tricker and less obvious to 'dial in'

Thanks!

[Ultrastu]

Prone will often produce a different poi to the other positions .

Sitting, kneeling ,standing ,bench dont usually give a different poi .but prone does .

Its due to 

A  -  how the butt sits (or doesnt ) in the shoulder pocket .and 

B-   how the head is angled down to the scope and the tendancy to look through the top half of your eye in relation to the reticule and eye bell lens.

The above is the reason some shooters .will either always shoot prone .or not at all .2 different zeros required .

[PPP]

1 minute ago, Ultrastu said:

Prone will often produce a different poi to the other positions .

Sitting, kneeling ,standing ,bench dont usually give a different poi .but prone does .

Its due to 

A  -  how the butt sits (or doesnt ) in the shoulder pocket .and 

B-   how the head is angled down to the scope and the tendancy to look through the top half of your eye in relation to the reticule and eye bell lens.

Superb, thanks!  Its rare that I shoot rabbits (or anything) prone, it was just to set the scope up.. Much appreciated!

[Scully]

3 minutes ago, Ultrastu said:

Prone will often produce a different poi to the other positions .

Sitting, kneeling ,standing ,bench dont usually give a different poi .but prone does .

Its due to 

A  -  how the butt sits (or doesnt ) in the shoulder pocket .and 

B-   how the head is angled down to the scope and the tendancy to look through the top half of your eye in relation to the reticule and eye bell lens.

The above is the reason some shooters .will either always shoot prone .or not at all .2 different zeros required .

Really? I have zeroed both rf and cf  prone off bipods and then gone on to shoot off sticks, fence posts, gates, Landrover roofs and bonnets, and freehand, and never noticed any difference which made a difference to any quarry I’ve shot! 
Head shot rabbits with my .22 prone have still been headshot rabbits from a vehicle and freehand.

 

[Ultrastu]

To be fair .

It also has a lot to do with the quality of your scope - parrelax error and exit pupil size .

And last but not least .the shooters ability to achieve consistent eye position behind the scope .

 

And yes ,   really .

 

I havent gone into the possible difference in how a bipod fixed at say the end of the fore end can add a different pressure into the barrel than say sticks supporting the stock further back nearer the trigger .

If the barrel isn't free floating from the stock .or the fore end effects the breech block when different pressures are applied  .

[Walker570]

19 minutes ago, Scully said:

Really? I have zeroed both rf and cf  prone off bipods and then gone on to shoot off sticks, fence posts, gates, Landrover roofs and bonnets, and freehand, and never noticed any difference which made a difference to any quarry I’ve shot! 
Head shot rabbits with my .22 prone have still been headshot rabbits from a vehicle and freehand.

 

100%   Set zero in the most comfortable unmoving place possible, off a table on sand bags is ideal.   After that if you miss it is the nut behind the trigger.

On our sniper training days we where allowed 5 shots off of our bypods to check our zero which rarely needed adjustment from the month before. From that point on we where expected to put that bullet on target from every position possible the extreme being the 400 yrd run down with 2 shots fired at every 50 yard point from whatever obstacle was provided, post, fox hole, wall, grass knoll and then at 100yrds fire five shots standing all at 2 second exposures.  This was shooting 125g Winchester 308Win cartridges which was the issue round for urban use. 

[London Best]

Stu is 100% right. But only for a springer air rifle.

[Scully]

43 minutes ago, Ultrastu said:

To be fair .

It also has a lot to do with the quality of your scope - parrelax error and exit pupil size .

And last but not least .the shooters ability to achieve consistent eye position behind the scope .

 

And yes ,   really .

 

I havent gone into the possible difference in how a bipod fixed at say the end of the fore end can add a different pressure into the barrel than say sticks supporting the stock further back nearer the trigger .

If the barrel isn't free floating from the stock .or the fore end effects the breech block when different pressures are applied  .

You never ever rest your fore end on anything unsupported, apart from your bipod. On sticks, a fence post or whatever, the fore end should always be cupped by your none shooting hand or something with a little 'give'....certainly nothing solid. 

You can create a consistent and correct eye relief by ensuring there is no blur on any part of the outer edges of the sight picture when zeroing. You then create this same picture for every shot you take, again whether its off sticks, a fence post, back of a camel, whatever. 

[telf]

57 minutes ago, Scully said:

Really? I have zeroed both rf and cf  prone off bipods and then gone on to shoot off sticks, fence posts, gates, Landrover roofs and bonnets, and freehand, and never noticed any difference which made a difference to any quarry I’ve shot! 
Head shot rabbits with my .22 prone have still been headshot rabbits from a vehicle and freehand.

 

👍

[PPP]

Ok, a mixed bag, well off to the (Farm) range later find out ..

[PPP]

Results are in .... makes no difference so it’s obviously just pilot error ...

[wigeon jim]

Are you using quad sticks? If so do not rest the barrel on the front pair,. Jim.

[samboy]

On 02/06/2020 at 19:52, wigeon jim said:

Are you using quad sticks? If so do not rest the barrel on the front pair,. Jim.

I second this.

[welshwarrior]

It’s not to do with scope quality the change  in poi is to do with position if your position is “100 %” correct you will see no change if you have good position and technique as Scully has highlight you will see no real world change. 
 

some people aim off instead of correcting position it’s personal choice how you cut the issue.  
 

personally I zero how I hunt so if you shoot mostly of sticks zero of sticks if you mainly shoot prone zero from prone, if you carry a bench zero from one 😜

Edited June 9, 2020 by welshwarrior

[PPP]

In the end hit was purely down to my muppetness..

[Rim Fire]

i always zero off bipod that way i know the rifle is zeroed if you bye a tidy pair of shooting sticks like the gen 3 primos trigger sticks that way you can adjust the sticks to suit you  in height that way you are square behind the scope so you don't lose parallax