Grouping issues

[griffshrek]

Hello all 

I've reloaded some 143gr Eld-x for a friend of mine and his new rifle . 

During development he's been getting horizontal strings . 

All ammo is cleaned once fired brass all trimmed and COAL is 2.810" 

Rifle is shot off prone with bipod and rear bag 100 m from target 

Below are to diffrent groups of exactly the same powder weight bullet etc .

The difference is the one group is 1.5" below the other 

The horizontal string is shot with 2 minutes between shots,  the standard 3/4" group was shot one after another 

Below is a picture of horizontal string the other group picture hopefully attached below 

Every thing on rifle is tight and has been checked . I'm not shooting the rifle my mate is I always thought horizontal strings were driver error or something loose . 

Can anybody shed any light . 

[griffshrek]

[Popsbengo]

One every two minutes  - could it be wind?

If not I'd suggest tightening the nut behind the trigger 😉

[Ronin]

Driver error

 

Body alignment behind gun and target 

Head alignment with stock - the cheek isn’t in exactly the same place when firing eye position in relation to scope view not consistent 

Horizontal string - he or she is “pushing “ with their shoulder momentarily before the shot released in anticipation of recoil ,,

 

All can be corrected using principles of marksmanship 

 

Couple of videos from Brad Bourner who has provenance of the highest order and runs courses covering these principles mentioned in the videos (in a lot more detail than the video)

 

https://www.shootinguk.co.uk/videos/improve-your-shooting-videos/rifle-skills-get-in-position

 

https://www.shootinguk.co.uk/videos/improve-your-shooting-videos/rifle-skills-tighter-shot-groupings

[Catch-22]

I think it’s very hard to truly diagnose with just two 3x shot groups.

I would shoot some more groups (eg 5x groups) but all from the same position, with as little movement as possible and without too much of a delay between each group. So don’t shoot a group, standup and walk around then shoot some more. Stay prone and focussed on target.

I bet the problem is position, specifically rear bag stability. Concentrating specifically on shooting technique I think should be the first thing to rule out. 

If it’s still not obvious, get another shooter behind the gun and again try some more groups.

If that’s not resolved the problem, then look at the rifle setup in more detail. 

[griffshrek]

Gents 

Thank you for the replies I forgot to add, he that which promotes growth and vigour some 5 shot groups that were exactly the same. 

Fast strings group to a 3/4" 5 shot group, slow shots produce a horizontal string . 

[VarmLR]

You could, in some circumstances, expect a heating barrel and fast strings to have increased dispersion, especially with a light hunting profile barrel that heats up fast, the opposite of what you are experiencing here.  Slower shots resulting in horizontal stringing, as Ronin suggests above, might usually signify more a technique issue.  If it were a scope or mount issue (and I'm not saying it isn't) then I'd expect the same irrespective of grouping string timings.  The low vertical dispersion of the horizontal string might point towards a good consistent load but the horizonal string I've only seen before like that due to two or three things: Shooter technique inconsistency, wind, or the action mounting screws needing torquing up a little.  Of course, if this is happening consistently in spite of who is behind the rifle then it could also point to a barrel issue.  All you can do is start with the easy to check things first and work your way through the list of possible causes until you identify the most likely.

[Andrew]

Inconsistent hold.~Andrew

[justin credible]

Ask someone who is known to be able to shoot properly to shoot the rifle, if they put all the bullets in the same hole then you know the answer. 

[Woodlander]

Inconsistent head position, would be my guess.   I’ve not been shooting for that long and still get horizontal stringing if I’m not concentrating 100%.  

[Montey]

All the above plus  check Parallex adjustment on the scope Parallex isn't there just to make the target look clearer