POI shift ( Windage Only)

[warnera1102]

What can cause a difference in poi specifically left to right?
I'm reloading for. 6.5grendel in a AR platform. Every once in a while I'll get a random flyer left or right, elevation will be perfect.
I use a bubble level and I have seen it shift even with the bubble level in the perfect spot.
My thought is the brass length.
Sammi says case length is 1.516", the chamber will actually handle up to 1.555". The brass hasn't even hit 1.540" yet but I'm curious this is causing the issue due to some of the brass being 1.530" and some being 1.520"
I use a mandrel after full length sizing.

 

[ShtrRdy]

Are you doing any elevation dialing when this happens

Do the shifted shots end up in the same places to the left or right?

 

[warnera1102]

Nope no elevation adjustments.
I can shoot a 3 shot group @100yard ( 1/2moa) then get a flyer 2" left then back to the original poi.

 

[spife7980]

At 1000 yards your bullet hits 2” left and you think it’s the load?

(Also, it’s not brass length)

 

[warnera1102]

At 1000 yards your bullet hits 2” left and you think it’s the load?

(Also, it’s not brass length)

Sorry that was a typo, it should have been 100 yards.
It is corrected now.

 

[Doom]

At 100 yds assuming that nothing is happening to the round like setback its probably the shooter, or the bullet itself which I doubt if its consistently left or right.

 

[nn8734]

What can cause a difference in poi specifically left to right?
I'm reloading for. 6.5grendel in a AR platform. Every once in a while I'll get a random flyer left or right, elevation will be perfect.
I use a bubble level and I have seen it shift even with the bubble level in the perfect spot.
My thought is the brass length.
Sammi says case length is 1.516", the chamber will actually handle up to 1.555". The brass hasn't even hit 1.540" yet but I'm curious this is causing the issue due to some of the brass being 1.530" and some being 1.520"
I use a mandrel after full length sizing.

Prob shooter. Make sure you arent squeezing the grip too hard, introducing tension which can cause you to subtly push the shot left or right, at least in my own experience. Watch the reticle as you squeeze off the shots to make sure it’s not moving slightly left or right upon braking each shot.

Also do a dot drill instead of shooting groups…it helps you stay target focused instead of obsessing (consciously or subconsciously) over group size/shape.

Lastly (if you havent already) check everything over to make sure nothing’s loose (doubt this is the case but you never know).

 

[Doom]

Prob shooter. Make sure you arent squeezing the grip too hard, introducing tension which can cause you to subtly push the shot left or right, at least in my own experience. Watch the reticle as you squeeze off the shots to make sure it’s not moving slightly left or right upon braking each shot.

Also do a dot drill instead of shooting groups…it helps you stay target focused instead of obsessing (consciously or subconsciously) over group size/shape.

Lastly (if you havent already) check everything over to make sure nothing’s loose (doubt this is the case but you never know).

To that point, I had issues with accuracy with the AR. Had someone watch me and they picked up I was gripping the pistol grip differently between shoots. My bolt guns have fairly vertical pistol grips but the AR had more sweep so my thumb was moving to different spots. Replaced with a Magpie K2+ and groups were cut by 1/2 and the gun felt much more comfortable in my hands.

 

[Rhed]

How fast are you shooting the groupings? Could be the heat of the barrel after the 3rd shot. What kind of barrel?

 

[nn8734]

How fast are you shooting the groupings? Could be the heat of the barrel after the 3rd shot. What kind of barrel?

Heat-driven Barrel whip wouldnt come into play until well after the third shot, even for pencil barrels.

More I think about his problem the more i’m convinced it’s shooter. Suppressors can change a load’s precision potential but not by nearly as much what the OP is seeing: if anything it’s usually a very small impact.

Will be beneficial if he shoots dot drills (6 or 9 shots per target, 1” pasties) not groups as it gets the shooter focused on hitting the target (whole point of shooting) vs printing a tiny group (not nearly as important). Will also help if he has a known good shooter with him and/or he films himself shooting to spot any issues with the fundamentals.

Let him do some more shooting with and without the can and report back…the source of the problem should be more apparent once (if) he shares the results/RR.

@warnera1102 - how many rounds down the barrel? Stainless or chrome lined?

 

[Haney]

Could be as simple as grip (pushing/puling) or bipod/bag issue . I would look at your technique and rest, unless you can't get a good group at all . With good vertical I don't think it's the load . Do you have a quality trigger on this rig ?

How is the muzzle blast ? If it's bad you could be anticipating that also .

 

[warnera1102]

How fast are you shooting the groupings? Could be the heat of the barrel after the 3rd shot. What kind of barrel?

A three round group is typically shot within a minute.

 

[warnera1102]

Heat-driven Barrel whip wouldnt come into play until well after the third shot, even for pencil barrels.

More I think about his problem the more i’m convinced it’s shooter. Suppressors can change a load’s precision potential but not by nearly as much what the OP is seeing: if anything it’s usually a very small impact.

Will be beneficial if he shoots dot drills (6 or 9 shots per target, 1” pasties) not groups as it gets the shooter focused on hitting the target (whole point of shooting) vs printing a tiny group (not nearly as important). Will also help if he has a known good shooter with him and/or he films himself shooting to spot any issues with the fundamentals.

Let him do some more shooting with and without the can and report back…the source of the problem should be more apparent once (if) he shares the results/RR.

@warnera1102 - how many rounds down the barrel? Stainless or chrome lined?

I don't have a can on the gun so hopefully that would clear up some issues.
Round count would be around 300 in a stainless barrel (I have the exact number in my book).
Maybe this will help (or hurt) the discussion.

Another reason I am thinking brass prep and maybe a shooter issue or a combination of both. I shot the far right group at 511yards prone (taking my time) to get dope on the gun( shots 2-6). The shot above the group was shot 1 then I adjusted my elevation.
I grabbed another round of a different lot of brass that was not the same length trimmed but loaded at the same time (same lot powder, primer and bullet) and I got shot labeled number 1 to the left .
Now there was 0, i mean 0 wind, and what wind I did have was from the left @ 10 oclock.

 

[nn8734]

I don't have a can on the gun so hopefully that would clear up some issues.
Round count would be around 300 in a stainless barrel (I have the exact number in my book).
Maybe this will help (or hurt) the discussion. View attachment 7940122
Another reason I am thinking brass prep and maybe a shooter issue or a combination of both. I shot the far right group at 511yards prone (taking my time) to get dope on the gun( shots 2-6). The shot above the group was shot 1 then I adjusted my elevation.
I grabbed another round of a different lot of brass that was not the same length trimmed but loaded at the same time (same lot powder, primer and bullet) and I got shot labeled number 1 to the left .
Now there was 0, i mean 0 wind, and what wind I did have was from the left @ 10 oclock.

Measuring shot groups at 500y plus for purpose’s of tracing said group size to an ammo production issue is pointless. Trim length variance (unless its literally Yuge) wont make any difference either.

All the target tells me is that the load appears to be performing fine but you didnt hold quite enough for l-r wind/spin drift.

When you mention wind, are you referring to wind patterns at the FFP?

How do you know there was no wind down range?

Did you observe mirage patterns and/or wind indicators such as contractor ribbon hanging on the target stand?

 

[warnera1102]

Measuring shot groups at 500y plus for purpose’s of tracing said group size to an ammo production issue is pointless. Trim length variance (unless its literally Yuge) wont make any difference either.

All the target tells me is that the load appears to be performing fine but you didnt hold quite enough for l-r wind/spin drift.

When you mention wind, are you referring to wind patterns at the FFP?

How do you know there was no wind down range?

Did you observe mirage patterns and/or wind indicators such as contractor ribbon hanging on the target stand?

I was using this as an example of what I see at 100 yards, a random but consistent 1 moa shift.

 

[nn8734]

I was using this as an example of what I see at 100 yards, a random but consistent 1 moa shift.

Next time you go out w/it, confirm your zero then Shoot a dot drill at 100 next time and see what the target looks like. Id do 9 pasties (3x3) or 10 (5x2)

Then have someone else run the same drill and see if the poi shift shows up with the other shooter’s target. If so, then perhaps it systemic (rifle, optic, ammo). But my guess is it won’t.

 

[warnera1102]

Next time you go out w/it, confirm your zero then Shoot a dot drill at 100 next time you go to the range and see what the target looks like. Id do 9 pasties (3x3) or 10 (5x2)

Then have someone else run the same drill and see if the poi shift shows up with the other shooter’s target. If so, then perhaps it systemic (rifle, optic, ammo). But my guess is it won’t.

Will do!
I appreciate it.