Will different .22LR ammo shoot horizontally different?

[tulazhen]

Today there was nearly no wind on the range, and I tested several ammunitions with a single shot rifle, 5 to 10 rounds for each at 100 yards. The rifle was on a bipod.

Strangely, when the rifle was zeroed with one ammo, it could shoot 2-3 inches right or left with another. It was not about outliers, but the whole group wandered horizontally, sometimes pretty tight.

The scope was not loose, either. Wandering vertically is understandable due to the load, but, horizontally?

Was it normal, or could anyone suggest the possible cause?

Thanks!

 

[Evanguy]

that happens. sometimes its left, right, high or low. my rifle has shot low with ammo that was 150fps faster. 2" is about the max I've seen it move around, often its less.

 

[emerson]

Today there was nearly no wind on the range, and I tested several ammunitions with a single shot rifle, 5 to 10 rounds for each at 100 yards. The rifle was on a bipod.

Strangely, when the rifle was zeroed with one ammo, it could shoots 2-3 inches right or left with another. It was not about outliers, but the whole group wandered horizontally, sometimes pretty tight.

The scope was not loose, either. Wandering vertically is understandable due to the load, but, horizontally?

Was it normal, or could anyone suggest the possible cause?

Thanks!

Yes, same for me.

 

[tulazhen]

Thank you for the quick reply guys. My friend also said it could happen. It looks that all I should do is adjusting the scope and practice.

Out of curiosity, what is the science in it? BTW the rifle has a heavy barrel.

 

[JEC]

I really don’t know … but one time read that a vibration is set in the barrel as the bullet passes from the chamber into the bore … so it is possible the bullet is exiting when the muzzle is at a different point in the vibration.

 

[adamg]

Yes, that happens. I know my same rifle sees a zero shift of about 0.4 mrad going between two brands of 22lr ammo.

 

[Odinson]

I have seen a similar thing with different brands of ammunition, surprisingly, the most accurate ammo is Remington Gold ...... the ammo that people call junk. Seems that every gun has its favorite.

 

[hammering hank]

Certainly yes thats normal, and that one ammo may shoot great out of said rifle and not so much another. I look for the tightest group and re-zero to that ammo for my hunting 22s, plinking guns i zero with my bulk ammo

 

[grauhanen]

Today there was nearly no wind on the range, and I tested several ammunitions with a single shot rifle, 5 to 10 rounds for each at 100 yards. The rifle was on a bipod.

Strangely, when the rifle was zeroed with one ammo, it could shoot 2-3 inches right or left with another. It was not about outliers, but the whole group wandered horizontally, sometimes pretty tight.

The scope was not loose, either. Wandering vertically is understandable due to the load, but, horizontally?

Was it normal, or could anyone suggest the possible cause?

Thanks!

There are a couple of possible explanations for why different .22LR ammos have different POIs.

An obvious reason is that despite there being "nearly no wind on the range," the still is some wind. Even a little bit of wind can push a .22LR round. A difference of only one mph in crosswind is not noticable for most shooters. Without windflags it's hard to detect winds under 3 or 4 mph. Consider that a change of only 1 mph in a crosswind that occurs between two groups will move POI by over .4". In other words, for every 1 mph difference in wind between groups, there will be a .4" difference in wind drift. If it's 2 mph, a POI change of over .8" can be expected.

A second common reason why POI changes between groups is that the shooter/rifle changes between groups. For each new group shot, the shooter moves the rifle. It may seem like everything is as before, but it often isn't as it seems. This is why many shooters will see group POI drift even at 50 yards.

Another reason is that bores and different bullets often don't react consistently. The bore remains the same, but when different ammo is used the bullets may not be the same. While they may look the same, there can be differences in dimensions, weight, and composition. These can contribute to some bullets behaving differently in the same bore.

I have seen a similar thing with different brands of ammunition, surprisingly, the most accurate ammo is Remington Gold ...... the ammo that people call junk. Seems that every gun has its favorite.

Most .22LR shooters don't expect to hear that Remington Golden Bullets is the most accurate .22LR ammo in any rifle.

 

[CZ Shooter]

Thank you for the quick reply guys. My friend also said it could happen. It looks that all I should do is adjusting the scope and practice.

Out of curiosity, what is the science in it? BTW the rifle has a heavy barrel.

It is barrel harmonics....if the fps are different, the barrel whip will be slightly different and the bullet will exit at different point of this whipping action.

There are more factors involved, but this would be one of the main ones.

 

[Jahnj0584]

I had it happen too. At 100y the bulk 308 shoots 3" to the right. Hunting ammo is dead center - not sure why it happens! Obviously they have the same "energy " otherwise elevation would change.

 

[horseman2]

My example of this drastic shift was while testing CCI MiniMags in a Ruger 10/22 at 100 yards.
Sighted in for round nose the groups were in the 2" range.
With Hollow Point, the group was six inches to the left and ballooned to 6" and this was repeated.
Is it fair to say the center of a 6" group was six inches to the left . . . close enough for the girls I take to the range!
Since I shoot a lot of match grade ammunition, shifts are seen between different lots although sometimes to a lesser degree.

 

[grauhanen]

It is barrel harmonics....if the fps are different, the barrel whip will be slightly different and the bullet will exit at different point of this whipping action.

There are more factors involved, but this would be one of the main ones.

Barrel harmonics doesn't explain why some groups are to the left or right of the POA.

When the MV is different for almost every round, it can't explain POI change for different groups, even of the same ammo. For example, if a box of good match ammo has an extreme spread of 35 fps, very few will have equal MVs. Yet if all 50 rounds were shot at the same POA, most would go where expected.

To illustrate, see the example below in which the ammo used had an ES of 45 fps and a not-so-good SD of 10 fps, neither of which is unusual for entry level match ammos. Only two rounds of 50 went somewhat outside the group the other 48 made.



The cause of POI shift in the OP's case is better explained more prosaically by wind (even if it doesn't seem to be significant), shooter/rifle change, and differences in ammo.

 

[tulazhen]

Thanks for all the replies!

I will try again at 50 yards first and then move to 100 yards.

 

[OkayShooter]

Could be different weight bullet or different bullet design, that cuts thru the air differently. Or slightly smaller bullet that the rifling doesnt grip the same.

 

[tulazhen]

There are a couple of possible explanations for why different .22LR ammos have different POIs.

An obvious reason is that despite there being "nearly no wind on the range," the still is some wind. Even a little bit of wind can push a .22LR round. A difference of only one mph in crosswind is not noticable for most shooters. Without windflags it's hard to detect winds under 3 or 4 mph. Consider that a change of only 1 mph in a crosswind that occurs between two groups will move POI by over .4". In other words, for every 1 mph difference in wind between groups, there will be a .4" difference in wind drift. If it's 2 mph, a POI change of over .8" can be expected.

A second common reason why POI changes between groups is that the shooter/rifle changes between groups. For each new group shot, the shooter moves the rifle. It may seem like everything is as before, but it often isn't as it seems. This is why many shooters will see group POI drift even at 50 yards.

Another reason is that bores and different bullets often don't react consistently. The bore remains the same, but when different ammo is used the bullets may not be the same. While they may look the same, there can be differences in dimensions, weight, and composition. These can contribute to some bullets behaving differently in the same bore.



Most .22LR shooters don't expect to hear that Remington Golden Bullets is the most accurate .22LR ammo in any rifle.

You are right, the wind was still a factor. I have a Kestrel and could see the 90 degrees wind speed was up to 2 miles at the firing line. I did notice sometimes the flag was a little up. It could cause 1 inch drift at 100 yard.

The reason for the rest of the drift like 1-2 inch was unknown. As you said, the ammo, changed position, and slightly canted bipod could concur. When shooting centerfire rifles, I didn't see horizontal shifts (center of groups).

thanks a lot for the analysis.

 

[CZ Shooter]

Barrel harmonics doesn't explain why some groups are to the left or right of the POA.

When the MV is different for almost every round, it can't explain POI change for different groups, even of the same ammo. For example, if a box of good match ammo has an extreme spread of 35 fps, very few will have equal MVs. Yet if all 50 rounds were shot at the same POA, most would go where expected.

To illustrate, see the example below in which the ammo used had an ES of 45 fps and a not-so-good SD of 10 fps, neither of which is unusual for entry level match ammos. Only two rounds of 50 went somewhat outside the group the other 48 made.



The cause of POI shift in the OP's case is better explained more prosaically by wind (even if it doesn't seem to be significant), shooter/rifle change, and differences in ammo.

You are likely correct in most of what you are saying, however the barrel whip effect cannot be denied, as the different energy loads will exit at slightly different points of the whip cycle.

I think this would be more pronounced when shifting between SV and HV loads as the differences can be over 200 fps.
It is all about timing and consistency.

 

[Grizzlypeg]

I find that even a barrel that has sat unused for a while, shoots to a slightly different point of impact until a couple of rounds are shot through it. I see this in my CZ452 and Ruger 10/22 with Green Mountain heavy barrel. I resist the temptation to adjust the scope, but simply fire a few shots and they walk their way back to the bulleye. It's slighly problematic when you fire your first shot at a gopher at 75 yards and miss.

 

[Odinson]

There are a couple of possible explanations for why different .22LR ammos have different POIs.

An obvious reason is that despite there being "nearly no wind on the range," the still is some wind. Even a little bit of wind can push a .22LR round. A difference of only one mph in crosswind is not noticable for most shooters. Without windflags it's hard to detect winds under 3 or 4 mph. Consider that a change of only 1 mph in a crosswind that occurs between two groups will move POI by over .4". In other words, for every 1 mph difference in wind between groups, there will be a .4" difference in wind drift. If it's 2 mph, a POI change of over .8" can be expected.

A second common reason why POI changes between groups is that the shooter/rifle changes between groups. For each new group shot, the shooter moves the rifle. It may seem like everything is as before, but it often isn't as it seems. This is why many shooters will see group POI drift even at 50 yards.

Another reason is that bores and different bullets often don't react consistently. The bore remains the same, but when different ammo is used the bullets may not be the same. While they may look the same, there can be differences in dimensions, weight, and composition. These can contribute to some bullets behaving differently in the same bore.



Most .22LR shooters don't expect to hear that Remington Golden Bullets is the most accurate .22LR ammo in any rifle.

It surprised me too.

 

[easyrider604]

You are likely correct in most of what you are saying, however the barrel whip effect cannot be denied, as the different energy loads will exit at slightly different points of the whip cycle.

I think this would be more pronounced when shifting between SV and HV loads as the differences can be over 200 fps.
It is all about timing and consistency.

I agree with this theory. All barrels will whip to some extent. Depending on where the muzzle is pointing when the Bullet exits,will determine the group or lack thereof. This may be why barrel tuners are installed.