Gun groups better @ 200 than 100yrds

[Pdvdh]

In theory I think it would be impossible without a guidance system to make groups smaller (in terms of measured inches) as distance increases.

Agreed.

 

[WildRose]

I've heard a theory that some of the VLD bullets do not stabilize well before 200yds causing groups to then tighten at longer ranges (beyond 100yds). I've never been able to wrap myself around that theory though or seen any evidence that it's true.

I'm with the others. My bet is it's a parallax issue or shooter issue especially with so little data to work with here.

 

[Greyfox]

I've heard a theory that some of the VLD bullets do not stabilize well before 200yds causing groups to then tighten at longer ranges (beyond 100yds). I've never been able to wrap myself around that theory though or seen any evidence that it's true.

I'm with the others. My bet is it's a parallax issue or shooter issue especially with so little data to work with here.

I have have seen this effect and understand that it is a bullet stabilization issue usually caused by a bullet that is at the limit of compatabilty between the rifle twist rate and the weight/ length/velocity of the bullet. I specifically saw this and reproduced it when I tried shooting 75gr bullets out of my 223 with a 1:9 twist. It produced .75" at 100 yards and .5" at 200. I had the same effect shooting 175 SMK's out of my 1:12 twist 308. 1" at 100 yards, 1" at 300 yards, consistently. Also seen it on several occasions with the bench rest guys at my club. It's likely why that box of Bergers designates why you need to use a minimum twist rate with a particular bullet
I agree that there is not enough statistical info to prove that it is the issue described
in the original post.

 

[WildRose]

I have have seen this effect and understand that it is a bullet stabilization issue usually caused by a bullet that is at the limit of compatabilty between the rifle twist rate and the weight/ length/velocity of the bullet. I specifically saw this and reproduced it when I tried shooting 75gr bullets out of my 223 with a 1:9 twist. It produced .75" at 100 yards and .5" at 200. I had the same effect shooting 175 SMK's out of my 1:12 twist 308. 1" at 100 yards, 1" at 300 yards, consistently. Also seen it on several occasions with the bench rest guys at my club. It's likely why that box of Bergers designates why you need to use a minimum twist rate with a particular bullet
I agree that there is not enough statistical info to prove that it is the issue described
in the original post.

Agreed, I have no problem really accepting that. What I have a problem with is the idea that the stabilization issue can be so severe as to produce measurably smaller diameter groups at the greater ranges.

I've watched armor piercing rounds (great big arrows/darts) that looked like they were all but tumbling for a couple of hundred yards finally stabilize and fly like a thrown dart.

However the impact didn't vary greatly because the point held very closely to the center line all the way.

 

[rscott5028]

Anybody can get lucky and shoot a tiny group at a long distance.

If you consistently (meaning statistically significant) shoot smaller MOA groups at longer distances than you do at shorter distances, then the most likely cause is parallax.

I'd be keen to hear other theories. But, I don't subscribe to the wobbly bullet going to sleep theory as an explanation for this phenomenon.

-- richard