Bullet stability question

[Smokin7s]

I had a 6cm rifle built in January and I had the guy that built it work up a load with it, Berger 105 lapua brass running 3023 average. I’m not the best shot by any means but I’m decent enough. My question is why is the rifle shooting .6moa at 100 and .3 at 300 or 400?
The guy that built it said that these high bc bullets sometimes don’t go to sleep until 200 yards?

Is there something to this or am I just in my head at 100 trying to shoot groups?

 

[Maxduty]

Because you have less target to look at at 3 or 4 hundred. Lowlight commented on this a while back in another post. You're trying too hard on the 100 yard target because you can see it is basically what I took away from it. But bullets don't "go to sleep". In all actuality, you're groups should open up slightly larger than double due to shooter input and ballistics at longer ranges. I'd ascertain if you can consistently shoot tighter groups at longer ranges or if this was just a fluke grouping.

 

[spife7980]

or am I just in my head at 100 trying to shoot groups?

Yes

 

[supercorndogs]

How many shots have you fired at 100 vs 3 or 400?

 

[Smokin7s]

Because you have less target to look at at 3 or 4 hundred. Lowlight commented on this a while back in another post. You're trying too hard on the 100 yard target because you can see it is basically what I took away from it. But bullets don't "go to sleep". In all actuality, you're groups should open up slightly larger than double due to shooter input and ballistics at longer ranges. I'd ascertain if you can consistently shoot tighter groups at longer ranges or if this was just a fluke grouping.

No it’s pretty common I’ve tested it a lot normally.3 out there .6 up at 100

 

[oldfatguy]

Because you have less target to look at at 3 or 4 hundred. Lowlight commented on this a while back in another post. You're trying too hard on the 100 yard target because you can see it is basically what I took away from

Crank your magnification down to shrink the image at 100.

OFG

 

[Ledzep]

I have a suspicion that parallax causes a lot of these reports too. Combined with small sample size groups it's easy enough to convince yourself it's reality.

Bullets do transition to dynamic stability and do experience precession after exciting the muzzle with exit yaw. That does typically take 150-200yd to settle out. However, the yaw/precession describes the orientation of the bullet (where it's axis is pointing), not its position or trajectory necessarily. The bullet does not travel in a decreasing radius spiral, it (bullet's CoM) travels along a pretty flat arc as you'd expect, while it points in a decreasing magnitude spiral until it becomes dynamically stable.

TLDR: Something on the shooter, optics, or sampling size side of things is causing bigger groups at closer range.

 

[Steel head]

When I first start playing with rifles seriously I saw that phenomenon a lot.
Pretty much never see it anymore so bullet manufacturers must have fixed the bullets or something.

 

[RTH1800]

Optical or emotional.

 

[Smokin7s]

Optical or emotional.

I’m thinking it’s gotta be in my head or my hands I’m shooting a Schmidt pmii