215 Berger stability Q

[rafterfp]

Im running 215 Bergers in a 28 inch bartlein 10 twist.
I zero everything at 200 yrds, never shoot 100.
This set up is consistent 1/2 moa performer out to 1,000.
My question is..... I recently shot a few 100 yard groups with
This rifle/bullet combo and could not get better than 1.5 inch
groups. My elevation is 4,700 feet and my load velocity is 2950.
Is it normal for the 215 to need some time to stabilize? Or is
my 10 twist not stabilizing them properly?

 

[Mikecr]

Another case of shrinking moa with distance.
It isn't stability, and pretty much everyone who hasn't seen it denies it can happen.

I zero at 200 also, and shoot way better in moa at 300yds -vs- 100yds, but I have not determined the cause yet. All I know is that it's not my shooting system.
If you figure it out, let us know.

 

[ohiohunter]

Its asleep

 

[FURMAN]

like Mikecr said if you figure it out I would love to know. I am seeing this with my 300 WM and one barrel in my 7-300. Years ago Bryan Litz theorized it was due to optical swerve but recently he proved that not to be the case. Like Mike said people who have not seen it don't believe it. In the end it is the main reason I prefer load development with a ladder then zero at two and shoot.

 

[Mikecr]

Epicyclic Swerve.
It's not that, or going to sleep, or anything about bullets/stability at all. Berger proved that much.
Barrel whip/tune could contribute to it in vertical, but not nearly so much.
For me, I have a theory about parallax and my glasses. But how & the hell could I ever prove that to anyone? I can't see well enough to prove it to myself..

 

[FURMAN]

Ha, I did not notice. I must have spelled it incorrectly and auto correct "fixed" it. I have two barrels that do it. One is on a rifle that the second barrel does not and I am sharing scopes.

 

[Jerry M]

As stated in the post above: is that the bullet goes to sleep at the longer range, where it is not settled at the closer range. It is a term used by Palma Shooters who's closest range is normally 800 yards. I had a 6.5-06 that did the same thing.

Good luck

Jerry

 

[CA48]

I have a 338 EDGE AI that shot .5-1" groups at 100yds with 300gr bergers and it will shoot consistent 0.5 inch not moa groups at 300yds also. I changed my seating depth and powder charge until I found a sweet spot 1/4 moa accuracy and less at 100. It took a while to find this load. This is an accurate rifle and will easily shoot .5moa and less with a wide gap of powder charges and seating depths but it has always grouped big up close and tiny at distance. I feel like the harmonics of a 30" long sendaro contoured barrel are playing a big role in this situation.

 

[Mikecr]

I have a 338 EDGE AI that shot .5-1" groups at 100yds with 300gr bergers and it will shoot consistent 0.5 inch not moa groups at 300yds also. I changed my seating depth and powder charge until I found a sweet spot 1/4 moa accuracy and less at 100.

So to be clear on this, are you saying you found a load that shoots great at 300, but had to find a different load to shoot great at 100? What did that 100yd load shoot like at 300?
What was the difference in group SHAPEs (vert/horiz)?

 

[CA48]

Yes, when I developed that 100 yard load that shot well I started shooting steel courses and never measured groups since then on paper at 300 yards. But at a friends course where I shot the most I would check my zero on an 8in plate at 350yards. 3 shot groups would measure .3 to .4moa in calm conditions. That is just measuring with my FFP MOA reticle at that time though. But now my barrel has 2300 rds on it and accuracy has faded to .5moa at 100yds and it also holds .5moa at the further distances at present. So if I shot now at 300 to check group size it really wouldn't be a fair comparison.

As far as the difference in group shape at 100 my load that shot .5-1 moa would ussually group with first 2 shots touching and impacting at POA and the third shot would be high 12 o clock. I can't remember what the vertical/horizontal looked like on my 100yd load that would shoot .2-.3 moa it's been awhile. I use this rifle as a hunting and steel gun so it doesn't get shot on paper much anymore.