Range Report Bullets drifting right...Spin drift?

[ponchair]

I have noticed my rifle will shoot consistent .75 moa groups, vertically and horizontally perfect @ 100 yards, but when I shoot @ 500 yards I am getting a huge drift, 2 MOA to the right. I was thinking it was just me, but it happens to everyone that has shot the rifle. Any thoughts?

My rifle: Armalite AR-10, noveske barrel.

Load: 155 scenar, 2725 fps.

 

[Bevan]

Re: Bullets drifting right...Spin drift?

not spindrift, not that magnitude of error at that range


scope canted or doesn't track straight

wind

 

[chawk]

Re: Bullets drifting right...Spin drift?

I would think Bevan is on the right track. Is your reticle squared up to the rifle and level when shooting? If so, have you tried shooting at 500 yards using a holdover instead of dialing the elevation? Still hit 2moa right?

 

[BryanLitz]

Re: Bullets drifting right...Spin drift?

I agree. Spin drift should only be about 0.3 MOA at 600 yards. 2 MOA implies a problem with the scope.

or,

Is there a prevailing wind?

 

[ponchair]

Re: Bullets drifting right...Spin drift?

I was using a hold over at first, and 2 MOA made an impact every time. Then I adjusted the turrets to 2 MOA and again nothing but impact occurred.

Bryan...the wind reading I was getting was 1-2 mph from right to left, which was 50 to 100 yards in front of the muzzle. The range has berms on both sides with grass on top and the wind was exactly the same on top as it was on the ground. The berms are roughly 12-15 feet tall.

I guess I am just a bit frustrated, and I would weigh that it was shooter error, but to have other experienced shooters get the same results makes me scratch my head.

 

[Bevan]

Re: Bullets drifting right...Spin drift?

Has this happened a lot or just on one range trip

 

[Raven 6]

Re: Bullets drifting right...Spin drift?

I would say its more in the barrel if this is something that happens every time you go to the range. Have you shot it at say 200-300yrds and noticed shooting to the right but only about half the distance you are hitting at 500?

 

[ponchair]

Re: Bullets drifting right...Spin drift?

Has happened on more than one occasion. Needless to say 100% of the time.

Triple 6, good question, I rarely shoot anything closer than 500 yards, unless it is 100 to confirm zero and do the 1 MOA dot practice. I will have to give that a try and see how things add up.

 

[Raven 6]

Re: Bullets drifting right...Spin drift?

What I am thinking is that the bore rarely runs with the o.d. and if the bore is arching right the further you shoot the more you will be to the right of your zero at 100 yards. When we build rifles the arch is timed to be up thus using less if your scope elevation. It is only minor but it is there.