Long range verification

My guess is spin drift, and possibly some wind that you can't see or feel from your shooting position. I've also had this issue when the parallax wasn't aligned with my yardage.

You must have a solid 100 yard zero. One or two shots close to bullseye is not good enough.

If you have windage change at distance it can mean that your scope and bore are not perfectly aligned. Not all actions are perfect and not all scope rails are perfect. A set of Burris rings with inserts can fix your problem.

Or just toss that supressor in the ditch, go back to a brake and be happy . Only partly kidding. I think all the others are spot on. I have the worst results with supressors. My rifles shoot completely different with them but I will say that if your zero is slightly right it will correlate way down range. May just look like it's trending on the right side of the POI dot at 100 but even a 1/4 minute that's hardly noticeable at your 100 yard zero gets exponentially larger. It's happened to me. If everything else is checking out I'd shift my zero slight and see how it affects groups stepping out.

sqearl said:

Hey guys need some help. I've just gotten my new suppressor spun it onto my Christensen 300prc. I've dialed it in dead nuts at 100 yd. Then I shoot it at 500 yd. High and right. I try at 1000, high and right. Now the elevation I can dial in. The right has me baffled especially when it is zero at 100. Does anyone have any insight or advice I could use. Thank you in advance

Click to expand...

At a 1K yds you will have 6 to 7" spin drifts and if your scope is not plumb with you rifle that will also throw it off if your scope is 5 degrees off at a 1K yds your looking at around 24to 30"

Tommy T said:

At a 1K yds you will have 6 to 7" spin drifts and if your scope is not plumb with you rifle that will also throw it off if your scope is 5 degrees off at a 1K yds your looking at around 24to 30"

Click to expand...

Do a tall target test to see if your perfectly plumb. It will also give you info on offset to plug into your ballistic app.

sqearl said:

Hey guys need some help. I've just gotten my new suppressor spun it onto my Christensen 300prc. I've dialed it in dead nuts at 100 yd. Then I shoot it at 500 yd. High and right. I try at 1000, high and right. Now the elevation I can dial in. The right has me baffled especially when it is zero at 100. Does anyone have any insight or advice I could use. Thank you in advance

Click to expand...

Very seldom does a rifle have the same exact zero at different ranges. Elevation changes, usually the bullet drops unless the zero you are using for the different ranges is off, which is often the case. Just because your ballistics chart says that the drop will be this, and you dial it in only to find that it isn't working is not unusual. I would suspect that the elevation zero you are using is off causing the hit to be high. Simply reset the zero you are using at that range to correspond with the hit and that will take care of that problem. The drift to the right, is just that. Spin drift is often overlooked but at longer ranges there are other factors that come into effect, also often overlooked. Wind is a big factor. It may be dead calm on the firing line, but between you and the target the wind can vary, and even reverse itself as the bullet progresses to the target. There were many times when shooting competition when the wind flags along the range showed different direction and speed. I remember once when shooting 600 yards that the wind was off my back on the firing line, halfway down range it was showing 10 mph from the right and at the target it was showing 5 mph from the left. This often happens when you are shooting at a range that is located in a valley or other constricted terrain.

Other things that you might not have encountered or paid attention to is light and mirage. In bright light you can see the target better so your point of aim, be it 6 O'clock or center, you can see better so your hold is going to be tighter thus more accurate. When the light gets darker then you can no longer see the target as clearly so you cannot hold as accurately, your shots will not group as tight as they do in bright light.

Mirage is an optical illusion caused by the heating of the ground under the path of the bullet, causing the air to rise and cause visible (usually under magnification) waves of air currents to rise from the ground into the sky. (Heat rises) and causes the optical illusion that makes the target seem, where it is not. Instead of me trying to explain this phenomenon, I am going to refer you to a video. (a picture is worth 10,000 words)



This is one of the excellent videos available from Midway USA. They have a whole series of videos that explain shooting issues in a manner that is easy to understand. They are very worth your time to review.

Remember, every time you are at the range, you are in competition with yourself. Make each and every shot count and strive to make every shot better than the last.

I suspect you are canting your rifle to the right. When you dial up for elevation this causes your impacts to hit high and right.

Wind could be a factor, but unless you are dealing with vertical wind like in a canyon shouldn't have a big effect on your elevation. Are you measuring wind with a kestrel and inputting it into a ballistic calculator that is correcting for aerodynamic jump and Coriolis? Won't have a big effect at 500, but will be significant at 1000 yds.

I already seen it mentioned once. I was going to write the same thing. Take it to an area where shooting is nice and comfortable and where you can really get behind the rifle naturally. Build a shooting position with natural point of aim and then do a tall target test. It can be done at 100 yds if needed.

Ensure when you shoot your groups that you're taking your time and applying all of the fundamentals of marksmanship. Ensure you have proper eye relief and you're not holding your head off the rifle to account for poor eye relief. Make sure your parallax is properly adjusted, ensure your rifle is level. If you have a clean vertical line without left or right deviation between your groups, then it's probably spin drift as mentioned.

Start simple and diagnose at close range. It could be your level...assuming you're using one, is not true to your scope or your scope is not true to your scope base, or both, meaning the horizontal of your reticle is not parallel to your scope base. This doesn't matter if you have a 0 Moa base, but the minute you add MOA/ angle to your base, you have to be truly leveled. Every click of elevation on a scope that isn't trued is a partial windage adjustment. What I mean is, if your scope is angled slightly to the right, maybe imperceptibly so, then when you dial up 1 moa you're not actually moving the shot up 1 whole moa, your moving it up say 9/10 and moving it right 1/10.... Tall target test it. Also, it wouldn't hurt to do a turret tracking test afterward.

Also, 1 thread per subject there Bubba.

I responded to your other thread.

Definitely verify your scope is tracking. A lot of scopes do not dial exactly. They also can have horizontal error when you only dial vertical. Think of it like a can't problem. I have a Leupold vx 5 that has almost 3% verticle error. Know that I know I can adjust my app to control for it. Fortunately no horizontal can't for me.

T3ninja said:

I'll throw a wrench in here and suggest maybe a little rifle cant into the mix for the right.

Click to expand...

This was my guess too

Tall Target Test.

How far right and how high at 500 and 1000 from expected?