Over the past cpl wks I have been working up a load for my .30-06. I am shooting the Barnes TSX 168gr bullet at 2830 fps. At 100 yards groups have been stellar, all sub MOA and a couple under 0.5." Confident that this would be this year's hunting load, I moved out to 200yrds.

200 yrd groups are 2.25" The load will probably do better, but unfortunately I am the limiting factor... As expected, I had a 2.5" drop. What surprised me was that my POI also shifted to the right nearly 3 inches. I am exactly 1.5" directly over the bull at 100. At 200 I'm an inch low and 2.75" to the right. Three groups fired on two different days (both in perfect conditions with less than a 2mph wind) yielded the same results.

Is this change in windage from 100 to 200 common? Should I move my POI to 1" left at 100 so that I'm 2" right at 200? Am I most likely going to be 6" right at 300? Should I start over with a new load or is it a function of the rifle? Action screws, scope mounts, everything seems tight and in place.

Any thoughts?

I would guess that it's not the load but either the way your shooting or maybe your scope is not level and your canting the rifle a lot. To move 2 3/4" off track in 100yds is highly unlikely. It's also possible that the scope mounting has a problem and the scope might have moved just a bit, doesnt take much to really screw things up.

If your shooting off of sandbags, which I'd guess you are, are you resting the stock on the bags or holding it down on the bags? Do you grab the rifle over the barrel in front of the bags? Thats a no-no. Are you keeping the sling swivel stud off the bags? Could be a number of things but I doubt the load.

Cant, the word not the contraction. The rifle/scope combination is not plumb to the target reference.

Thanks guys. I was indeed shooting off bags. I was ever so lightly holding the forend of the rifle just in front of the magazine. The bags were just in front of my left hand (I'm righ handed). The rear bags were just under the pistol grip. I don't think I'm canting the rifle. Especially since I have so consistantly reproduced the results. Hard to believe I would cant it the same on both days.

308Sako, your comment makes great sense. The scope is a 4200 Elite mounted with the "old style" Sako rings on a .30-06 Finnbear. The mounts are tight. But what you're saying is that my scope must not be directly parallel to my barrel?

Any suggestions on how to diagnose whether my scope is left or right of the barrel?

Thanks again guys. This is starting to make sense...

I think what they are saying is the scope is rotated about its "line of sight centerline" in the rings. When the crosshair is vertical, the rifle is not. Hitting the paper to the right would tell me the scope is rotated a bit CCW in the rings.

Hope I'm not really mucking things up. Correct me if I'm wrong...

How much cross wind do you have?

quote:

Originally posted by Devildawg66:
How much cross wind do you have?

Downrange, not just at the muzzle.


Okie John

My Davis Weather Station measured the 10min average wind speed at 2mph on both days. It was very calm. My buddy and I both commented on what a perfect day it was for shooting.

Next week I'm going to have him shoot the rifle. Heck, it's probably just me. If the same happens for him, I'll start looking at the scope closer.

Thanks again.

quote:

Is this change in windage from 100 to 200 common?

Oh Yeah, I just get a grin when I hear fellas at the range say "I got her dead center and 2" high at a hundred, she's gonna be real close out to 300."

The only way to know what a bullet is doing at a certain range is to shoot it at that range however, if you can't shoot at your range out at 300 and 400, but can shot to 200. The 200 yard targets will give you a much better guestimation of what the load will do at alittle longer ranges. 100 yards doesn't tell you squat most of the time.

My advice would be to forget you 100 yard POI and zero at 200. Once you are dead zero at 200 everything inbetween is going to be so close it will not matter unless of course you are trying to shoot them in the eye socket .

I've seen rifles that shot quite good groups at 100 only to see the groups fall apart at 200. One that comes to mind is a 30-06 I shot rescently w/ 150 partitions. It was sub-moa at 100 and shot 3-4" at 200! That'll sure get you agravated. A rifle that shoots 1/2" at 100 will not shoot 1" at 200 many times contray to what many believe. Sometimes they will, sometimes they will not.

Good Luck

Reloader

Zero the wincage at 200 then shoot it at 100 and see what happens.

quote:

I am exactly 1.5" directly over the bull at 100. At 200 I'm an inch low and 2.75" to the right. Three groups fired on two different days (both in perfect conditions with less than a 2mph wind) yielded the same results.

Yep. This why I always tell a person to confirm their initial zero by firing at longer ranges, if possible. Especially the guys who zero their rifles at 25 yards, then depend on a ballistics table to tell them where their bullets will be striking out yonder! Even if the tables manage to be correct for elevation (but usually aren't!!) the windage is often off by a considerable amount......

So, as mentioned above, do your windage adjustments at 200 yards, then shoot a round or two at 100 to see what the difference is, if any......

Thanks guys. Weather and wife permiting, I'm going to try to get back to the range on Sunday. I'll move 4 clicks to the left and then see where she's at at 100 & 200. I'll let ya know what I learn.

Check an see if you have much more parallax at 200 as compared to 100 yards.

Did you change your elevation setting at all between 100 and 200 yards?

If so, Your scope may bave been firmly mounted, and you may be holding the rifle without "canting" it. BUT, the reticule in your scope may not have the vertical crosshair plumb to the bore. In other words, when you add elevation to the adjustments to go from 100 yards to 200 yards, you may be clicking both up and right at the same time.

Of course, if you got up to go down range and put up a new target, your position when you sat back down at the bench may have changed enough to cause the difference. That's particularly possible if you are using a sand bag rest and racked your rifle while down range. When you put the rifle back on the bags, all kinds of things may have been different in where and how firmly the bags touched the rifle, and how you were sitting relative to the rifle.

You would be surprised how many people bring their rifles to me that have the scopes mounted crooked. Just throwing the gun to the shoulder shows crosshairs on an angle. Automatic cant when you level the crosshairs on a target. Use a level on the gun mounted in a vise and a vertical line on a wall to see where the crosshairs are.
Most people do not shoulder a rifle vertically and adjust the scope to a crooked gun.

A BIG thanks to all for talking me through this. As usuall, I made it WAY more complicated than I had to. So here's my thought process.

I was basing my windage "perfection" at 100yrds on a single group. I was 0.6 inches at 100 yrds. Pretty much directly over the bull with two, and the third half an ichh to the right. At 200, I'm 2.5 to the right x 3 groups. Instead of questionining the 200 yrd groups, I should have reproduced the 100yrd group.

So... I moved my scope four clicks to the left and went to the range. Three rounds at 100 yards printed 0.48." Just a shade (0.4)" to the left and 1.5" high. I then moved out to 200 yrds. Wouldn't ya know it, I was still a shade to the left, about 0.3). My group measured 1.92," and 2" low, pretty good for a good ole boy.

Lessons learned: A small change at 100 makes a BIG change at 200.

Don't base a load on only a few groups. I should not have "assumed" I was directly over the bull at 100 bc of a single group.

All-in-all, I'm very pleased. I have a .308 cal hunting rifle, running 2870 fps, shooing ragged holes at 100 and just under 2" at 200yrds. I'm sure this round/rifle would do even better in the hands of a "real marksman." This load seems onlhy to be limited by me.

Thanks again.