Alright, I've been trying to solve this one for quite some time. At this point I think it may just be misalignment between the action and the barrel, but I really have no idea.
Before answering, make sure to really go over what I've done here, as the simple fixes that come to mind might not do the trick.
So, here goes. The rig is a stock 700P, scope is a Mark 4 3.5-10X, base is a Badger, rings have been both Badger and Leupold.
The problem I'm experiencing is a bizarre shift in POI at 300 yards after setting my 100 yard zero. What I'll do is get my 100 yard zero down perfectly, then take a target out to 300. Almost invariably, my groups will shoot about 1.5-2" to the right. It seems to be about the same offset (~0.5 MOA) at longer distances too (I've tried at 600y).
The first thing that will obviously come to your mind will be tracking. Well, at this point there's just no way that's the issue. How am I so sure? Three reasons:
1. I've mounted and leveled this thing countless times, using five different methods-
A) The beginner way- with the Weaver level-level-level
B) The feeler gauge method
C) By placing a level on the scope base, getting it level, and then aligning the reticle with a plumb line
D) Using a high quality boresighter with a beam splitter to get a cross sectional line with which to align the reticle
E) Using this nifty little tool from EXD:
http://www.brownells.com/.aspx/pid=6097/product/EXD_ENGINEERING_VERTICAL_RETICLE_INSTRUMENT
Which allows you to align your scope perfectly to the bore and both to gravity using a plumb line.
Every single method produced these same results. I've become a minor expert on scope mounting, I will say that
2. I've done countless tracking tests once it's mounted. Here is just one example at 100y-
First three shot group was shot using the 100y zero at the lower-most cross. Second three shot group was fired after I cranked the elevation up 20 MOA- you'll see it at the top. I don't how much better it could track!
3. Still confused, I decided to really take tracking out of the equation. I hung up some 300y targets and, while leaving the scope at its 100y zero and not touching a thing, I fired off groups while aiming right at the target. Elevation was, as expected, about 14" lower than the bull. Windage was off as always- about 1.5-2" to the right. Remember, this was without using any tracking.
So for all of these reasons, I've come to pretty much entirely rule out the scope itself, any tracking issues with it, or rotational misalignment with respect to the base/bore.
I tried swapping the rings, going from Badgers to Leupold. Didn't help much.
I keep resisting what might be the inevitable- that without a trued and aligned barrel/action, I may be S. out of luck. But, that's why I decided to post here.
A couple of other points-
1. When I *do* adjust windage at 300 to get it spot on (usually 0.5 left), and I try back at 100, it's then indeed too far to the left.
2. It might be shooter error, I'll admit, but I keep thinking that if this were the case, I'd see the same issues at 100 yards. 0.5 MOA might not be much, but when you're shooting at tiny dots, that's a pretty big miss. Still, I have one last test to determine if this is the culprit- I'm going to shoot weak side, mirroring everything I do. If the pattern persists at 300 and in the same direction, it's probably not me.
I unfortunately don't have a lot of shooters near me with similar equipment, so I can't easily put another quality scope on here or move my scope to a good rifle, otherwise I'd try that.
Alright all, have at it- what are your thoughts? What can I try to get to the bottom of this?
Thanks so much for your help.
Before answering, make sure to really go over what I've done here, as the simple fixes that come to mind might not do the trick.
So, here goes. The rig is a stock 700P, scope is a Mark 4 3.5-10X, base is a Badger, rings have been both Badger and Leupold.
The problem I'm experiencing is a bizarre shift in POI at 300 yards after setting my 100 yard zero. What I'll do is get my 100 yard zero down perfectly, then take a target out to 300. Almost invariably, my groups will shoot about 1.5-2" to the right. It seems to be about the same offset (~0.5 MOA) at longer distances too (I've tried at 600y).
The first thing that will obviously come to your mind will be tracking. Well, at this point there's just no way that's the issue. How am I so sure? Three reasons:
1. I've mounted and leveled this thing countless times, using five different methods-
A) The beginner way- with the Weaver level-level-level
B) The feeler gauge method
C) By placing a level on the scope base, getting it level, and then aligning the reticle with a plumb line
D) Using a high quality boresighter with a beam splitter to get a cross sectional line with which to align the reticle
E) Using this nifty little tool from EXD:
http://www.brownells.com/.aspx/pid=6097/product/EXD_ENGINEERING_VERTICAL_RETICLE_INSTRUMENT
Which allows you to align your scope perfectly to the bore and both to gravity using a plumb line.
Every single method produced these same results. I've become a minor expert on scope mounting, I will say that
2. I've done countless tracking tests once it's mounted. Here is just one example at 100y-
First three shot group was shot using the 100y zero at the lower-most cross. Second three shot group was fired after I cranked the elevation up 20 MOA- you'll see it at the top. I don't how much better it could track!
3. Still confused, I decided to really take tracking out of the equation. I hung up some 300y targets and, while leaving the scope at its 100y zero and not touching a thing, I fired off groups while aiming right at the target. Elevation was, as expected, about 14" lower than the bull. Windage was off as always- about 1.5-2" to the right. Remember, this was without using any tracking.
So for all of these reasons, I've come to pretty much entirely rule out the scope itself, any tracking issues with it, or rotational misalignment with respect to the base/bore.
I tried swapping the rings, going from Badgers to Leupold. Didn't help much.
I keep resisting what might be the inevitable- that without a trued and aligned barrel/action, I may be S. out of luck. But, that's why I decided to post here.
A couple of other points-
1. When I *do* adjust windage at 300 to get it spot on (usually 0.5 left), and I try back at 100, it's then indeed too far to the left.
2. It might be shooter error, I'll admit, but I keep thinking that if this were the case, I'd see the same issues at 100 yards. 0.5 MOA might not be much, but when you're shooting at tiny dots, that's a pretty big miss. Still, I have one last test to determine if this is the culprit- I'm going to shoot weak side, mirroring everything I do. If the pattern persists at 300 and in the same direction, it's probably not me.
I unfortunately don't have a lot of shooters near me with similar equipment, so I can't easily put another quality scope on here or move my scope to a good rifle, otherwise I'd try that.
Alright all, have at it- what are your thoughts? What can I try to get to the bottom of this?
Thanks so much for your help.
)
