A scoped .308 Kimber 84M that will shoot a five shot “bug hole” at 100 yards with hand loads. Move to 200 yards, rifle will shoot almost a perfect circle group that opens up to 3”. The center of the circular group is the center X of a 3” sticker dot. I am thinking that my older, cataract eyes are the cause of the group opening and maybe even the circular shape. If you think it is not me and maybe the rifle, what do you think is causing the group to open and circle the center X? Thank you.
Rifle Grouping Question
- Thread starter Steve S.
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243winxb
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Edit- Set the parallax at 200 yds. Adjust eye piece focus. Wear corrective lens, if in use, that provide 20-20 vision.
Fine tune the scopes parallax, till the focus is clear at 200. The yardage markings on the scope are not always correct. A Higher power scope may help. Do use wind flags.
3" @ 300, not bad at all.
Fine tune the scopes parallax, till the focus is clear at 200. The yardage markings on the scope are not always correct. A Higher power scope may help. Do use wind flags.
3" @ 300, not bad at all.
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Parallax and focus aren't the same thing. Parallax is when you don't get your eye directly in line behind the scopes crosshairs and are looking through the scope at an angle. At most that will cause bullet impact to be off around 1/4" at 200 yards vs getting your eye directly behind the scope.
Most scopes are set to be parallax free at 150 yards so I doubt this is the issue. That means that at 150 yards it doesn't matter if you're not directly behind the crosshairs, but at closer, or longer ranges it does. But it ain't nearly as much as many think.
It is important that you focus the scope for the range you plan to shoot. But if you're focused at 100 yards then 200 shouldn't be much if any out of focus. It is when you start shooting inside 100 yards that this becomes more critical. many scopes focused at 50 yards will be out of focus at 100, and vice versa. But if zeroed at 100 then longer ranges are rarely a problem. Any adjustment needed at longer ranges will be very minor, but this could be at least part of the issue.
I'm thinking you're right about your vision and cataracts. Scope quality matters a lot. Many of the less expensive, scopes just aren't as clear and sharp as more expensive scopes. Younger guys with better vision may not notice, but as I've gotten older I've found that quality matters with optics.
Most scopes are set to be parallax free at 150 yards so I doubt this is the issue. That means that at 150 yards it doesn't matter if you're not directly behind the crosshairs, but at closer, or longer ranges it does. But it ain't nearly as much as many think.
It is important that you focus the scope for the range you plan to shoot. But if you're focused at 100 yards then 200 shouldn't be much if any out of focus. It is when you start shooting inside 100 yards that this becomes more critical. many scopes focused at 50 yards will be out of focus at 100, and vice versa. But if zeroed at 100 then longer ranges are rarely a problem. Any adjustment needed at longer ranges will be very minor, but this could be at least part of the issue.
I'm thinking you're right about your vision and cataracts. Scope quality matters a lot. Many of the less expensive, scopes just aren't as clear and sharp as more expensive scopes. Younger guys with better vision may not notice, but as I've gotten older I've found that quality matters with optics.
DocRock
member
Are not the Kimber 84s somewhat notorious for this? A 5.5 lbs rifle in .308 Win. The question is what happens in the first shot at 100 200 and 300 yards and then the first 2 shots. If the first shot is consistently sub MOA to POA, and the second shot is within say 2" out to 300 yards, I would not be upset. It's a carry much, shoot little rifle, not a target rifle. My expectations for the 84M would be repeatable cold shots within 2" of POA zeroed at 300 yards and second shots within 3". After that, I would expect groups to open up. It's a light gun with a sporter contour barrel, so those numbers seem reasonable to me.
It is probably a combination of my eye blurs and the nature if the super light 84M model. My eyes simply will not focus very well at 200 yards and the pencil barrel of 84M (although I do let it cool between shots) does heat very quickly - it is definitely not a range or target rifle. With that said, that might be as good as it gets but, a 3” circle group at 200 yards is still a very dead deer - good enough for that purpose.
JFrank
Member
I think the rifle isnt tuned quite as well as you thought, re tune at 200 yards would be my approach.
Aletheia
Member
If you're using a scope there should be no difference in your ability to focus at different distances because you don't focus at the distance. A scope creates an image at a certain point no matter how far away the object is, and you should focus that image so that it is clear to your eyes. It will be clear at all distances if you do it right. Parallax is a different optical property entirely, and, although it could be a reason for the larger groups, it is not likely the cause. I actually do not have a very likely cause for the larger group at 200 yards, but not being able to focus your eyes at 200 yard targets is not the cause.
Captcurt
Member
I would chalk it up to pilot error, but it is a Kimber. This is a light hunting rifle. I wouldn't worry about group size. i would want to know where the first bullet goes out of a cold barrel.
Varminterror
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Twice as far away requires a target and a POA reference twice as large, or twice as much magnification to produce the same reticle picture.
There is nothing which can happen to a bullet from a supersonic high powered rifle cartridge between 100 and 200 yards which would allow 5 bullets to be stacked at 100 (assuming this essentially attests to be sub-half MOA), but spread to 3” by 200yards - 1.5moa. It IS, however, exceptionally common for shooters to fail to maintain consistency in their POA hold as they move farther and farther out, as they’ll make the mistake of shooting the same size target and same POA reference rather than using targets which offer the same subtension. It’s also common that shooters will perceive the extended range as more difficult, so they make it so.
There is nothing which can happen to a bullet from a supersonic high powered rifle cartridge between 100 and 200 yards which would allow 5 bullets to be stacked at 100 (assuming this essentially attests to be sub-half MOA), but spread to 3” by 200yards - 1.5moa. It IS, however, exceptionally common for shooters to fail to maintain consistency in their POA hold as they move farther and farther out, as they’ll make the mistake of shooting the same size target and same POA reference rather than using targets which offer the same subtension. It’s also common that shooters will perceive the extended range as more difficult, so they make it so.
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