What causes this???

[lefty315]

So riddle me this.....

You have a rifle that consistently delivers 5/8 inch groups, and sometimes smaller, at 100 yards off the bench. You move the target to 200 yards and on the absolute best day all you can muster is maybe 2 inches and sometimes much worse. You pull back to 100 yards....5/8ths again.

 

[Ridgerunner665]

Parallax
Reticle covering more of the target
Inconsistent cheek weld (induces parallax error)

And the human factor... That is heartbeats and breathing.

 

[lefty315]

Not that I'm arguing with you and I get everything you're saying but I have other rifles that I can maintain tight groups out to 300 yards. Just not this one. On the very same day I can take a 300 WSM and hold 5 shots within 1.5 inches at 200 yards with relative ease.

I guess my question really should be what causes this if you can take the human factor out of it?

 

[Ridgerunner665]

The other things I mentioned above... I'd be looking at my scope... Checking parallax.

 

[rick smith]

It could be that your rifle doesn't like that bullet. Friend has a custom 30/06 that shoots 1/2 " at 100yds with his normal set-up. Changed bullets for an Elk hunt 1/2-3/4" at 100yds. 3-4 inches at 200yds and at 300yds it was hard to keep them all on a 12" square of paper. A switch to a different bullet solved the problem. Could be a twist problem and the bullet is not stable, scope parallax, pressure from the stock or any number of other problems. A change of powder may help. Rick.

 

[lefty315]

I've thought about the bullet, but would it shoot great groups at 100 then fall apart by 200? It's a7mm 140 grain AccuBond leaving the muzzle in the upper 2900 fps. Again I understand all the possible things a shooter can do wrong to make a group go to pieces at longer ranges, I'm just trying to figure out gun/bullet wise what would cause it to happen. I have a couple of rifles that actually hold a better group at 200 yards than 100 and know that a bullet may stabilize and settle in at a little more distance. Is it possible for a bullet to de-stabilize inbetween 100 and 200?

 

[JD338]

I'm thinking optics. It could also be the rest that is being used.
What scope do you have?

JD338

 

[Bruce Mc]

I read an article some time back that addressed bullet stability and in the article it was claimed that a bullet has several points where it could become unstable. It had to do with center of gravity of the bullet and the center of force of the bullet. The points of instability were at several different velocity thresholds, one being around 2500 fps and the other when a bullet becomes subsonic.

But I'm with everyone else, I think you might have an optics issue. I have a Leupold Vari-XII that was on my 7mm rem mag. I just couldn't get really small groups consistently. I got a newer VX2 and now I get those groups consistently.

 

[lefty315]

Scope is a Leupold VX 3. 2.5x8. I'm going to try a different rest, eve though that's the same one I use with everything else. I've got some Nosler Partitions I'm also going to try. I know sometimes a gun just doesn't care for a boat tail bullet. I'm only going to try one thing at a time though, so it may take me a bit to figure it out.

 

[wildgene]

...have you adjusted the focus w/ the objective bell lately??? I noticed my 7 wasn't shooting like it used to, scope had been on it for 10yrs. w/o adjustment, eyes got older. Just enough difference to make me start chasing the bull @ 200yds., not really enough to look "fuzzy". I'd start there...

 

[lefty315]

I've had to do that over the last couple of years with my scopes. I don't think it my eyes, I think all of my scopes are faulty!!!! I'm not sure if I've done it with that scope or not yet. How bad has it affected your longer range targets?

 

[wildgene]

I've had to do that over the last couple of years with my scopes. I don't think it my eyes, I think all of my scopes are faulty!!!! I'm not sure if I've done it with that scope or not yet. How bad has it affected your longer range targets?

...hasn't really been a problem since I realized what was happening & check my scopes once or twice a yr., but I've gone to higher power scopes on my big rifles, & I've got rid of everything that had a "Fast Focus" objective. Those nice, sticky rubber rings like to grab & turn when ever they touch anything, like getting slipped into a case, or being carried on a sling, & end up not where they're supposed to be when you bring up the rifle...

 

[ScreaminEagle]

I'd say that your load isn't in the ideal accuracy node. Have you shot it through a chrony? What was your ES? Also neck tension may be an issue.
Steve

 

[Vince]

I'd say that your load isn't in the ideal accuracy node. Have you shot it through a chrony? What was your ES? Also neck tension may be an issue.
Steve

Yup.
More to check.

Sent from my SGH-M919 using Tapatalk

 

[OU812]

So riddle me this.....

You have a rifle that consistently delivers 5/8 inch groups, and sometimes smaller, at 100 yards off the bench. You move the target to 200 yards and on the absolute best day all you can muster is maybe 2 inches and sometimes much worse. You pull back to 100 yards....5/8ths again.

I've seen the exact same issue with a rifle I once owned. MY 338 Lapua would shoot tiny groups at 100 yards with a 250 Partition but any farther out it was a pattern rather than a group. Take it back to 100 yards and tiny groups once again. Talked with Rick S about it and he recommended changing bullets. I did so and never had the issue again with that rifle. Just my .02

 

[lefty315]

I played around with where I position the gun on my rest. That had some affect. I started to work up a load with a 150 Partition and even threw a few out at 200 yards. They didn't look too bad. I was talking to a friend who does a lot of shooting and reloading. He talked about how tight my action screws were. I think I may borrow his torque wrench and play around with that a bit before I do much more with different bullets.

I did notice on my last four shots that if I pulled the gun fairly snug into my shoulder and made sure I had plenty of downward cheek pressure the group became more respectable. I don't do a ton of shooting but I've never had to work a gun that hard before to maintain consistency at longer ranges. Weird.....

 

[Ridgerunner665]

I played around with where I position the gun on my rest. That had some affect. I started to work up a load with a 150 Partition and even threw a few out at 200 yards. They didn't look too bad. I was talking to a friend who does a lot of shooting and reloading. He talked about how tight my action screws were. I think I may borrow his torque wrench and play around with that a bit before I do much more with different bullets.

I did notice on my last four shots that if I pulled the gun fairly snug into my shoulder and made sure I had plenty of downward cheek pressure the group became more respectable. I don't do a ton of shooting but I've never had to work a gun that hard before to maintain consistency at longer ranges. Weird.....

Thats beginning to sound like this might be one of those really lightweight rifles...is it?

If it is...form and fundamentals are EXTREMELY important.

Also....what you've said there would support my first suggestion too...parallax.

 

[lefty315]

Winchester model 70 featherweight. I do notice too that the stock is fairly thin with no raised cheek piece.

 

[Ridgerunner665]

Winchester model 70 featherweight. I do notice too that the stock is fairly thin with no raised cheek piece.

Featherweights are not light...my wifes 270 is about right in my opinion, not too light, not too heavy...perfect for a carrying rifle.

If I were you...I'd concentrate on consistent cheek weld...maybe look at other options for scope mounting...a tad higher or lower.

I think your troubles are stemming from the way you're getting behind the optic...not saying you're doing anything wrong...just that either the way the scope is mounted isn't fitting you or the scope has excessive parallax (it happens, even to good scopes)

Try this...close your eyes, bring the rifle to your shoulder and settle in with a comfy cheek weld, open your eyes but don't move your cheek weld...based on what you see, which way does the scope need to move to be where you need it?

Cheek welds vary I reckon...but a good one will be pretty snug.