Poor accuracy at 300y, great at 400

[bultinkle]

No I doubt it., low sample size of some other variable is probably at play here

No one ever proves it and the people that try to reference positive compensation in Br rifles and act like those aren't also shooting insanely well at the shorter distance.

But if you think you're the one I think Bryan litz still has an active prize for anyone that can go to the applied ballistics mobile lab and prove it

 

[cajun]

So if I read this right
Your holding dead on to 300 then dialing for 400? According to Hornadys ballistics the 162 eldx 7 mag sighted 1.5" at 100 is 6.5" low at 300.

 

[sndmn11]

@Mr. Magoo where are you at in CO?

 

[Mr. Magoo]

I

No I doubt it., low sample size of some other variable is probably at play here

No one ever proves it and the people that try to reference positive compensation in Br rifles and act like those aren't also shooting insanely well at the shorter distance.

But if you think you're the one I think Bryan litz still has an active prize for anyone that can go to the applied ballistics mobile lab and prove it

Yeah, sample size here is key. Wish I had time for load development. Have a ditch to dig today.

I would definitley lie about such things just to get to go to brian litz's lab

 

[marksman1941]

I may have missed this, but have you done the test dialing at 300 instead of holding over? I know your goal is use holdovers at 300, but that would be a good method of testing whether it's a scope issue. I have found that dialing and shooting with the crosshair center tends to be more inherently reliable than doing holdover. I know time and components are a consideration, but I would really recommend going back out and dialing to 100, 200, 300, 400, and then dial back down and shoot the same ranges with holdover and see if you have deviation.

Theoretically speaking it should not matter assuming the gun is level every shot. BUT if you're slightly angling the rifle when you're making that 300 yard holdover shot, it could cause the impact to walk back and forth a bit. Now this could still happen with a dial, but it seems to me that it's easier to verify you're crosshairs are square when you're holding dead on the target. Does that make sense?

 

[Mr. Magoo]

So if I read this right
Your holding dead on to 300 then dialing for 400? According to Hornadys ballistics the 162 eldx 7 mag sighted 1.5" at 100 is 6.5" low at 300.

Hmm. I come up with about 2.5" low at 300 and 2.64" high at 150y. Not sure what we're doing different unless youre putting in a different zero. I'm zeroing at 262 yards because it gives me point blank range of 300 figuring 2.5" up or down from zero. 7800' elevation, 70 degrees.

Where I plan to mostly hunt, there are little meadows i can sit and watch where there is about a 300 yard window except for one where its about 500 to the far side. The smaller ones are interspersed with willows and trees where you may not get time to range or dial. This is the reason behind my madness.

 

[Mr. Magoo]

I may have missed this, but have you done the test dialing at 300 instead of holding over? I know your goal is use holdovers at 300, but that would be a good method of testing whether it's a scope issue. I have found that dialing and shooting with the crosshair center tends to be more inherently reliable than doing holdover. I know time and components are a consideration, but I would really recommend going back out and dialing to 100, 200, 300, 400, and then dial back down and shoot the same ranges with holdover and see if you have deviation.

Theoretically speaking it should not matter assuming the gun is level every shot. BUT if you're slightly angling the rifle when you're making that 300 yard holdover shot, it could cause the impact to walk back and forth a bit. Now this could still happen with a dial, but it seems to me that it's easier to verify you're crosshairs are square when you're holding dead on the target. Does that make sense?

Yep makes sense. In my case I'm holding dead on at 100, 200, and 300. Impact should be 2.5ish inches low at 300 (I could have made a mistake on that, very likely).

I'm zeroing at 262 yards. It only takes a little bit of difference in zero range according to the app to make a huge difference at 300.

Why I find it so easy to hit at 400 and 500 is the puzzling part.

 

[marksman1941]

Yep makes sense. In my case I'm holding dead on at 100, 200, and 300. Impact should be 2.5ish inches low at 300 (i could have made a mistake, on that, very likely).

I'm zeroing at 262 yards. It only takes a little but of difference in zero range according to the app to make a huge difference at 300.

Why I find it so easy to hit at 400 and 500 is the puzzling part.

That is a mystery…

 

[blvette75]

I may have missed this, but have you done the test dialing at 300 instead of holding over? I know your goal is use holdovers at 300, but that would be a good method of testing whether it's a scope issue. I have found that dialing and shooting with the crosshair center tends to be more inherently reliable than doing holdover. I know time and components are a consideration, but I would really recommend going back out and dialing to 100, 200, 300, 400, and then dial back down and shoot the same ranges with holdover and see if you have deviation.

Theoretically speaking it should not matter assuming the gun is level every shot. BUT if you're slightly angling the rifle when you're making that 300 yard holdover shot, it could cause the impact to walk back and forth a bit. Now this could still happen with a dial, but it seems to me that it's easier to verify you're crosshairs are square when you're holding dead on the target. Does that make sense?

Well back in the day when I had a range where I could zero at 400 yards, I also did 100 and 200 yards checks. I use the fancy Christmas tree reticles now, and now use the holdovers for hunting instead of dialing up and down. When I start to see variance that does not seem reasonable I do go back to the center cross hairs on the zero as you suggest. I have levels on all of my rifles now and that seemed to eliminate some cant issues.

 

[marksman1941]

Well back in the day when I had a range where I could zero at 400 yards, I also did 100 and 200 yards checks. I use the fancy Christmas tree reticles now, and now use the holdovers for hunting instead of dialing up and down. When I start to see variance that does not seem reasonable I do go back to the center cross hairs on the zero as you suggest. I have levels on all of my rifles now and that seemed to eliminate some cant issues.

A scope lever helps a ton. Unless you do what I did my first try and install it juuuust a hair out of plumb. That caused so many issues until I realized what was going on.

 

[Ben]

I had a Benchrest/varmint gun that did the same thing. Mediocre groups at 300 and then tighter (in moa) at 500. Like never explain it.

 

[tribb]

Y

I had a Benchrest/varmint gun that did the same thing. Mediocre groups at 300 and then tighter (in moa) at 500. Like never explain it.

May be we need some one (I know I do) to post about how to properly level the rifle and then properly install and level the scope. I'm new at the game of shooting beyond 350 yards. Hint Hint ????

 

[Joefrazell]

TL;DR
Do bullets have areas in thier flight path where they destabilize, then re-stabilize and become more accurate?

I have not personally seen this to such a degree in any of my shooting before.

Details:
I've been working on getting a browning a-bolt 7 mag, 1 in 9 twist, sighted in and trajectory mapped. Has a vortex strike eagle 3-18x scope that I pulled off my 308 and has proven rock solid on that.

Heres where it gets wierd. Rifle shoots a hair over moa at 100, 1.5 moa at 200, 2+moa at 300, and .5 to .75 moa at 400. Winds were 5mph and less.

My current life keeps me from having enough time to reload these days, so I'm using factory hornady 162 gr eld-x ammo. Chrono is on perma-loan so I don't know the exact speed of this stuff. Just using hornady data for now.

Not only is it shooting much worse at 300, but it is also shooing much lower at that range than it should. At all other ranges I tested is it right on the money elevation wise when using the hornady app and I was able to get multiple first shot, cold bore hits at 400 and 500 while practicing.

I played around with a bunch of different scenarios assuming my data was off but in no scenario I could come up with does it work out being that far off at 300 and right on everywhere else.

Do bullets have areas of instability that big

This would have to repeat itself over and over multiple times to mean it's actually valid. Or you'd have to shoot through see through targets at 300 and see what happens at 400

 

[Mr. Magoo]

@Mr. Magoo where are you at in CO?

SLV.