How does .8" at 100 yds become 2.5" at 200 yds?

[Slamfire]

Many possibles. Mirage comes to mind. I would consider that very normal. My 50 bmg will consistantly make better goups @ 200 yd then 100 yd.

I agree with mirage. Mirage moves the image around, but not the target! Seen that time and again on ranges where the mirage is like a soup. And then wind. Boy have I learned about wind since shooting small bore prone. Wind is chaotic, wind velocity and direction often changes several times from the firing point down to the target. There can be invisible "dust devils" and wind currents doing barrel rolls between you and the target. Those "dust devils" actually move, without dust or grass, you won't see it.

You want to shoot when the wind is laminar and moving consistently. The best smallbore prone shooters shoot in the predominant wind conditions. And a good small bore prone match has more flags than a 4th of July parade!

 

[Kaldor]

ES/SD which leads to vertical stringing becoming more pronounced as distance increases all other things being equal. Horizontal stringing is generally the shooter.

A bullet does not magically become more stable or accurate as range increases. Bryan Litz has disproven that about a 100 times over.

 

[ms6852]

Picture sight alignment plays a big role from 100 yards to 200 yards. Your cheek weld may not be as precise as you might have thought and if you believe that is not the problem then check and see if the parallax on your scope is set to 200 yards. Also know that a load that is shot at one hundred yards may not be good at 200 yards. It is for this reason that when I zero my rifle, it is done with loads that group sub-moa or moa at 200 yards not one hundred. Your one hundred yard group is real good but seems that it could benefit from a better trigger control or breathing or maybe both. Thanks for posting pictures.

 

[Catpop]

I always told my customers “if you want to shoot at x yards, then practice at x yards!”
The target you are using may be part of the problem. Great target at 100 yards-I use them too. But when I start stretching out the distance, I find the crosshairs sometimes start blotting out the center. At longer distances I like the Outers “4 block” targets.
Example (please disregard holes) this target center allows you to see the crosshairs centered between the 4 blocks.
Jmho

 

[Lee Q. Loader]

Thanks everyone for taking the time to help me out.
I'm going to take all your suggestions to heart. First thing I will do is work on my shooting techique and get some better 200 yard targets.
I'm not going to change my load. I think it's a good load. I'll shoot a bunch more at 200 yards and decide for sure.
This is what makes reloading and shooting such a fascination for me!

 

[AJC1]

Thanks everyone for taking the time to help me out.
I'm going to take all your suggestions to heart. First thing I will do I work on my shooting techique and get some better 200 yard targets.
I'm not going to change my load. I think it's a good load. I'll shoot a bunch more at 200 yards and decide for sure.
This is what makes reloading and shooting such a fascination for me!

The very best accuracy is adjusted for the conditions of the moment and the current condition of the rifle. No reason to go that far unless you must. Have fun focusing on the parts that bring you the most joy.

 

[Varminterror]

Rate of rifling
Bullet design
Stability

All you can do is shoot and see.

I had a 7 mag 150gr Nosler shot 4" @100 yards. 4" @200 yards, 4" @300 yards and 5" @400 yards.

It just took a bit to stabilize. Most shots from my stand were 300 - 400 yards. I was sighted in at 350. Was very surprised when I shot 200 and 100.

Bryan Litz and the Applied Ballistics crew have a check for you…

You’re not the first to claim it, but will be the first to prove it.

 

[jmorris]

I think one could spend a lifetime counting the ways .8 becomes 2.5 over 100 yards and providing data to support each way.

 

[Seedy Character]

Checks in the mail?

I'll hold my breath.

 

[AJC1]

I think one could spend a lifetime counting the ways .8 becomes 2.5 over 100 yards and providing data to support each way.

I just default to I screwed up.... honesty is the first step of recovery.

 

[rdnktrkr]

I've been concentrating on putting the stock in the same place and my cheek the same place on the stock and that has helped me increase my consistency. My last time out I even tried resting my thumb on the trigger guard and pinching the trigger but I think that doesn't allow consistent shoulder pressure.

There are a lot of very accurate shooters here and they have given you some great pointers. I enjoy shooting with other shooters that way if you run into a problem maybe they can spot it while your at the range and you can let them shoot your rifle to see if it is repeatable.

Wait till you try 600yrds, I went to the Talladega CMP, I was shooting sub moa at 100, 200 and 300yrds, then when I went to 600yrds and was all over the place, I wasn't having this problem with other rifles holding the x and 10 ring with them so I'm thinking that bullet, powder or combination of those contributed to my problem. Other shooters also had problems at 600yrds with that rifle. 223 69gr sp and H335 powder just below max, I've been using this load for a while this was just the first time I tried anything over 300yrds.

 

[jmorris]

I just default to I screwed up.... honesty is the first step of recovery.

Yeah, that’s an easy one to prove.

 

[N555]

Looks like when I try to shoot in the wind.

 

[Demi-human]

Looks like the 9 o’clock three changed to an 11 o’clock 12.

Looks like when I try to shoot in the wind.

That’s why I try not to do it…
I only look like I know what I’m doing when it’s calm out!

 

[Col. Harrumph]

All the above, plus parallax.

 

[Fishtales]

Four of your 200 yard shots are in the same location as all six of the 100 yard shots and almost as tight. Excellent shooting in my opinion. Two of the 200 yard shots are "flyers". My guesses are heated barrel, if you shot 12 shots in a row, or shooter error (sorry-most of us have had that problem at one time or another (or, in my case, quite a number of more times). Stick with your loads and shoot some more. Hope it turns out well.

 

[film495]

possible the wind at the targets is not consistent. further out might have a different variable between 100-200 yards.

 

[longdayjake]

I see vertical stringing. This could be due to a couple of things. The most common one I see is barrel heating up. I often shoot a 3" circle at 550 yards. I can consistently hit it with my hunting rifle at least the first four or five shots. After that, once the barrel heats up it will change my POI a bit and then I have to start guessing. If you're shooting grendel the odds are it's semi auto which will heat up pretty quick. Also, if you're shooting semi auto the last round in the mag will have a different POI.

 

[BreechFace]

. Also, if you're shooting semi auto the last round in the mag will have a different POI.

Why’s that Jake?