I fired two five shot groups at 300 yards. One was 2 3/8" and the other was 2 11/16". Both were about 1" vertical dispersion. There was a slight 1 o'clock to 12 o'clock breeze. Anyone know what causes it?

I hate it when they "spring" to the left or right..

🌬

What rest are you using ?

Did you lose your marbles? Is this a rhetorical question?

I just might have a answer to this mystery
A friend wrote this elsewhere, and I have slightly modified it for the question at hand...When shooting at 300 yards with a centerfire weapon, integrating the differential of the function's parabolic natural log means that exponential growth in the ballistic coefficient still amounts to less change in the Coriolis factor impacting wind shift than imparted y the longitudinal tidal force on the perfect sphere on a frictionless plane before imparting the subdural hematoma via hydrostatic shock on the bullet changing horizontal impact at 300 yards.

xp,

Thanks. I think I got it. If I was firing east to west instead of south to north they would have been about 1" groups.

I hope it put a smile on your face

Don’t think I’ve ever seen a parabolic natural log. The ones I see tend to be pretty straight or bowed in the middle.

Regarding the wind. A 12 or 1 o’clock wind would be pretty straight on too. Wouldn’t think it would have much effect.

But math was never my strong point

I think you have it figured out...but you are still above that 1/4 MOA group...but that 1" group would keep you in the "X" ring
BTW-Thanks for starting this thread!

Its a great informative thread. If you are a democrap..

At 300 yrs that line about Coriolous is total BS. Generally horizontal stringing is wind gust or the shooter....

My post below was in total sarcasm/jest, and is intentionally and absolutely meaningless.
"When shooting at 300 yards with a centerfire weapon, integrating the differential of the function's parabolic natural log means that exponential growth in the ballistic coefficient still amounts to less change in the Coriolis factor impacting wind shift than imparted y the longitudinal tidal force on the perfect sphere on a frictionless plane before imparting the subdural hematoma via hydrostatic shock on the bullet changing horizontal impact at 300 yards."

Wow.

300 years is a long ways.

A lot of it is the shooter, even with a scope with poor parallax, it is still on the shooter. However parallax can be an issue. It could also be a rifle issue. Poor bedding or pressure on one side of the barrel etc. etc.. Someone also asked what kind of front rest or bags or bi-pod he's using, with no response from the op. He's likely on a fishing expedition. Also what you have here is a guy that has been telling us how good his scopes are, yet he can't figure out easy issues. Recently he has had issues with a high dollar March scope. He said he couldn't even hit the target and his buddy kept telling him he was shooting over it. There are some guys that can figure this schidt out and others that just don't get it. They never will..

I’m calling it now, thread of the year.

Check out the logs in Kansas, sometimes they get a little parabolic. Lots of wind out there!

All the trees here in central ks point north. Definitely will make parabolic logs some day.

This thread is hilarious

A wind from 11:00, 1:00, 7:00 or 5:00 is 30 degrees off so crosswind effect would be half that of the same wind from 3:00 or 9:00.

Biggest effect I've experienced on causing lateral (horizontal stringing) off the bench is not having the rifle fore-end centered in the front rest, causing intermittent horizontal stringing.

Ed

😀😀😀

What time of day did you shoot? If the sun was out with a slight breeze mirage would open up the group. If it's a known load your shooting I would lean toward you were getting a weather report instead of a load report! Other causes would be seating depth, rifle needs cleaned, scope giving up, your not a good shot, etc

Maybe the gravity wasn’t Continuously pulling the same during your shooting session, fluctuations can cause vertical strings.

While the parabolic natural log calculations have merit, a much larger effect on vertical dispersion is the vertical wonkiness factor or VWF. When it approaches infinity the rotational portion of projectile repeatability increases exponentially, and may have influenced the results observed by the shooter at 300 yards. To complicate matters, the VWF and HWF (horizontal wonkiness factor) interactionally inversely influence each other, forming the total tangential wonkiness factor, TTWF. When TTWF approaches 1.0000000 use extreme caution as point of impact could be almost anywhere, and the group size approaches infinity.

Another force may be in play here as well; the trigger spring twanger tension, TSTT. It can be influenced by any number of things such as the change in density, viscosity, shear force etc. of the lubrication in the mechanism, relative expansion/contraction in the steel, aluminum, plastic parts, and more. All of these are sensitive to temperature, pressure, dew point, phase of the moon, velocity of the trigger pull, and general wiggling around on the bench. A simple example of this is flicking a booger off your finger (the spring twanger) where the viscosity and stickiness can dictate success or failure to launch the projectile in a particular direction and hit the target in the intended location. Groups....forget it! Especially without a good rest.

The math involved in the calculations is expansive, and would have given Albert Einstein indigestion or worse. Where is Stephen Hawking when we need him most?

My math is VWF + HWF + TTWF + TSTT = 100% BS

Good One!

Horizontal is tuned out with seating depth during load development. Seat the bullet in .005 increments away from the lands until you see the load go horizontal and then you’ve went too far. If it’s factory ammo, nothing you can do without a barrel tuner. It can be trigger puller induced also which would be the first thing to try and rule out.

It may help to sacrifice a small animal, like a rabbit or a chicken, to the gods of horizontal dispersion. Works for me. I sacrifice hundreds of small animals a year.

^^^This!^^^

I had the same problem with a 7mmRM last year. Great groups vertically but pretty much two separate groups, separated horizontally. Anyway, somebody on some form said that adjusting the seating depth should correct it and it went from 1.5MOA to 0.5MOA.

Yes, air masses of differing temperatures seeking equilibrium. During the day, air above land heats up faster than air above water. Warm air above land expands and rises, and heavier, cooler air rushes in to take its place, creating wind. At night, the winds are reversed because air cools more rapidly over land than it does over water.

Yall are funny. Coriolis and 300 yard groups. 2 inches? Lol. Nut loose behind the trigger. 2 inch group at 300, I'm happy, lmao.

What Ernie and onebackcast said,I might add that environmental issues are a major variable in the group size as is the shooters ability to read such........

The shooter. You weren`t shooting the conditions, but just shooting.

Good example of Horizontal springing. Notice the wind direction.

On serious note. Is Vertical stringing is due to powder charge?

Mostly blamed on velocity variation, which can be due to several effects. Charge, cartridge neck issues, inconsistent OAL.

For once i think you might have nailed it Ernie. lol

It’s due to the powder charge creating an exit time that occurs when the barrel is moving violently

Barrel harmonics

Thanks.
So do you go up or down in charge?

https://www.24hourcampfire.com/ubbt...never-improved-upon-load-de#Post17925733

stringing can be caused by a bunch of factors, in my experience, wind and /or shooter form are the main causes.
Case in point, here is a 500 meter target with horizontal stringing that has nothing to do with the load or anything else but shooter form and /or wind calls.
It was shot prone with an iron sighted match rifle .
The Vbull is 1 MOA or about 5 inches, the 5 ring is 2 MOA or about 10 inches
Cat

Wiggling.

I look @ ES/SD for vertical stringing and track that down 1st. Recoiling your front sling swivel into your rest doesn't help either.

Man, you have been listening to Kamala way too long.

I would check and thoroughly clean the crown area and check that the rifle is properly bedded. Also you could change scopes and see if you get a similar result.

I was thinking the exact same thing. Whoda thunkit?

‘Course maybe this has something to do with it 💨

All kidding aside (and some of the above posts were pretty entertaining), if you can rule out wind, mirage, rest set up, table manners and scope problems and your load still wants to string out horizontally, your load isn't warm enough. Be careful but go a bit hotter.