I've read here and on other sites and pubs that vertical stringing is minimized when chamber pressures are such that the bullet leaves the barrel at the top or bottom of the barrel travel during the harmonincs of the barrel when fired...hence the significance of ladder tests to find a starting point during load development. All makes sense.

But I've also read that minimizing horizontal stringing is a function of proper bullet seating depth. If this is true, then why is it true?

Tim

Most of my horizontal stringing has been due to optics issues like loose mounts. Vertical is typically bedding issues. Simple dispersion requires load tuning.

In my experience, stringing of any kind usually relates to something like a barrel rubbing on the stock.

When you pop off a round, you start a shock wave down your barrel. The shock wave travels faster (because it's in steel) than the bullet does. So when the bullet arrives at the muzzle, the muzzle is moving.

The motion of the barrel is probably usually elliptical. Whether it is or not, there will be places, like the end of the ellipse, where the barrel is moving very little. If your bullet exits at one of these nodes, your groups will tend to be smaller. That is because even with pretty uniform loads, the time it takes a bullet to transit the barrel varies slightly. If your bullet exits at a node, small changes in bullet transit time do not affect point of impact. If your bullet exits far from a node, small differences in transit time make a bigger difference in POI.



This, too.

The gun mount will make a big difference where the bullet hits the target. It requires the same mount to the shoulder and the same cheek weld. Both of these can cause horizontals. I know because it happened with me.

I'll be the first to admit that I sometimes get horrizontal stringing with my heavy kickers after I've had too much of them....I'll jerk the trigger etc. I shoot left handed and most of the time pull them off to the left...Now take the human error out of the equation and just focus on the mechanicals, a horizontal stringing issue is usually a result of uneven barrel contact or pressure on one side (the reason many suggest freefloating to accurize). Poor bedding can also cause horrizontal and vertical stringing. None of my rifles are left unbedded, so that is never an issue. However, I've seen it and fixed a few of my friends' rifles with issues...

Like with everything in the rifle game, there are no absolutes.

Horizontal and vertical can be the load, equipment, or the Loose Nut on the trigger.

Make sure the equipment is right, technique is good, then work on making the best Match Grade ammo you can.

Both can also be caused by a scope, too. Sometimes the elevation or windage spring(s) loosen up a little. Horizontal stringing can also be a parallax issue when the comb is a little too low for a good cheek weld: It will keep you from moving your head back and forth as much, but not up and down.

Always figured horizontal strings happened because the target moved. One day out in Cody it was blowin 50-60 mph. Dunno if they found the 4x8 OSB target boards to this day.

Been at Perry before in nationals when the wind was strong enough to snap some of the 2x4 target carrier uprights.

I was GLAD to keep all my rounds as scoreable hits offhand that day. Really glad. Wife did the same and I was really proud of her.

If you are referring to a solid rest, the mount may have a lot to do with it.Two of my shooting buddies, who shoot 2-3 times a week, have all had the same experience. If not paying partular attention, gun mounts are not consistent.

If the buttstock is either high or low, it will give you horizontals. The three of us are used to shooting very small groups and when we start seeing horizontals, we go back to the basics and watch our mounts. I've not had the experience with verticals, so have no opinion.

I had horizontal stringing in my 270 using RL22 and a 130gr TSX. I was determine to use this load as I hit 3,225fps, safely. To cure it, I tried 3 different brands of brass, several different primer makes, played with seating depth and powder charge weight, and even re-bedded the rifle, thinking the old bedding had deteriorated. No change, still had horizontal stringing.

My rifle just would not shoot this combination. I cured the stringing by using H4831SC and H4350, but I gave up a little speed.

go to 6mmbenchrest.com and search for "vertical stringing". It will list a series of reasons for vertical stringing.

Assuming the scope, mounts, and bedding are good?? Sometimes a lttle more powder will cure a little vertical. I have seen a load that was a little hot put one out of the group. Bullet seating depth will affect both vertical and horizontal as will neck tension.