vertical stringing ?

[fisherman983]

what is the typical root cause and what are the standard steps to remedy this problem?

have a custom rifle that shoots really well and after shooting a group at 550 yards, my vertical string was pretty horrible, close to 8"

 

[Barrelnut]

Can be caused by the ammo, usually bad extreme spread or standard deviation.
What's you chronograph say?

Can also be the rifle weight distribution or some small errors in shooting form. Small things can really start to show up at 600 yards.

Here's the best article I've read on vertical stringing. Helped me a lot.
CURES for VERTICAL STRINGING

 

[fisherman983]

I don't remember what the SD was, but ES was 11 at the time I shot through the chronograph. I am using Remington brass so that may be the case.

 

[ShtrRdy]

When it happens to me, I usually have inconsistent shoulder pressure, or I've got some different tension in my upper body - shoulders, diaphragm, stomach, ....

 

[Waynard]

Is there any pressure under the barrel near the end of the stock?

 

[fisherman983]

Barrel is free floated...McMillan a3 stock and jewel trigger

 

[Grumulkin]

what is the typical root cause and what are the standard steps to remedy this problem?

have a custom rifle that shoots really well and after shooting a group at 550 yards, my vertical string was pretty horrible, close to 8"

I assume that when you say it shoots "really well" you mean at shorter ranges; to know how much shorter would be useful. Also, what is "really well"? If it is true that groups at say 100 yards or 200 yards are very good, you can probably eliminate a scope problem or technique as a cause. The most likely cause would be velocity variation.

When you say 8" I presume you mean vertical spread. How much was horizontal spread?

 

[LoneTraveler]

Did you log your shots? Did the shots jump up and down in the string? If they jump around in the string it may have been shooting form or even light on the range changing. If it started and walked up or down with each shot it may be bore not centered in barrel and heat is causing the barrel to warp and change POI. Or the barrel may be collecting jacket in one grove and causing a walk of the POI if not lapped perfectly even in smoothness. It will be a hunt. Good Luck in finding the cause and a cure.

 

[rcoody]

8" at 550 yards? how much long range shooting have you done? not bad really if you are just starting out.

again what was the total group size.

I always feel like vertical is mostly ammo and can be the gun and horizontal is mostly me.

This can be a difficult process but if you break it down and eat the apple one bite at a time you can solve this dilemma.

I would go ammo first and try to get the best reloads you can create. you will probably do load development for some time. Trying different bullets, powders and loads. Get some good practice during this period.

next would be the rifle. Make sure it is free floated. vertical stringing is an obvious sign of barrel pressure.

Last would be you. You probably like me need the most work. Try to do the same thing every time. the way you hold the gun. cheek pressure. trigger pull it is crazy.

that is why you see those 1000 yrd benchrester free recoiling their guns. about the only thing touching the gun is their trigger finger and it is about a 2 oz trigger.

 

[704]

rear support sinking IE: rear bag during recoil Hold it firm
Stock has a low heel causing downward torque causing muzzle flip
bipod not loaded forward causing skip

many things but these can be controlled by the shooter.

 

[tbrice23]

Mechanical issues can be paramount.
I recently modified a magazine in my M111 LRH 300 win mag to allow 190 vld to be used as a repeater.
The modified mag was binding up against the bolt. When I switched to the factory mag my problems went away. All shots at 200 yards.

 

[fisherman983]

is it possible that my barrel is still breaking in? there is only 110 rounds down the tube

 

[Barrelnut]

is it possible that my barrel is still breaking in? there is only 110 rounds down the tube

I think to barrel could be considered broken in at this point. Earlier in the thread you mentioned changing brass. If you shot one brand of brass at short range and another at long range without a new load workup for the brass used at longe range, this could be a big issue.

You need a baseline so you can see what is causing the problem. I would start back at 100 yards, use the same load and brass, then move that load and brass to long range and see the results. Keep your shooting for constant while shooting the groups.

Let us see the results.

 

[fisherman983]

I haven't changed brass, just was saying that the brass I am using is remmington brand. I will load some more, and shoot again and take pictures.

I was at the range yesterday but it was way too windy to attempt a group at 550, which is as far as my range goes, but did shoot another group at 100 and wasn't very happy. i was so angry i didn't bother taking pictures or bringing the target home with me.

I am fairly certain it is not me, my shooting ability or my ability to reload ammo. I had 2 other rifles with me yesterday to shoot loads for. a semi custom 338 rum, and a tikka 270 win.

the rum produced a group with 3 shots measuring .15, into 1 large hole.
and the 270 had one 3 shot group measuring just a tad under 1/4 moa.