vertical string

[Mark Daiute]

The load:

30.5 grains 4064 under 311299 sized to .308 in a cut-down Krag with a 23" barrel.

The results: 7 out of 10 shots touching each other at a range of 50 yards to form vertical string.

Symptom of?

I'm using 4064 because I have 9 pounds of it.

[Doc Highwall]

A front rest that is too hard causes the gun to jump during recoil, also resting the gun on the wrong spot on the rest can cause the same thing. If the front rest is not too hard try resting the forend of the gun either farther back towards the receiver or farther forward towards the muzzle. When you have the gun in the right spot it will not jump off the rest when you shoot and will be noticeable.

[Dutchman]

One of my Swede m/96 has a Harris bipod up at the lower sling band. One shooting session resulted in a really bad vertical spread. I sat there and wondered, scratching my head until it occurred to me that I'd been rocking up and down, pivoting the rifle on the bipod.

You notice Doc Highwall went right to this area as the cause and not the ammo or powder or time of day. Try using a rear sandbag and see what happens.

Dutch

[Larry Gibson]

Probably caused by incosistent powder position in the case. This can cause a high extreme spread in velocity which results many times in a vertical string. I would suggest a 1/2 - 3/4 gr dacron filler to keep the powder back against the primer for consistent ignition. You might want to drop back to 28 gr and work up again in 1/2 gr increments if you use the dacron filler.

Larry Gibson

[jimr]

Probably caused by incosistent powder position in the case. This can cause a high extreme spread in velocity which results many times in a vertical string. I would suggest a 1/2 - 3/4 gr dacron filler to keep the powder back against the primer for consistent ignition. You might want to drop back to 28 gr and work up again in 1/2 gr increments if you use the dacron filler.

Larry Gibson


the use of dacron helped control the stringing in my groups.

[Mark Daiute]

Thanks for the comments. In the final analysis it looks like BOTH my hold and powder positioning have been a factor. Dacron has helped, markedly, and when I have a consistent hold the groups are tight.

I'm still working on finding the best load but I am very close @ 30.0 grains of 4064 under my 311299 sized at .308.

Mark

[Mark Daiute]

Thanks for the comments. In the final analysis it looks like BOTH my hold and powder positioning have been a factor. Dacron has helped, markedly, and when I have a consistent hold the groups are tight.

I'm still working on finding the best load but I am very close @ 30.0 grains of 4064 under my 311299 sized at .308.

Mark