Vertical Stringing

[Forestar]

Murphy and/or Others:

What causes vertical stringing? I know inconsistent ignition and inconsistent velocities can do it, but I don't think that's the problem. Any other causes and solutions?

Thank you.

P/S. I'm shooting a Sako 75 in 270 WSM with a Leupold VXIII 4.5 - 14.

 

[Bill S.]

Previous discussion may help. http://forums.outdoorsdirectory.com/showthread.php?t=1314

 

[Snowwolfe]

A good deal of vertical stringing is related to improper bedding and/or how the butt of the rifle fits against your shoulder. Wearing different clothes to the range (light shirt versus heavy jacket) can cause the butt to seat differently against your shoulder. If you are wearing the same clothing I would have the bedding checked.

 

[kenaifoto]

Breathing can also cause vertical stringing. Also relaxing your wrist or tightening your wrist can contribute to vertical stringing. but I would also check your bedding screws.

 

[Forestar]

Thank you

Thank you

Lots of good info here and in that archived thread.

Thank you.

 

[Murphy]

Stringing along...

Stringing along...

Forestar,

In general when a rifle strings shots vertically it is caused by poor bedding. That is, the rifle doesn't fit into the stock well, it moves in the stock upon firing, or the mounting screws are loose. This loose stock could make large round groups. This of course assumes that scopes or sighting equipment is well mounted, and not moving. Also barrel heating up during the string can walk shots up and down. Light barrels need longer between shots.

The problem often is, however, shooting technique on the part of the shooter, and not the rifle. When sand bagging a rifle in, the rifle recoils when fired and this recoil signature must be the same with each shot. Your grip on the rifle matters a lot. The shoulder position and pressure, the stock weld between cheek and stock, and the grip location and pressure on the froend, all must be consistant. Also, a rifle with a heavy barrel will lay on the bags more consistantly, will jump less and will reposition after the shot better than a light barrel. Light barreled rifles are more difficult to shoot accurately from the bench.
There are other minor things which effect the consistancy. Such as the density of the material in the bags, (sand is best) and the material that the bags are made from. (leather is best) Also the technique that is best for a heavy barrel rifle will not be best for the light sporter barrel. Or the heavy recoiler may require a different technique than a small caliber. I can't tell you what is best just be aware that these things can affect the shot.

I let the forend lay freely on the front bag and donot touch the forend. I pull the rifle to my shoulder, back at the grip with the left hand and loosely grip with the shooting hand. I know this works for me. There are other effective techniques. But what the rest are saying here is valid. Rifle butt placement, stock weld and grip, bagging and bedding, will all make or break a shot.

Now to your question, it is certainly true that ammunition can cause vertical stringing of shots and this is generally related to wide variations in velocity. When I handload for a caliber I don't accuracy test until I have SD numbers down to single digits because in my experience this matters significantly when searching for the accurate shot or the smallest group. Also I have learned that I am almost always the weakest link in the chain, when it comes to making the shot.

We get this down to a science and breath control and shooting between heartbeats becomes second nature to a good shooter. Part of this bonding with the rifle.

 

[Mike Echo]

Beween heartbeats?? Crimminee... At my age I am just waiting for the next one to come along!
Mike