Horizontal ??

[Flat Land Shooter]

I have come up with a couple of loads that have very little vertical, but more horizontal that I like and I'm pretty sure it wasn't the wind (tail on the flags almost straight down) or the guy on the trigger ( I've been shooting rimfire for 3 years ) .
My question is, do I work on the seating depth first or the neck tension?
6BR, 1-8 twist, 30 gr. varget, 80 gr. berger, just touching the lands, .002 neck tension.
Any help would be appreciated. I'm sure you figured out that this is my first custom barrel and my first shot at load development.
Thanks

 

[ebb]

How light is the trigger? Sometimes that can be the problem that causes horizonal if it is too heavy or rough.

 

[Flat Land Shooter]

The trigger is 6 -7 oz., just changed the barrel to 6 BR, didn't see this before.

 

[glo]

I'm going to assume you have new a match grade, air gauged, stress relived or stainless steel barrel. If not that's your problem. Chromoly barrels have memory like and elephant.

Unfortunately if you have a barrel that meets the above specs, it was the shooter. He/she needs to improve their breathing technic. How about the scope mounts?

 

[bheadboy]

horizontal is more often a problem of shooter, sorry about that, but check these

cheek presure variation,
trigger hand pressure on stock or tightnes of gripm
shoulder presure,
positon of but on shoulder
trigger finger positon changing on the trigger, more or less of finger into the trigger
position of eye in line with the scope, right left of center, head tilted etc.


Bob

 

[Erik Cortina]

Tune it out with seating depth.

 

[jo191145]

I agree with Eric. Horizontal is part of the tune just a little harder to diagnose whether it be wind, shooter, or tune (mostly seating depth)

A small excerpt from "Secrets of the Houston Warehouse"

Virgil said his practice was to seat the bullets so the engraving was half as long as the width of the lands. He noticed an interesting phenomenon with rifles that could really shoot: if the bullets were seated a little short and the powder charge was a bit on the light side, the groups formed vertically. As he seated the bullets farther out and increased the powder charge, the groups finally became horizontal. If he went still farther, the groups formed big globs. He said the trick is to find the midway point between vertical and horizontal. That point should be a small hole.

I stumbled upon this entertaining story early in my (learn to shoot rifle career)
This bit of information has stuck with me and served me well. I've found the seating adjustments described above to work irregardless of distance to the lands be it jammed or jumped. Find horizontal groups and back away from the lands in small increments. I personally do not mess with the powder charge until the horizontal is under control. I always run an Audette first so I'm either in or close to the node. Seating depth to form the group then slight tweaking on the charge to tighten things up.

And I should say,,,,, every once in a while you'll find a gun/load combo that reacts just the opposite ???

 

[Flat Land Shooter]

Maybe I started out wrong, but I only changed the charge and found two (29.8 & 30.0) that seem to work. The 29.8 group was like a clover leaf with five holes that over lapped, with center to center about the diameter of the bullet for vertical and horizontal. The 30.0 group had vertical at half the diameter of the bullet but the horizontal was over 5/8 inch. I shot these two back to back, wind was not an issue and I don't think it was me. Some of you indicate I should work with the seating depth, so I'll try that next.
Thanks for all the input!

 

[Erik Cortina]

Yes, play with seating depth next. Move bullet in .003" increments and you will be amazed.

 

[Flat Land Shooter]

Erik - you were right I was amazed at what a little change in seating depth will do. I loaded the 30.0 with four different seating depths, all just .003 apart. I now have a load that pulled the wide horizontal in to match the vertical at half a bullet diameter. I know thats what did it as there was a 10 - 12 mph wind from behind at a 45 left to right.

Thanks!

 

[Erik Cortina]

Yes, play with seating depth next. Move bullet in .003" increments and you will be amazed.

Erik - you were right I was amazed at what a little change in seating depth will do. I loaded the 30.0 with four different seating depths, all just .003 apart. I now have a load that pulled the wide horizontal in to match the vertical at half a bullet diameter. I know thats what did it as there was a 10 - 12 mph wind from behind at a 45 left to right.

Thanks!

I told you you would be! ;D

I'm glad I was able to help.