Seating Depth / Horizontal Stringing During Load Development

[squirrelsnpr]

I thought I recalled seeing a post which brought up the idea that during load development, vertical was a "cured" by +/- powder and horizontal was "cured" with seating depth. This seems to be an accurate statement as long as your charge is yielding consistent FPS. Could someone comment on the horizontal portion of this statement?

The reason I ask, is because I am working up a load for a 20-222, and got a group which has almost 0 vertical stinging, but about 1 MOA of horizontal stinging at 200 yards. All other charges = approximately 1-1.5 MOA. This is the beginning of my load development, so its looking pretty good.

On an semi related issue, my CED M2 is acting up / having issues picking up the 20 cal bullets. Any suggestions?
Thanks,
Mitch

 

[ThunderDownUnder]

Mitch, If you dont have any vertical stringing, (you quote zero vertical) then the horizontal must be simply wind or a hold problem. When shooting groups its normal to have a circular spread on the target with components of both vertical and horizontal displacement.

If you have zero vertical dispersion I would say your load developement is done and you need to read the wind a little better or perhaps fine tune your hold. The fact is that you must be awful close to having a good load so dont give up on it yet without a bit more shooting to see how it goes!

Ian

 

[squirrelsnpr]

I understand there is always operator error, but I dont think its all me. The reason why I say this is b/c I was getting loads which had very little horizontal and much more vertical stringing. I'm going to play with seating depth next range visit. Hopefully, I'll be able to nail down a good load.

 

[bp1965]

Remember seeing an article in the daily bulletin some months back about a group that shot in an abandon warehouse that addressed this issue but I could not find it now.
I'm sure someone on here knows far more than I on the subject.

 

[bp1965]

I googled and found it,(Secrets of the houston warehouse)hope this helps.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.

 

[gary0529]

Mitch,
Just a thought on the chrono not picking up the 20's.
Have you tried to blacken them with a Sharpie?
It might just help cut the "shiny" factor enough for the sensors to pick up.


Gary

 

[TonyR]

I have observed the horizontal stringing myself. Tony Boyer talks about vertical versus horizontal stringing in his recent book and does not always pick the load with the least vertical. Not to say that operator error and wind changes couldn't be a factor as well. They often are for me.

 

[drumcorpschamp]

I was doing some load development last evening at the range using two different bullets.

Bullet number one showed two nodes during the shooting where the holes were horizontal with an almost imperceptible amount of vertical. Those loads happened to have the most consistent velocities.

Bullet number two showed the groups in classic fashion where they started at about 3/4" round and went to one round hole then back up to about 3/4" round.

It was a calm evening with virtually no felt breeze to influence the bullets. I obviously have more work to do with the first bullet and seating depth testing is going to be my first try.

Jerry

 

[BoydAllen]

I believe that Mr. Boyer has said that tune that has no vertical can result in hypersensitivity to cross wind, producing horizontal stringing, and for that reason, he tunes for a half bullet hole of vertical at 100 yd. and a full bullet at 200yd. He has also mentioned that if the day is heating up, and your last group was a dot, that for the next match, you should drop your load, because of the extreme likelihood of having a shot pop way out of the group. Using felt wind as a measure of what is happening down range is not a reliable method. Wilbur Harris (who owns and runs Benchrest Central) once wrote words to the effect that it is amazing how the mere act of putting out a few wind flags always seems to make the wind start blowing. More than one person has observed that the best tune for a tunnel, where the temperature is constant, and there really is no wind, may not be the best tune for shooting outdoors. I think that this might also apply to warehouses. One thing that you should also take into consideration is that a fellow who is a shooter of known talent (OK I forget who) once wrote that although he had the privilege of shooting in the Houston warehouse on more than one occasion, that he never saw the extreme accuracy that was reported as being common at that facility. Sometimes stories get better with the telling. In group competition, it is the shooter with the smallest aggregate that wins. Having the smallest group may get you a record, and/or a prize, but it won't win the 2 or three gun, or even a yardage.

 

[drumcorpschamp]

I could have been more clear about the breeze......My poor man's wind flags (caution tape on wire frames at 30 yds. and 60 yds.) showed virtually no movement either. What a great evening to test loads!

Jerry