Vertical stringing

[Lead Pot]

Incosistant blowtubing will also give you a vertical string.

Kurt

[Todd Birch]

My long range rifle coach in the military (Lee-Enfield #4 .303 and FN C-1 FAL 7.62mm) had another reason for vertical stringing.....

This applies to a post type front sight and a six o'clock hold on a bulls-eye target, so it may not be applicable to a centre hold on a metallic silhouette.

If your zero was done on a cloudy or overcast day, chances are you allowed for a little more space between the top of the post and the bottom of the target than you will under bright, sunny conditions.
Then the tendency is to snuggle that sight a little closer to the bottom of the target because we see it so clearly and rounds hit higher.

Todd

[Stan Koslow]

Todd is on to it. It's been mine as I know many others knowledge that in secluded light there is a tendancy to 'dig in' when using a front post. It is how the eye works and defines the spacial relationship. One cloud can make a big difference. Another strange affect is the rising and setting of the sun. If your groups are going with the direction of the sun you may know why. A secondary factor to the setting of the sun is usually the lower temps as well as the light which affect BP, I believe a little more than smokeless.

Back in the early 90's I believe, I shot the state and terriotorial matches out here in Fresno. During my stick aggregrate it started at the beggining and toward the darkest period of a total or near total lunar eclipse. It went still, shadowless and was just damn spooky. My string started at X , then ten and walked into the 8 ring at about 10 o'clock. I was a possible shooter and could not for the life of me figure it out. I had to much time and confidence. I looked (spotted)down the line and soon noticed that the other twenty targets or so were doing the exact same thing. They were all stringing for the most part. I knew everyone had to be pulling their hair out but you did not hear a whisper. I took a chance and a little (a lot) of kentucky and blew the last one back as an X. That shot was like betting the pot on a couple of dueces. That was the strangest condition I have ever seen and until then felt confident about any condition I would have to encounter.

Now here is the good part. Hold on to your saddle on this one. I spoke to this issue with some real pointy heads. Here is what I got back. The gravity of and upon the earth had a slight change during this time and a projectile has not the same force placed upon it. and thus the rising string the deeper the eclipse got [less gravity]. The rotation of the projectile and speed of rotation becomes more relevant and depending upon the direction of the rifling would have an affect (Right twist & Left twist) The changing light (darker) is not only by a diminished affect but the Kelvin Temp goes sky high. ( possibly around 12000) deep shadow means blue light out of the spectrum that our brain reconizes but still can see. Thats why we wear yellow glasses to counter it ,as blue light also reduces contrast to our eyes. Ever look into a Flouro lit office from the outside and for the first second it looks blue-green then starts looking white? Thus your perception is just that, a perception. That's the neat thing about this sport, when you think you got the book read, someone comes along and adds a new page.. Shooting is a deteroriating sport, the less you shoot, the more you deteroriate.

[Todd Birch]

....then when we take into consideration the phases of the moon in conjunction with the coreolis effect, we really open a can of worms.....

However, if you are left handed and suffer from cross-domination of your master eye, there is utterly no hope for you.

Whatever happened to the good ol' days when if a bullet strayed, you got slapped in the back of the head and were told you pulled the shot?

Where's my BB gun and sling shot? This ain't fun no more.

Todd

[IronSight]

Hot dam, I always blamed the phase of the moon for my MOA load suddenly and mysteriously shooting shotgun patterns..and to think i might be right all along!
I exclusively use an aperature front sight to somewhat combat these celestial phenomenas and also because my eyes have problems focusing on front posts.

[ffffgdave@yahoo.com]

also theres headwind and tailwind.. im not as good as you guys are on this but some other things to condsider.. if youve got a light barrel -barrel jump can get in there.. primer seat pressure can cause velocity differences.. as mentioned earlier case lenght needs to be trimmed each time so crimp is the same if your crimping. if your close the the rifling but not touching this can caouse more/ less pressure.if you dont want to touch back off bullet a little more.. i think most touch rifling with a little pressure... of course most of these cause more torque from the rifling and wont give clean verticle stringing.. my guess is sighting problems or tail- headwind or barrel heating.. let gun cool adequitly, watch your wind, and hold onto barrel just behind front rest to see it still strings.. just blabering .. as i said i dont know as much about this as you guys.. almost forgot bullet weight is a classic caouse of lead ball verticle stringing.. your not using first cast bullets are you?? get mould up to temp before using bullets or weigh bullets.. good luck dave..

[ffffgdave@yahoo.com]

i got my muzzeloader notes out and dutch shultz has this to say about verticle stringing.. if the bullets impact one high, one low, up and down inconsistently its from pressure.. if the bullets string one after the other further off target each shot in the same direcrion its the sun heating the barrel or the barrel heating up . good bedding should let the barrel expand out and not put pressure up.. but the sun will raise havoc curling the barrel.. maybe pressur on barrel would string up and sun heat would string down i dont know.. another sighting phenom is with a rounded top curve on the top of the post with the sun up and behind.. a portion of the top of the post will glare and the shooter will pick differnt parts of the glare to use for eleveation.. good luck dave..

[IronSight]

ffffdave,
Once again, i relearned something i forgot about BP shooting. One of my rifles(my 1st) has a relatively light barrel 15/16" across the flats. Now that i remember and this was years ago, it was plagued with vertical stringing on hot sunny days. Between rounds, i kept it out of the direct sunlight and if practical tried to keep the bore pointing into the wind in an effort to cool down the barrel evenly. Even went so far as to construct supports out of heavy guage baling wire to create a 'cooling tent' using the rifle case for ranges with no shade. As i recall this along with lube improvements must of helped because i went on to concentrate on other accuracy problems.

When i used to compete with muzzleloaders, i also had glare problems with the front post. Painting the post with flat black paint and a heavy dose of sight black on top of the paint cured the problem.. for me anyhow.

[RichBratlee]

AAAAARRRRRGH --ok guys wow! Thanks for all the info read somethings I had forgotten over the years and learned some others---and that is why this is such a great forum--the amount of info and the average intelligence is outstanding!!!-- It looks like it was the loose nut behind the trigger for about 80% and the other 20% was a combo of untrimmed cases (smackin' the back of my own head) AND trying a taper crimp at the same time--Iknow Iknow--only change one thing at a time--but I just forgot that I hadn't trimmed this particular lot of brass --and yes the range in length from 2.102 all the way out to 2.109---so go ahead --please someone---and beat me about the head and shoulders so that the phrase and action of"CHeck your field/reloading notes prior to doing ANYTHING" sinks in again!!

Thanks again guys!!

Rich

[Outrider]

Oh come on Rich....I like Stan's explanation a lot better!
Outrider

[RichBratlee]

Yeah me too but amongst us I will own up but to an outsider--UH UH!!!--Allegan huh--know a Steve or Cliff Larson by any chance--Steve shoots a lot of CAS and is my cousin and Cliff is his Dad--Just curious!

Rich