The "Horizonal Tune"

jackie schmidt

jackie schmidt

New member
How many times have we stood by the Wailing Wall, looking at targets, many with straight accross "catepillars", (or in ten shot groups, "tomato worms"), and hear shooters say, "well, at least it's in tune"

Or is it?? I have long suspected that just as there is a bad verticle tune, there is also an equally bad horizonal tune. In other words, the Rifle might be shooting flat, but is so darned wind sensitive that any little nuance at all in the condition results in huge horizonal spreads on the target. By "nuances", I mean changes that mere mortals can not seemto detect.

Many times I have tuned the verticle out of my Rifle with the tuner, only to have shots go left or right in conditions that simply do not, (seem to), warrant that much movement. At the 200 HV last Sunday afternoon, I started out with about .600 of verticle in some really heavy conditions. I prided myself in that I was able to read the cross wind that well. When I upped the charge and got the Rifle shooting in what I thought was a great tune, I noticed that It suddenly developed 1 inch of horizonal when before, with the verticle in the tune, it had about a bullet holes worth. I was just lucky in that I held correctly a couple of times.

I suppose the ideal is, (in heavy conditions), to find a tune that just shoots nice round holes, with just enough verticle to cancel out the horizonal tendancy. You might not ever nail that sub .300 group at 200,(or the .150 at 100), but the thing says in the hunt with globs that are in the .450-.650 range at 200 when everybody else is shooting perfectly flat 1.250's.

I am probably just thinking out loud, trying to ignore the reality that about 10 more points on my IQ would be a great help.:D.......jackie
 
Jackie,

One of the hardest things for my hard head to remember is something that Dwight told me a few years ago. The conversation went like this.

Friday before the supershoot in '06 I believe. I took delivery of a new gun. I left the next day for Ohio and when I got there and set up, I first decided to walk around and talk to a few people before I started tuning. The wind was really blowing hard. I walked up to Dwight S. and Gene B. who where loading together and we talked for a couple of minutes when I mentioned to Dwight "I sure wish the wind would slow down so I can tune in my rifle". Dwight said "why". I told him "Well, I don't think I can see what's going on in this stuff". Of course his comment was "You'd better cause it's going to be like this all week". Now, he could see the blank terror in my face and commenced to tell me how to tune in the wind.

Dwight told me to take three different loads to the line, set down, foul the barrel and shoot them.....without looking at the flags!!!!! Now, I didn't know if he was BS'ing me or what but the look of disbelief in my face caused him to expound further. Dwight said, the key is not how small a group you can shoot, it's to keep the damage at minimun when you miss a change.....which is not if it will happen, but when it happens. He told me, there are things that happen at this (and other) ranges that you can not see in the flags so you better make sure the drift don't burn you to bad. What he was telling me to do is to tune for wind drift rather than vertical. He also stated, doing this won't help you shoot screamers or small groups in a trigger pulling contest but he said they are a lot further inbetween than shooting in the wind.

What he was trying to relay to me was, it is ok to tune the vertical out in the rifle when tuning at home and shoot small groups but just use that as a starting place when warming up a day or two before the shoot at the range and shoot in different winds and tune out the drift.

Now if I can just get that to stick in my head all the time...I might do better.

I have talked to more than a few top shooters who told me that they fine tune their guns by "not paying attention to the flags". What I have done lately is, I will find two different bullets that shoot the same or close in a barrel in good conditions, then shoot them in 180 degree switches and see which one drifts less.....it's a real eye opener and the same bullet don't always win.....

One thing that just popped in my mind, when Bill Calfee tunes a gun, he doesn't use wind flags either.

Hovis
 
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Jackie,
I think I proved to myself yesterday at the range shooting my 6ppc that there is horizontal tune as well. I was trying to develope a load with the new XBR powder. Wind was a bit switchy but nothing really bad. I shoot mostly 65 Bruno or Gentner BT's. Two loads have for the last year or so be kind of "go to" loads. 28.5-29.0 of 133 and 30.0-30.4 of BMark. Most everything I shot with XBR was globs, But when I went to the 29.0 of 133 I had about 1/2 bullet of verticle and about 1 to 1.25" of horizontal. Temp was about 80+ and 20% humidity. I know I didn't miss the wind that much. Then switched to the 30.0 BMark and right back to a smallish round group. Now how do we take out the horizontal? Barrel is a Kreiger 13.5, with your .269 chamber.

Donald

Donald
 
Jackie, I credit Daryl Loker with enlightening me about the importance of neck tension and seating depth. Several years ago Daryl said to me,

"Tune the horizontal out with neck tension and seating depth and then tune the vertical out with the load."

My expereinces in the tunnel have proven Daryl is certainly right. He has found that in most cases, the best place to seat the bullet is just barely in contact with the lands but not "sticking" in the lands.

As far as neck tension is concerned, I believe it can only be determined by feel. I use what most would refer to as medium neck tension. Invariably when I seat the bullets on 'jam' I get one to two bullet holes of horizontal; in the tunnel! :eek: :rolleyes:

With medium neck tension, the bullets are normally forced into the lands about .020 from just touching. Usually, backing the bullets off 'jam' about .010 to .015 eliminates horizontal. Once horizontal has been eliminated, neck tension and seating depth should not be changed; do all remaining tuning with either the load or a tuner.

Come out and shoot with me in the tunnel when you can.

Later

Gene Beggs
 
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Years ago I suspected there was such a thing as a horizontal tune, but since it was always outdoors I figured it was the wind. In the mid 90's I was able to shoot indoors for about 2 years and was able to satisfy myself that it indeed existed as I could repeat it. The clue to when you are on it, is that it is DEAD flat. I mean essentialy 0 vertical and it is about 3/8 moa wide and will alternate shots side to side in varying degrees. The good news is a change of .1 gr down load will bring it in to a round hole around .1 or less of vertical.
 
A few years ago at a local group match...

... we had some very strong crosswind on the first day. We shot LV 100 in the morning and LV 200 in the afternoon.

After the match the guy following me on my bench showed me his last 200-yard target and it was nearly two inches straight across. His comment to me was "at least the gun is tuned because the group (his words, not mine) was dead flat."

We looked at the target right above it which was a .480 or so that was as tall as it was wide. All I could say was that "my gun must not be tuned as well as yours."

I can tell you that when things are blowing across the range (wind, wind flags, trees, witches on bicycles, etc) it may behoove you to tune a little upwards vertical into you group. (Shots dropping out the bottom are usually indicative of a too light of a load.) The group may look ugly. But, an ugly four beats a beautifully flat inch-plus straight line at 200 yards. A very well-respected, long-time competitor (again, I won't drop names or give his resume) uses the reference of putting a half bullet-hole at 100 and a bullet-hole or so at 200. That will cut down on the occurance of the "train wrecks".
 
I am sure I am about to show my ignorance but what is wrong with a tune that has a little bit of wind drift and then learning to dance with the wind????? I ran across this same issue at the Shamrock with a good friend of mine when we were discussing tune and shooting his rifle.

Matthew S Keller
 
Matt,

The reason you won't be able to dope the wind as well, is because the bullets will drift inconsistantly, just like your horizontal being out. Unpredictable.

Hovis
 
Wind drift is one thing...

... as long as the bullet goes where it looks like the condition should take it. I guess what the focus of this discussion is more related to cutting conditions versus being overly sensitive to other certain range conditions.

I can honestly say that I have shot extremely large groups (and aggregates) in every way possible, and have been lucky enough to have shot some decently small agg.'s at other times. Due to the experience of the first statement above, I feel qualified to make the following statements.

What I has witnessed is that some tunes are more sensitive to certain conditions than others. A tune with a little bit of vertical in it seems to cut down the SENSITIVITY to a cross wind. And vice versa, that same tune may go wildly large in a tail wind. I have also seen tunes that shoot great and fight conditions in one direction (say, left-to-right) that will go large in a right-to-left. Then there are times that the gun is not in tune with any of the prevaling range conditions and it just seems that nothing works (on that given day).

I typically see this phenomenon when the gun is tuned to the very edge of being "super tuned" and are just a hair's breadth from having the load "blow up". You know what I'm talking about. The gun shoots a group below what you would expect the range conditions to give you. And then the very next group is a "whopper".

This is not just a PPC phenomenon. Two weekends ago I shot my .30 BR in a NBRSA score match at WWCCA. The day before I "tuned" the rifle at 200-yards and it looked pretty good. Unfortunately, I didn't work the gun in the practice session to see what it would do in varying range conditions. (Instead, I got lazy and kept working with the load and seating depth until I shot one small group and then went and got a pizza with my shooting buddies. I call this a "recipe for future disaster".)

Then the next day during the match we had some "switchy" conditions and the gun looked like it was broke for the first three targets. I dropped two points and didn't really scare the dot in various conditions on those targets. I was sitting at 148-2X's thrugh those three.

Then on the sighter box of the fourth target I noticed that the gun shot consistently in the left-to-right, but only the left-to-right. It would go "stupid" on the right-to-left or let-offs. I waited for the left-to-right on the last two targets and finished at 248-12 X's.

I'm a little slow on the uptake, but it appears that with that day's tune that the gun would shoot great in a very specific condition. We all most likely have seen days when the gun wouldn't hit a bull in the arse. And other days when if the flags lined up in a certain way, we could do no wrong and the gun literally shoots by itself. Perhaps in that latter situation we had the gun tuned for a specific condition and we looked for that condition and it worked. (Thus being "in concert" with our equipment.) My contention is that one doesn't shoot teen agg.'s or high X-count if the gun isn't tuned for the prevailing condition and we look for that "tuned condition" to shoot in.

So, I guess the discussion is about "sensitivity" in certain range conditions versus tuning to "cut conditions" in another.
 
That was an excellent post Joe, very descriptive and educational.

Thank you,

George
 
This gets tough

Jerry H said:
Years ago I suspected there was such a thing as a horizontal tune, but since it was always outdoors I figured it was the wind. In the mid 90's I was able to shoot indoors for about 2 years and was able to satisfy myself that it indeed existed as I could repeat it. The clue to when you are on it, is that it is DEAD flat. I mean essentialy 0 vertical and it is about 3/8 moa wide and will alternate shots side to side in varying degrees. The good news is a change of .1 gr down load will bring it in to a round hole around .1 or less of vertical.
Click to expand...


for those who believe charges as much as .3 off makes no difference. :)
 
I don't know if experience in a totally different environment has any validity here, particularly as I'm not talking about achieving anything like the degree of accuracy needed for BR, but back in the days when I shot target rifle (Palma Stateside), we once operated with a set of rules that required local factory loads to be used in team competitions while you could use handloads for individual shooting. In any case, both were limited to the .308W case & 2155 Sierra projectiles.

Obviously the trick was to get the factory fodder shooting as well as possible in your rifle, then build up a handload that would match it so you only had one set of variables to worry about. Aussie NRAA factory stuff doesn't shoot too badly at all, but we tuned it to maximise the performance in each barrel by inching the foresight back & forward until the best grouping was achieved. Essentially, the foresight was a behind the muzzle tuner.

We had one guy who did a lot of tuning for the less skilled & the indolent & I occasionally shot beside him off the benches when load testing. One thing that seemed to consistently occur while tuning with this quality of load was that as the tuner was adjusted, a group would string vertical, group round, tighten, loosen then string horizontal as he moved the foresight thru a "sweet spot".

Now, I'll emphasise here again. We're talking about factory loads here that might be expected to hold something around 1 MOA plus or minus out at 1000 yards, and maybe down to ½ MOAish at 300-600 most of the time, but there seems to be a similarity nevertheless.
 
one thing i might add

when most say wind sensitive or horizontal grouping i can certainly relate to what it apprears like,but i think what most are seeing is velocity variance creating unpredictable wind holds or dispersion in a wind that is readable.in my case a 30 fps es works out to .250 of horizontal wind read errors in a very light push and just gets worse with the stronger push .somtimes when you tweek the powder charge you can actually change the velocity spreads as well leveling them out and seeing less horizontal spreads.i have heard that 40 fps extreme spreads are the norm in 100-300 benchrest for just dumping powder and using low bc bullets isnt helping much but i would think the guys weighing their powder dont see this issue as much. tim in tx
 
Shortly after I bought a press, powder, bullets etc I stumbled on the story "Secrets of the Houston Warehouse" on the web.

Theres a sentence or two in there that describes how Virgil would tune his gun. I had no idea if this entire story was fiction or not but I embellished those few sentences in my memory.

It works most of the time. No one can convince me horizontal is not part of the tune.
 
I wonder....

jo191145 said:
No one can convince me horizontal is not part of the tune.
Click to expand...

A question here, in what direction does the muzzle vibrate? We think of it as just oscillating up and down. Does it oscillate in a circular or some other non liner pattern? The year I shot tuners all through the season I could never get any "horizontal" into or out of the barrel deflection.

Bill Myers, a well known rimfire gunsmith, attached a "read and hold" electronic indicator on a barrel of a rail gun. It was on a fixture that could be rotated to record muzzle deflection in a 360 degree arc span. His data showed that a barrel vibrates vertically but in a 1:00 O'Clock to 7:00 O'Clock pattern. But his indicator only records on 0.0001" movements and there may be other muzzle movements his indicator didn't record.

On the horizontal there is the issue of how soon does the bullet stabilize on its axis. I think it is generally agreed that the wobbly bullet, before it "goes to sleep", is more deflected by crosswinds than a on-axis stabilized bullet. Wind mostly effects the horizontal so if the wobbly thing is actually a factor then bullet on-axis stabilization would show up mostly in the horizontal direction.
 
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This is mere speculation, though, I would think Bullet yaw in the barrel
would be the best place to create horizontal in a group. This is product
of non concentric ammo , Being a mechanical issue,
it would be related to dies, seating depth, neck tension etc.Not all
bullets are spinning on their centerline axis as they emerge from the muzzle.
Those that are, make the transition from the bore to the atmosphere
much faster, those that are not, lose course often to conditions.
 
Bob Kingsbury said:
This is mere speculation, though, I would think Bullet yaw in the barrel
would be the best place to create horizontal in a group. This is product
of non concentric ammo , Being a mechanical issue,
it would be related to dies, seating depth, neck tension etc.Not all
bullets are spinning on their centerline axis as they emerge from the muzzle.
Those that are, make the transition from the bore to the atmosphere
much faster, those that are not, lose course often to conditions.
Click to expand...
Bob, wouldn't in-bore yaw be random, not just horizontal? I think I see where you are coming from, the wobbly bullet thing, but???? Dunno!
 
Jerry

Let me go on record. I have no science to back up my contention. Lets call it a superstition on my part;) One I'll doggedly stick by until I can disprove it myself.
I'm just a newbie playing with accurate cartridges with no formal education on the subject. As such I sometimes develop theories on patterns I see happening on the target that sometimes do not agree with conventional wisdom. Right or wrong these theories seem to work for me. Eventually:D
 
Jerry Sharrett

Yes, I would believe it is random, almost has to be. But as we
look at targets, generally some assumptions are common. That is
wide shots are more easily accepted as a missed flag, where as Verticle
is tune . So we focus more on the verticle. Some of the verticle may
also be in barrel yaw which never seems to disappear.
 
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