How to shoot the dead calms

Gene Beggs said:
This calm condition/big group scenario has puzzled shooters for many years and it was only after I began shooting in the tunnel that I finally realized what I believe causes the problem. Wake turbulence!

My approach to anything is always influenced by a lifelong love of flying. You would be amazed at how much flying and shooting have in common.

Picture this. You arrive at the airport early in the morning and there is not a leaf moving. You climb into your little single engine airplane and taxi out for departure. The tower clears you for takeoff and adds, "Caution wake turbulence; departed DC-9 two minutes ago. You pour the coal to all 100 horses and begin your takeoff roll.

After lift off, everything is going great and the air is perfectly smooth when suddenly the little airplane pitches and rolls violently as if it flew into a storm. And that's exactly what has happened; it flew into the wake of the departed DC-9. Had there been a little crosswind, the wake would have been drifted downwind and out of the departure path. Do you suppose the same thing happens to our bullets when we shoot in a dead calm? :eek:

If there is no movement of the air mass, the wake of preceeding bullets remains in the flight path creating a rough ride for those that follow.

Later,

Gene Beggs
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This phenomenon could have also certainly been the culprit. It makes sense. How long do you think the wakes would remain in the path of incoming bullets?
 
goodgrouper said:
This phenomenon could have also certainly been the culprit. It makes sense. How long do you think the wakes would remain in the path of incoming bullets?
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Many years ago, when I was a kid, Whamo made a toy pistol and rifle. These shot "vortex" rings of air. We would put smoke or talcum powder in the diaphragm chamber so the "smoke" rings would be visible. It would take what seemed like up to a minute for this vortex to cross a 30 ft room. But when it got to the other side it could still knock down a house of cards. I'm thinking that the bullet vortex is doing the same thing.
 
HovisKM said:
Vibe...very smart I must say. Now you know what the laser system on the M1 Abrams does besides range distance. The information from the laser feeds, enemy speed, enemy direction, enemy distance, wind velocity and direction to the fire control computer which also inputs data from the on board GPS and corelates with other systems for the M1's own speed, direction and altitude. It doesn't have to have all the information to come up with a firing solution but the more info...the better the accuracy. These systems have been in place a long time.

Hovis
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The M1A1's computer used to use a turret mounted crosswind sensor, a turret traverse rate tachometer, vehicle speed, and a vehicle cant sensor in addition to the range info provided by the laser to come up with a ballistic solution....it sounds like they've added some other laser info plus GPS to the mix. They were amazingly accurate back then; I'm sure they're even more so now. I can remember nulling out the drift on the old "stab" systems.....It seemed so advanced then just to be able to fire on the move.

-Dave-:)
 
Your right Dave. I originally worked on some of the laser range finders when they were first on the tanks and they were basic compared to now. I wasn't familiar with some of the current system unitl I was at Anniston Army Depot and oversaw some of the rebuild as an ordnance officer. I don't know the specifics but a lot of the orignial system is still in play...almost like a verification/backup. The turret tachometer. If I remember right, they had the highest rate of failure of components in the firing solution but was primairly fixed during the refit's and change of the turret rings. The main cause was both rings were made out of the same material and hardness and galled real bad but before they would lock up, the tolerances would open until they got sloppy and then destroyed the sensors I believe. And I forgot about the cant sensors, this was a direct desendant from the turret mechanisms on the battleships from WWII.

They were advance for their time but the newer systems are spoiling the kids, oh...did you know about air conditioning?? I would tell you about the distances of recorded hits now in pratice but you would more likely believe me if I told you I had a Rem 700 BDL 270win that would shoot 1/4" all day long...

Hovis
 
Dead conditions:

As Wilbur said maybe 1 out of 3 you will end up ok, No wind means the bullet does not have a path that wind provides. The mirage is boiling straight up, left , and right at the same time. Don't play the odds if you are smart. Patience and a little wind is the key.



Lester
 
Lester is exactly right...

... as his shooting resume can attest.

I have also seen that in dead calm, especially with cool, heavy air like we get here in the North that heat coming off the barrel will cause the shots to drop due to the sight picture rising.

When that type of condition is present, I like to put an old target (preferably a small group, if I can find one) wrapped around the front of my scope and taped to the top of the barrel at the muzzle end. (This is a patented Joe Krupa performance enhancing component.) I have experimented in dead calm with this as compared to the standard mirage strip shields (which I call "advertising bands" because I feel that they are useless in a dead calm). When there is a lot of wind blowing across the barrel as it heats up during the firing, I believe that there is no need for a mirage shield at all because the heated air is being removed continually.

But, in the dead calm, I like to see something moving downrange, maybe a little wind or at least some mirage running in one direction on the target or mirage boards. When this occurs, I like to shoot five shots as fast as I can, and pray a lot.
 
Good Answers

As you can see by the responces you have recieved, shooting in a dead calm, such as often is found in the very first match of the morning, can be a real nightmare.

There have been times when I have nailed great groups in teseconditions, and times when the group looks like a catepillar crawling straight upthe target.

To shoot these condirions, you Rifle probably has to be in an IMPECCABLE tune. Ay Rachels Glenn this past week end, on Sat Morning, we had the very conditions you are asking about for the first match on at least the first two relays, (200 yards). I can tell you that, even though we were shooting Rail Guns, the groups for the majority were not that good. I shot a .329, and by all accounts, it should have been a .129.In fact,if you go to the results, and look at the groups shot in that dead calm, you can see that there was onl one sub .300 group shot in that dead calm. And that was a pretty good bunch of Unlimited shooters.

I would much rather shoot in just a little wind, something I can see. My flags are VERY sensitive, and if they aren't showing anything, then there just isn't much going on.

I did an experiment a few years ago with my Rail Gun. It was at the old Lake Houston Gun Club. We would have mornings there on the left side that could be described as "tunnel condition".

One particular morning, when it appeared that nothing was going on, I noticed that every flag was turned 90 degrees. Over a long period of time, every flag would ever so slowly completly switch to the other direction, and just stay there. I decide e something.

With the flags all pointing to green, (left to right), but with no tail movement or daisy movement, I carefully shot a 100 yard group. It was probably about a .120 or so. I then waited for what seemed tobe an etenity, and the flags slowly all turned to the orange, or a direct reversal. I waited untill all movement ceased, and no tail or daisy movement could be detected. I then carefully shot another group.

It was pretty close to the same size, but the entire group was moved on the target darned near a bullet holes worth.

It never hung again so I could repeat it, but that sure got my attention.

I think I agree with Joe, and the others. Get the Rifle warmed up, concentrate on your technique........


and pray........jackie
 
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Shooting a dead calm

There are two options;

1. Don't shoot, wait for some movement.

2. Very, very carefully

PLD
 
calm day shooting from what i've experienced is much more challenging than it looks. i had a practice day a few weeks back that the morning was dead calm. i shoot f-class at 600 yrds and am use to the boiling rolling mirage you can get being so close the ground. well i had shot 4 rounds and all were touching on the target when the next 2 went right and the next 3 went left. the conditions hadn't changed and i couldn't account for the flyer's at all. then my spotter asked me if my scope picture went out of focus on any of the shots. i told him i thought i was imaging it he told me that the spotting scope did the same. there was no visible mirage even at 40x power. so later after thinking about it and a lot of talking all we could come up with is that there was mirage even though it was unseen. it was causing a lensing effect and changing the site picture and point of impact. my final conclusion is, moving mirage good, no mirage bad.
 
Al

Since you bumped it, I guess I could relate this.

Last Saturday, Gene Bukys, Vic Smith, and I were at Tomball. I was trying to figure out why my Rail Gun seemed to be tossing shots when I "ran" a group.

I was shooting at 200 yards, and the conditions went to just about "zero'. Very strange for Tomball. I played with a few loads, and finally settled back into my "pet load" of 30.4 grns.

I waited untill the flags were all green, with no indication of movement, and slowly shot a five shot group that was about .180. I decided to see if it would do it again, and in the same dead condition, shot another group that was about .150. Keep in mind, this was at 200 yards.

So, it is possible to shoot very small groups in a dead still condition, but I still think the Rifle has to have an impeccable tune.

At least I know this barrel is capable of shooting at a competitive level.......jackie
 
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jackie schmidt said:
Since you bumped it, I guess I could relate this.

Last Saturday, Gene Bukys, Vic Smith, and I were at Tomball. I was trying to figure out why my Rail Gun seemed to be tossing shots when I "ran" a group.

I was shooting at 200 yards, and the conditions went to just about "zero'. Very strange for Tomball. I played with a few loads, and finally settled back into my "pet load" of 3.4 grns.

I waited untill the flags were all green, with no indication of movement, and slowly shot a five shot group that was about .180. I decided to see if it would do it again, and in the same dead condition, shot another group that was about .150. Keep in mind, this was at 200 yards.

So, it is possible to shoot very small groups in a dead still condition, but I still think the Rifle has to have an impeccable tune.

At least I know this barrel is capable of shooting at a competitive level.......jackie
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Well, so you got a "real" dead calm ....... :) a rare thing indeedy.

al
 
alinwa said:
Well, so you got a "real" dead calm ....... :) a rare thing indeedy.

al
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Indeedy. Not all calms are created equal just like not all puffs are created equal.

In the mouth of the canyon here at the Springville shoot, I have shot some itty bitty 200 yard groups in dead calms. But then I have had the voodoo there in the calms as well and it seems to be related to how hard the wind blew down the canyon in the morning and then how hard it blew back up in the afternoon. If the ground, grass, trees, and brush all got cooled or heated evenly by the predominant wind, then there seems to be less mirage and less air pockets or thermals when it calms down which would then let you drill bugholes. But if the wind doesn't blow much all day (extremely rare for Springville) then the ground gets heated up, the thermals rise, the wind flags are lifeless, and you get groups like a shotgun!


What brought this whole thread up was what happened in Colorado last weekend at the match. I was doing well, my gun was in tune, and the flags were moving nicely. I drilled a .191" in a full reverse and won the match and was in first place until a calm settled in for match 5 and my gun suddenly couldn't get two shots to touch. I finished out and dropped to 2nd in the agg. Then the next morning, the voodoo kicked in again and there was simply nothing to read but the straight .8's on the wailing wall! Me, no. The gun, no. The load, no. It was condition!
 
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It wasn't the dead calms that got you in Colorado, it was your load!

Remember that there were 40 degree temp shifts that were happening between the first target and the fifth target. That was sending your gun in and out and in and out of tune as fast as we were shooting.

From my notes, the temps were increasing at about 5 to 6 degrees per target until about half way through the second yardage both days. I shot the same load all the way through but had to constantly tweak my tuner to keep the groups together. By afternoon, the temp stabilized and the load would hang together for an extra target or two.

Rodney Brown
 
First let me say that I have no idea how to shoot a "dead calm", but the absolute third-from-best condition for testing loads on my home range is a "dead calm" where the flags aren't moving but the spiderwebs and 'wishes' (dandelion fluff and the like) are drifting in a stately fashion from right to left........ the second best is a light drizzle, a real WA drizzle which falls straight down and maps every little gust of wind.


The best "dead calm" I've ever shot is a perfect Christmas-Card snowfall. Snowflakes make GREAT windflags!

FWIW......'ZACKly what'cha' paid ;)

al
 
I'm witchya on the drizzle - -

alinwa said:
First let me say that I have no idea how to shoot a "dead calm", but the absolute third-from-best condition for testing loads on my home range is a "dead calm" where the flags aren't moving but the spiderwebs and 'wishes' (dandelion fluff and the like) are drifting in a stately fashion from right to left........ the second best is a light drizzle, a real WA drizzle which falls straight down and maps every little gust of wind.


The best "dead calm" I've ever shot is a perfect Christmas-Card snowfall. Snowflakes make GREAT windflags!

FWIW......'ZACKly what'cha' paid ;)

al
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I have shot and seen some of the smallest groups shot in drizzle. We aren't group shooters but shoot them when testing.
 
CubCouper said:
It wasn't the dead calms that got you in Colorado, it was your load!


Rodney Brown
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That's what one might think but I knew it wasn't that as I had mapped out the loads in this barrel in the same temps just a day beforehand and my shots were all touchin on matches where there was just even a little breeze of a wind.

After loading for guns long enough, you just know when they are working or not, when you're shooting well or not, and when it is conditions or not.
 
I keep reclling - - -

A match I shot in last summer at a range that is alomst totally protected from wind. the flags barely moved all day and it was sunny. I think I recall having 14 xes at the end of 4 matches. The last match looked to be the same as the previous ones but I did not get a single x that match. The two guys who beat me got 5 and 4 respectively. I would have won with 4 because I had 5 in my first match. I think now that either Wake Turbulance or mirage that I could not see through the 6 power scope got me. There was absolutely no movement in the flags or tails.
 
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Pete Wass said:
A match I shot in last summer at a range that is alomst totally protected from wind. the flags barely moved all day and it was sunny. I think I recall having 14 xes at the end of 4 matches. The last match looked to be the same as the previous ones but I did not get a single x that match. The two guys who beat me got 5 and 4 respectively. I would have won with 4 because I had 5 in my first match. I think now that either Wake Turbulance or mirage that I could not see through the 6 power scope got me. There was absolutely no movement in the flags or tails.
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My brother-in-law has 100yds through a slot in the trees. Wind or no wind it's an absolute BEAR to shoot a group in on a sunny day.

al
 
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