Shooting for groups over a lake.

[Puzzaz01]

just a thought".......... a few weeks ago at a match I heard a few guys talking about shooting across a pond or lake at a few hundred yards and one guy was saying when he shoots over water it messes with his groups. I find that hard to believe, how does a bullet know if it's flying over water or solid ground? The only thing I can see making a difference is the inability to place flags out.

Darrin

 

[alinwa]

He's right

 

[group therapy]

He's right

why, increased water evaporation? different ground temp?

 

[luckeeshot]

air density and humidity

 

[Puzzaz01]

He's right

Could you elaborate a little with your conclusion..

Darrin

 

[Dusty Stevens]

If you ever fly a small plane across a lake at low altitude youll be a believer too

 

[Depart123]

just a thought".......... a few weeks ago at a match I heard a few guys talking about shooting across a pond or lake at a few hundred yards and one guy was saying when he shoots over water it messes with his groups. I find that hard to believe, how does a bullet know if it's flying over water or solid ground? The only thing I can see making a difference is the inability to place flags out.

Darrin

It is an optical effect, not a ballistic one. The refraction of light off of the waters surface makes you see the target in a slightly different location than it actually is.

 

[alinwa]

Could you elaborate a little with your conclusion..

Darrin

Not really...... I've not spent time assessing nor testing "why" just, having done it, it's a waste of time. A friend put in a range over a farm pond. Hadda move the range. Now, any given day you can still shoot there...... shoot some groups, walk 100ft and shoot some more over the pond.

Here are some more.

I shoot in my yard whenever I want. I can shoot under lights. We've been shooting trap under lights for 25yrs. I wired my range, I can light to 100yds. I have power down on the target. I've shot at 2:00AM, I can..... any day.

But I don't. It's a waste of time. Shooting at night, unless it's windy is no good.

A few yrs ago I was shooting out the window in a Christmas Card Snow..... best windflags ever...... I din't want to quit.

So I didn't.

Into the night.

Then the snow stopped falling..... the moon came out and you could play baseball by Thee Light of Thee Sylverye Moone....and I had to stop shooting cuz, Gremlins.

Perfect morning, sun hits the dew, Gremlins.

Crystal clear moonlight over frost, Gremlins

DEAD lull before a thunder storm, Gremlins

But shooting over water is just........ weird. I've never spent the time to figger it out but Harold Vaughn talks of "slow mirage".....

I just don't shoot over water.

 

[Uthink Uknow]

It's all about mirage.

 

[snert]

On the east coast Crawford Hawlidge (I know I spelled it wrong) had a range that was over a pond. Some of the earliest BR shooters shot there. Maybe a few salty saints recall that? I have seen photos of it.

 

[JMayo]

Im thinking it's about gravity. Gravity is denser the closer you are to the center of the earth and opposite the farther.....
Guys that hunt in the mountains, shooting across a valley what say you ?

(I know my golf balls are attracted to water, btw !)

 

[Laurie]

(I know my golf balls are attracted to water, btw !)

Growing up in Scotland (original home of golf I believe), I often saw the truth of this statement. Put a golf course anywhere near a pond, ditch, lake or river and they have a strange attraction for golf balls, especially super-expensive premium brands - a sort of 'Twilight Zone' effect if you remember the TV series.

I spent many summer days fishing a deep pool on the River Tay in Perth adjacent to a course with a high berm and mature trees between me and a fairway. Every so often there would be the thwack, thwack noise of a ball ricocheting through the trees and due to some effect of a kink in the course it'd normally then fly just over my head into the river, usually still close to the bank and visible, but as the river bottom fell away sharply sitting under a few feet of water. Shortly afterwards, there'd be a follow-on occurrence as the ball's owner swished around the long grass below the berm seeking his ball until I pointed out its location (with a degree of concealed schadenfreude not to mention completely false outward sympathy). As the Tay is tidal there, an ebb tide often allowed subsequent recovery and I could have made up for days that rarely produced a fish by selling the better recoveries, but as my father was a golf addict they went to him, and I was lucky if I got an ice-cream as a thank you.

As to shooting, I'd never heard of over-water effects before, but nothing surprises me when it comes to things that affect external ballistics and make life harder. It often surprises me that we can hit a target at all never mind consistently!

 

[Park ranger]

Hmm, I’ve set my scope up on a lake and I can never see mirage over water. It’s this is true, I’m not buying mirage. I’d bet it’s wind

 

[Dusty Stevens]

Hmm, I’ve set my scope up on a lake and I can never see mirage over water. It’s this is true, I’m not buying mirage. I’d bet it’s wind

It has to do with the density of the water and the updrafts from evaporation or something that i dont know. I do know a cessna drops altitude when youre low and go over a lake and takes more power. Cant explain why

 

[Texas10]

Humidity makes the air less dense. Engine develops less power, wings less lift. My Ex took a dunking while flying over a lake in a Stearman. Both got out alive, but it was 6 years later when the reservoir went almost dry that it was recovered, rebuilt and returned to flying.

Also makes landing a float plane easier. Take off's a bit harder, especially during a hot, summer day when temperature adds to the misery.

 

[284winner]

In some locations that do not have places to set up for ELR shooting opportunities, a lake is the answer. Why not wait until the lake freezes ? Winter. Easier to access the targets and very little if no human traffic. Some locations offer mile shot opportunities. Check with local laws as some states may not allow it. Many lakes in my region have small islands in the lakes that actually mound up from rock and brush/trees. Good back stop and safe shooting with no homes or cabins on the shore.

 

[Laurie]

Humidity makes the air less dense. Engine develops less power, wings less lift. My Ex took a dunking while flying over a lake in a Stearman. Both got out alive, but it was 6 years later when the reservoir went almost dry that it was recovered, rebuilt and returned to flying.

Also makes landing a float plane easier. Take off's a bit harder, especially during a hot, summer day when temperature adds to the misery.

That's interesting. More humid air will affect a bullet's behaviour as it reduces drag. The original Point Mass Ballistics Solver program that Bryan Litz provided with his Applied Ballistics for Long Range Shooting book had a humidity field incorporated and you could see this element reduced elevation requirements and wind drift, increased terminal velocities. Not by huge amounts, only marginally in fact and not enough to make a difference to settings and wind readings even at long ranges. Running 85% humidity v 0% for the 185 308 Juggernaut at 2,750 fps Mv only adds 6 fps to the 1,000 yard retained velocity, hardly affects elevation, and reduces 10 mph wind drift by 0.6 inches.

My home range in a wet and windy upland northern English valley often has a humidity forecast in the 80s to mid 90s % so I was always interested in this factor. We get some weird elevation effects mostly through wind effects we believe, but there is also a common view that with the constantly and rapidly changing conditions seen on the range of hills that banks of warmer or colder air might pass down the valley and affect drag enough to change elevations too. Maybe shooting over water sees similar effects.

 

[243winxb]

Change in earth's gravitational pull over water? What if a large underground rock is in the bullets path?

 

[JMayo]

Change in earth's gravitational pull over water? What if a large underground rock is in the bullets path?

A blip wouldn't do much but a mountain under the water might..
I'd still like to hear from a hunter that shoots from mountain top to mountain top.

 

[hogpatrol]

just a thought".......... a few weeks ago at a match I heard a few guys talking about shooting across a pond or lake at a few hundred yards and one guy was saying when he shoots over water it messes with his groups. I find that hard to believe, how does a bullet know if it's flying over water or solid ground? The only thing I can see making a difference is the inability to place flags out.

Darrin

Someone mentioned airplanes. I can tell you this. To the pilot, when their single engine aircraft flies over water, the engine automatically starts running rough. It's probably the same with those few guys.