Range Report Bullet Trace

[rickp]

Hey guys,
Quick question. What are the optimal conditions for getting bullet trace. What I mean is, does it have to be cold with little humidity or hot and humid. If I had to assume or guess, i would thing that air that is more dense would give one a better chance to get trace.

Thanks
R.

 

[LawnMM]

Re: Bullet Trace

I've seen it easiest at altitude in the cooler mountain areas. Hotter conditions I've seen it less, I think you are correct in that the denser air allows the bullet to disturb more of it in flight and make seeing trace easier.

I can also believe that it would be masked or washed out by mirage depending how hot it is where you are shooting.

Rich

 

[shoepop]

Re: Bullet Trace

Living in the desert with average humidity of 15% you are not going to see a trace unless you shoot tracers. Your then likely to see a brush fire to go along with it.

 

[rickp]

Re: Bullet Trace

Mark,
See this is what I'm talking about. Less humidity more dense the air is, except for the heat, so I would think better chance for trace. I'm down in south florida so heat and humidity are off the chart. We shot Sunday and heat was 90 deg and 72% humidity, no trace what so ever.

R.

 

[notquiteright]

Re: Bullet Trace

I live in a lower humidity area. Mornings seem about the best time. High heat and humidity interferes with seeing trace. But so does high heat and very low humidity.

High humidity boosts the mirage effect and creates a gaussy curtain that is difficult to see through. Low humidity doesn't give the bullet much to work on. Somedays I can start out with great trace and by 1 o'clock just catch a fleeting glimpse at max ordinate.

Best trace ever was across a snow covered field early one morning, very bright day.

 

[9H_Cracka]

Re: Bullet Trace

Distance, background, light conditions, design/quality of your spotting scope, and placement of spotting scope in relation to the bore of the rifle greatly affect your ability to spot trace, regardless of humidity. Spotted many a trace is the low humidity of NM.

 

[turbo54]

Re: Bullet Trace

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rickp</div><div class="ubbcode-body">Mark,
See this is what I'm talking about. Less humidity more dense the air is, except for the heat, so I would think better chance for trace. I'm down in south florida so heat and humidity are off the chart. We shot Sunday and heat was 90 deg and 72% humidity, no trace what so ever.

R. </div></div>

Glass, position, and experience are the key factors. Ive seen it on days with a DA of 200ft and 20% humidity and 10*F, and I've seen it on days with DA of 4000ft, 90% humidity and 90*F.

 

[Early Cuyler]

Re: Bullet Trace

I would assume that instances of higher RELATIVE humidity is the key factor. Here's my reasoning:

During a bullet's path as air crosses over it the flow is (hopefully) laminar over the length except the tail. At the tail, a low pressure "eddy" forms. The sudden drop in air pressure will cause the water in the air to precipitate out in the form of vapor. Once the bullet continues out of the immediate area, the vapor will evaporate again and the trail dissipates.

Due to this, the higher the relative humidity the slower the vapor is able to evaporate back into the air. Therefore if the relative humidity is higher, the more water can be turned into vapor AND the longer the vapor (trail) stays in the air.

I have another way of explaining it if that didn't make sense.

 

[turbo54]

Re: Bullet Trace

The airflow over a bullet isnt anywhere close to laminar. Laminar flow happens at VERY low velocities and thus, Reynolds number. Rather, when talking ballistics of bullets, we're talking about compressible flow, and that is a very complicated subject that I cant speak very intelligently about.

I believe bullet trace has more to do with the shockwave than anything.

 

[rickp]

Re: Bullet Trace

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbo54</div><div class="ubbcode-body">The airflow over a bullet isnt anywhere close to laminar. Laminar flow happens at VERY low velocities and thus, Reynolds number. Rather, when talking ballistics of bullets, we're talking about compressible flow, and that is a very complicated subject that I cant speak very intelligently about.

I believe bullet trace has more to do with the shockwave than anything. </div></div>

I would agree, I think we're seeing the compressed air as the round cuts through it. Hence my original contention about air density.

 

[Early Cuyler]

Re: Bullet Trace

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbo54</div><div class="ubbcode-body">The airflow over a bullet isnt anywhere close to laminar. Laminar flow happens at VERY low velocities and thus, Reynolds number. Rather, when talking ballistics of bullets, we're talking about compressible flow, and that is a very complicated subject that I cant speak very intelligently about.

I believe bullet trace has more to do with the shockwave than anything. </div></div>


That was my mistake. Yeah the shockwave idea makes more sense to me now. I got sucked into the "I know just enough to let everyone know how little I know" train of thought and got too fancy.

Occam's Razor right?

 

[trident1982]

Re: Bullet Trace

I have been extensively refining my personal setup for LR filming/tracing over the last half year and ultimately at least in my locale, the actual setup, positioning, and capturing device have far more to do w. putting quality trace on film than environmental conditions imo.

I do believe that having heavy humidity present seems to produce a better product, however if I had to pick one environmental factor that was most important in my own process it would be the amt. of sunlight present/direction in relation to my firing position and then my target. I only shoot w. the sun at my back, and personally I love to shoot the last 2-3hrs prior to dusk/2-3hrs after dawn. Blue bird, extremely sunny days are the only time I cannot produce trace from a session, moreover I have captured trace on one occasion during a light rain fall in the evening w. significantly overcast skies.

I shot this video last evening using a MRP SPR @ 675yds on a CMP 12"x 20" steel target. It's more than worth the price of admission capturing trace from a session and then coming home and playing/studying it much like a ball coach does for his teams previous game.
<object width="425" height="350"> <param name="movie" value="http://www.youtube.com/v/xYU9Fo-kQiw"></param> <param name="wmode" value="transparent"></param> <embed src="http://www.youtube.com/v/xYU9Fo-kQiw" type="application/x-shockwave-flash" wmode="transparent" width="425" height="350"> </embed></object>

 

[VKC]

Re: Bullet Trace

I think being able to see a bullet trace has to do more with distance, magnification and angle. I shoot in the desert and at high altitudes all the time, but still see bullet traces. At further distances (e.g. beyond 500 yds), you have more time to see the bullet and the arch is higher to compensate for drop, that is when I see the bullet trace better. I also tend to see trace better on high magnification such as with a spotting scope better then with lower magnification.

 

[Sendero_Man]

Re: Bullet Trace

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: _9H</div><div class="ubbcode-body">Distance, background, light conditions, design/quality of your spotting scope, and placement of spotting scope in relation to the bore of the rifle greatly affect your ability to spot trace, regardless of humidity. Spotted many a trace is the low humidity of NM. </div></div>

Yup, same here. We shot Sat. up in Montana at 85 degrees, 38% humidity and got great trace.

Conditions were...
Spotter behind shooter, Sunlight behind both shooter and spotter, Zeiss spotting scope on tripod. We got great video of it at 630 and 780 yards.

Will try to post up video of it. Used a Zeiss digiscope and small camera with HD video capabilities.

 

[trident1982]

Re: Bullet Trace

You can always just cheat...use a tracer

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[tnichols]

Re: Bullet Trace

A little trick that works for me is that when I'm spotting for a buddy, I put the target in the "corner" of my scope, and not dead on like I'm shooting it. Perhaps, I should have said the far corner of the scope. It lets me see his bullet longer as it travels across my field of veiw enroute to the target. Does this make sense or does anyone else do this?

 

[LoneWolfUSMC]

Re: Bullet Trace

It is my recollection that I usually have an easier time seeing trace in lower humidity. I don't know that there is any science to back it up. That just seems to be trend in my recent memory.

Not a lot I can do to control it, so I don't much worry about it. Either you can see it well or not as well. I don't recall any situations where I couldn't see it at all once I finally learned what to look for years ago.

 

[RTodd]

Re: Bullet Trace

I've shot high power matches in Wyoming's Red Desert, as well as Ft Benning GA sauna. My impression is that a good background (matte black target paper) and good glass (I use a moderately priced Kowa TSN821) will allow you to see the trace every time, barring truly horrible light. Focusing mid way to the target instead of on the target surface helps as well. Bullets in flight looked like a disturbance of the mirage, but you could call scoring ring and position with 90% accuracy. The bullets reminded me of an angry hornet headed downrange in a hurry.

 

[bohem]

Re: Bullet Trace

I've since pulled the images down to make space online, but here's a thread which delves into the topic.

http://www.snipershide.com/forum/ubbthre...081#Post2007081

Like LoneWolf said, once you see it a few times and realize what to look for, seeing it all the time becomes very easy.

Probably the best view I got of trace was a very humid, mid 80's day overcast. There was no mirage and the 6 Rem AI was literally pulling a vapor trail you could see with the naked eye for about 400yd. With a scope watching the target the trace was extremely obvious.

 

[Skyking]

Re: Bullet Trace

<object width="425" height="350"> <param name="movie" value="http://www.youtube.com/v/NWd1YYouuNQ"></param> <param name="wmode" value="transparent"></param> <embed src="http://www.youtube.com/v/NWd1YYouuNQ" type="application/x-shockwave-flash" wmode="transparent" width="425" height="350"> </embed></object>

Here is one of my many videos with it. I think one of the biggest keys is the spotter needs to be directly behind the shooter.

Watch on full screen 720P will give you the best results.