Watching the vapor trail

Discussion in 'Long Range Scopes and Other Optics' started by tracker12ga, May 7, 2010.

  1. tracker12ga

    tracker12ga Well-Known Member

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    Is a huge objective high powered scope really need to watch vapor trail consitently? I wa wondering if it is possible to do this with a quality pair of binos. if a spotting scope is needed, can it be a compact one?
     

  2. bigngreen

    bigngreen Well-Known Member

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  3. LouBoyd

    LouBoyd Well-Known Member

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    The main requirement for a vapor trail is to have an atmosphere where the dew point is near the ambient temperature. Then the sharply increased then decreased air pressure from the passing bullet will cause droplet formation. It's the same process as contrails off an aircraft. In Arizona most of the time vapor trails don't form at all. It doesn't take much of a scope to see the trails if they form. You can see them naked eye in good conditions.

    You may also detect the bullet path from the optical refraction of the air compressed by passing bullet. It's a smaller effect than a vapor trail and has no persistence. I've only noticed it shooting my 50 BMG. I see it though the rifle scope (14x50) usually at ranges from 300 to 600 yards and it's visible in dry air. The background makes a big difference in how visible it is. You'll see nothing with a uniform background (like sky).

    I don't find either very useful for determining where a bullet has impacted. Dust puffs from the ground are better in dry locations but don't happen on damp ground. Tracers work but each type has a limited burn duration. They can also start fires.

    All of the above are useful for estimating wind deflection.
     
    Last edited: May 8, 2010
  4. .30 CAL

    .30 CAL Well-Known Member

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    I use Nikon Action 10-22X50 binos set on 10 power. The easiest way to learn is to sit with the sun to your back and the shooter directly in front of you. Put the target in the lower portion of your sight picture not in the center. Once you figure out what to look for you can adjust your optics to catch the trail most of the time. My shooting partner uses Swarovski 15X50 binos and you can see the trail all of the time. Better glass makes it easier.
     
  5. tracker12ga

    tracker12ga Well-Known Member

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    Funny. I was using the same binos (Nikon Actions 10-22 x 50) watching the VTs. And you are exactly right. When the sun is at your back, you can see them quite well. I was watching them well even with a pair of 10 x 42 Bushys from walmart. However, this after noon at 1130am, while even shooting in an open field with mirage, we could barley see them at 500yds. And only then we saw them at the end before it got to the target area.

    Nevertheless, it wa good to find out that a pair of binos can get the job done. no more need to take a spotting scope in the field. One less piece of equipment.
     
  6. nfhjr62

    nfhjr62 Well-Known Member

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    Had never heard of this until i started to shoot X/C 30 cal. first time scoring saw it and didn't know know what i was seeing so asked once use to it was telling the shooter were he was hitting the target before it was pulled and marked.
    It helped me at a match at Bridgeville Del. as at 600 yrds. my 180 gr. HPBT Hornday's were cork screwing and not grouping(new load to me) switched to 180 MK's and only dropped five points, just last night watched on the History Channel a show on Snipers and were trying to duplicate the longest sniper kill on record and were showing the vapor trail of 50 cal. bullets in detail.
     
  7. Bravo 4

    Bravo 4 Well-Known Member

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    We were taught to use a spotting scope @ 17-20 power and get in line with the shooter as much as possible, or directly behind him. Put the target in the bottom 1/3 of your field of view, focus on the target and then bring the focus back to you a little. The atmospheric conditions play a role from day to day visibility and so will the caliber of the round. On certain days you can spot .50 cal rounds with the naked eye.
     
  8. Kevin Thomas

    Kevin Thomas Well-Known Member

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    The best? Something like the old 100mm Unertl Team scope, or the new Kowa Bino team scopes like AMU is using. The first is long since out of production, and teh second are more than a little pricey. Emil Praslick was showing off the new accquistion to me some time back, and I like to fell off my shooting stool when he quoted the price!

    Vapor trails are easily seen with any decent spotting scope. The new Kowa 82mms, the older 77mm models, or any others. Spent a lot of time in the military using the old issue M49 spotting scopes with very good results. For Rattle Battle matches (Infantry Trophy matches) the coaches are pretty well limited to using binos, since they don't have time to get behind each shooter if they're messing with a spotting scope. The important thing is that 1) the coach knows what he's looking for, and what he's seeing, and 2) that the coach is best situated directly behind and above the shooter, as closely as possible in each aspect. The first comes from time on the range an practical experience. The second does too, as he'll find out where he needs to be by spending some time in the coaching role.

    The bigger scopes are easier to use, but this really is a task that relies more on the skills of the user, than the tools he's using.

    Kevin Thomas
    Lapua USA