Shooting in the rain

[swampshooter]

While shooting an F-class match in the rain yesterday the question was brought up about the effects of the rain on bullets. Several (not all) of us agreed that the rain had little or no effect on the bullets but nobody knew for sure what takes place to negate any effect of the rain on the bullets. Your thoughts please.

 

[Tim Singleton]

There was a big long discussion on here not to long ago. Search on this site. It wasn't to long ago. It got long pretty quick

 

[Toby Bradshaw]

http://forum.accurateshooter.com/index.php?topic=3864243.msg36517115#msg36517115

 

[jr600yd]

Heheh my bullets just fly between the Drops!

 

[KevinThomas]

There's frequently a pretty big difference in performance when firing in rain, and it's not what most folks assume. Your trajectory will flatten out a bit, as though the bullet has a higher BC. It's not due to the rain itself, per se, but the fact that you get rain when the barometer falls; you're shooting through thinner air. I've seen some significant differences with some calibers when a front like this hits. Worth keepin track of, anyway.

 

[Berger.Fan222]

There's frequently a pretty big difference in performance when firing in rain, and it's not what most folks assume. Your trajectory will flatten out a bit, as though the bullet has a higher BC. It's not due to the rain itself, per se, but the fact that you get rain when the barometer falls; you're shooting through thinner air. I've seen some significant differences with some calibers when a front like this hits. Worth keepin track of, anyway.

Kevin, Thanks for your input. If I understand you correctly, the effects you are talking about would be accounted for completely by reading the pressure, temperature, and humidity with a Kestrel and entering the data properly into a ballistics program. Is this right?

 

[jim_k]

When there is a lot of water vapor in the air, the air is less dense, since water vapor is less dense than dry air. That seems counterintuitive, since water is a lot more dense, but we're dealing with water vapor, and it is lighter than dry air. Ergo, better ballistics given all other air density values being the same. However, I have shot some very small groups at 100 yards when it was raining, if that's what you're talking about. I cannot explain that, but I have observed it. Therefore, it may be anecdotal, and not valid or scientifically demonstrable. It could be related to having "stable air." That can be measured, and appears on aeronautical charts as the "lifted index." Where the lifted index is high, the air is less stable. There might (and now I'm really reaching) be some optical effects in operation, too. That is, water vapor and/or rain might produce a decreased amount of scintillation/flickering in the air. I would need a tool to experiment with, but I haven't been able to convince anybody to give me one. Jim

 

[Bryan Litz Ballistics]

The major problems I've encountered shooting in the rain were related to wet ammo going into the chamber (increases pressure and you get shots off call) and keeping the rain off your optics. If you can keep your ammo and sights dry, the bullet has no trouble getting to the target.

Personally, I think the chances of bullets actually encountering raindrops during their path to the target is rare. If the rain isn't so dense that you can see 1000 yards, and the bullet is only poking a .30" hole in the air for ~1.7 seconds, good chance it doesn't get wet.

Most of my experience with the rain has been as a shooter. However I had a chance to coach some FTR shooters in Canada last year. For those who remember the Canadian Nationals, it was wet. While coaching, we watch the bullet trace as it goes downrange thru a spotting scope. While watching this in the rain, on several shots I observed a distinctive 'white burst' along the bullets path. Sometimes it was close, other times far. On one particular shot, there where two distinct 'white bursts' at different points of the trajectory. All of these shots were white bursts were observed landed in with the group.

Based on this, it's my belief that most shots don't hit raindrops. Those that do are not substantially deflected.

Worry about keeping your ammo and sights dry. And as Kevin stated, note the pressure affect on your atmospherics.

-Bryan

 

[premo 2]

Rain X : :

 

[Canadian bushman]

Not real scientific

https://m.youtube.com/watch?v=UusiTSu1tSU

 

[Rustystud]

Rain has more effect on your barrel. Yes, If rain drops get inside your barrel and the bullet passes over them the water does not compress without an effect. I have never recovered a bullet after being fired down a wet bore. I have examined many barrels after they were shot wet. They have dents formed into the barrel that can ruin your barrel. I think the F-Class Rules Committee should amend the rule, saying to shoot in the rain unless there is a danger of lightning, or the targets can not be seen. Several years ago a number of top shooters had their barrels ruined shooting in a match in Bisley England.
Nat Lambeth

 

[dcali]

Just a thought experiment: What would be the chance that a bullet just sitting on the ground would be hit by a rain drop over a period of 1.5 seconds? That's probably about the same chance that it would be hit in flight. In a downpour, probably fairly likely. In a light rain, probably not very likely.

 

[spclark]

[

... it's my belief that most shots don't hit raindrops. Those that do are not substantially deflected.

Brian I'm nowhere near the bona fide engineer you are so I'm going with your belief as gospel. Prior to this thread I'd assumed any rain drops in the path of a supersonic bullet's progress down range would never touch the bullet itself owing to the effect at the boundary layer surrounding said projectile and the shockwave that propagates through the air it passes thru.

Those white puffs you mention maybe drops being vape'd, taking a bit of energy off the rotational momentum but not enough to change POI.

Now a bullet hitting say, a sea gull - as has happened during events held at Camp Perry for instance - is another matter entirely.

40 years ago I drove a new SAAB thru a puddle that was up to its hubcaps. Gal in front of me balked, I slowed & her wake swamped me. Engine died.

Literally.

I kept one of the connecting rods the mechanic who rebuilt it handed me a couple of weeks later, mostly as a reminder that water does not compress.

You don't want watet in your chamber or barrel, or the round you intend to put in next either.

 

[KevinThomas]

I'll add one more thing about rain here; the effect it has on shooters. In looking over my logbooks many years ago, I realized that over half my points towards my Distingushed Rifleman's badge were earned in matches that got some degree of rain. In this capacity, it's all about headspace; that between the shooter's ears. Some shooters just give up when conditions start working against them, and others don't.

Be one of the one's who don't!

 

[swampshooter]

I would like to thank all who took the time to answer. I appreciate it very much.

 

[Berger.Fan222]

I'll add one more thing about rain here; the effect it has on shooters. In looking over my logbooks many years ago, I realized that over half my points towards my Distingushed Rifleman's badge were earned in matches that got some degree of rain. In this capacity, it's all about headspace; that between the shooter's ears. Some shooters just give up when conditions start working against them, and others don't.

Be one of the one's who don't!

Agreed. All my first place finishes were on rainy days with Berger bullets.

 

[XTR]

From what I have seen in wet shooting conditions you don't get increased pressures per se in your chamber/rifle, but you will likely experience get increased bolt thrust from the case not gripping the sides of the chamber and you can get dented case shoulders (which could cause a pressure issue) if there is enough water in the chamber or on the round.

The bolt thrust can manifest to the point of of not being able to lift the bolt without great force.

 

[rmist]

Rain has more effect on your barrel. Yes, If rain drops get inside your barrel and the bullet passes over them the water does not compress without an effect. I have never recovered a bullet after being fired down a wet bore. I have examined many barrels after they were shot wet. They have dents formed into the barrel that can ruin your barrel. I think the F-Class Rules Committee should amend the rule, saying to shoot in the rain unless there is a danger of lightning, or the targets can not be seen. Several years ago a number of top shooters had their barrels ruined shooting in a match in Bisley England.
Nat Lambeth

I would worry about this more than anything !! I have seen barrels ruined at short range BR matches as well. How would you protect your investment with the rain coming towards your muzzle and not shooting over water droplets in the bore ?

 

[jsthntn247]

From what I have seen in wet shooting conditions you don't get increased pressures per se in your chamber/rifle, but you will likely experience get increased bolt thrust from the case not gripping the sides of the chamber and you can get dented case shoulders (which could cause a pressure issue) if there is enough water in the chamber or on the round.

The bolt thrust can manifest to the point of of not being able to lift the bolt without great force.

I've had lapua get stamped on my bolt face from the increased thrust of damp cases in 100% humidity. Also my case necks seem to get a light brown/goldish haze on them when shooting in the rain or ammo that has set out in very high humidity for a while.

 

[spclark]

How would you protect your investment with the rain coming towards your muzzle and not shooting over water droplets in the bore ?

Those of us who shoot with 'bloop-tubes' (sight radius extender for match sights) have a small advantage here. F'ers might want to maybe have something in their kit of a similar nature to put onto the end of their barrel in such conditions. May alter 'tune' a bit but then shooting in the rain does too....

Other than that just keep your muzzle pointed down 'till you center up for the next round!