What affect does rain have on accurracy? More specifically, I was testing loads for my .308 a few weeks ago. It has a steady rain. My group POI did not shift, but my groups opened up. What affect does a rain drop have on a 30 cal. bullet at 100 yards?

At 3000 fps it reaches the target in 1/10th of a second. Even in pouring rain I think I read somewhere (hows that for qualifying a statement) that there is < a 1 in 100 chance of the bullet hitting a raindrop. Humid air is a lot less dense than dry air, so the bullet should get to the target quicker and with less drift, all things being equal.

(IMHO!)

I have heard of rain shots but have not had a problem with rain unless it gets into the muzzle. Butch

Butch,
I have a target shot at the super shoot last year that has four shots in about a half inch with one shot making it into an inch group. The shot that is out doesn't have the same black ring around it that the other four have. Smiley Hensley had one that did the same thing on his. Rain was coming down pretty heavily at about a 45 degree angle and had to aim on the outside ring to get the group to hit a little right of the 10 ring. I'm pretty sure it was caused by hitting a rain drop and not from water getting in the barrel, but would be hard to prove.

Mike

Mike, I'm not saying that it doesn't happen, just not to me yet. I have heard from very knowledgeable shooters that they have had a problem. Most notable was Ed Watson at the Crawfish shoot a few years ago. He was on bench one and had 2 horrible groups. I was on bench 2 and had my best two groups. Go Figure. Butch

I'm not an expert, but I have shot in rainy conditions several times at the range, and can honestly say I've never noticed any difference at all unless the rain was accompanied by windy conditions. Just one mans opinion. Best wishes.

Cal - Montreal

I shoot F class and never under a covered firing position, and the rain bothers me a lot more than it bothers the bullet. Of that I am convinced. I can honestly say, I have never dropped a point while shooting in the rain that I could blame on the rain. Missed wind condition change yes, but not the rain. I learned real quick to keep your ammo dry, and your chamber dry as best you can. When shooting in the rain blown primers from wet ammo/chambers does cause pressure issues. I am sure most of you have seen pictures of bullet stopped in flight. The pressure ridge for lack of a better discription around the bullet as it flies through the air keeps rain from hitting it I have been told by some pretty knowledgeable long range shooters. I know one thing, I hate to dry out a wet ammo box.

PaPa 260

quote:

Originally posted by butchlambert:
I have heard of rain shots but have not had a problem with rain unless it gets into the muzzle. Butch

I agree with Butch. I have seen some very strange groups shot in the rain but I believe the cause was rain in the muzzle, not the bullet hitting a rain drop.

Ray

Rain effects the shooter more than the gun.

I used to shoot competitively, and we always practiced rain, snow, or shine.

On the odd chance that the competition was held in the rain (and it happened a few times), you could really tell the difference in the fair weather shooters vs those who had practiced in it.

I forgot to mention that earlier this month the F class national championships was held at Oak Ridge. The 600 yard stage was shot in a steady rain that fell all day. The wind was dead calm a true no wind condition. A new national record (150-14X) was set that day for the 600 yard stage using the 300 yard High Power target. That is a challenging target for sure. Several shooters shot clean scores with excellent X counts. And there was several blown primers from wet ammo and chambers by those who didn't keep both of them dry. I agree with crazy_quick, it bothers the shooters a lot more than it does the gun or the bullet. I do believe that if rain got in the barrel it could do strange things to a bullet.

PaPa 260

Hey Guys,
This was debated for a stretch on some other sites, and the general consensus coming from folks with a higher education, was that the bullet traveling down range creates a disruption in the air flow all around it, including the front. This air barrier would in fact deflect any rain before it could come into contact with the bullet in flight, as would the significant heat generated by the bullet in flight, due to the friction of pushing through the air.
The information about higher humidity does play into it, but obviously wouldn't necessarily result in your groups opening; more likely a change in POI.
I hope this helps.
Respectfully,
Harry

There is another view to your question about the rain. I believe the accuracy would be affected more by how the shooter deals with the rain in his mind. A shooter annoyed by the rain will not shoot well.

I live in the Pacific Northwest. Shooting and hunting in the rain is a way of life here. I have noticed no difference in fifty years of shooting. Of course if it rained so hard you couldn't see the target it would make a difference in your groups I'd guess.