One of our serious shooters hangs a pc of yarn on the bottom edge of the backer at 50yds. I think that when my bullet gets to that point the wind damage has been done.
I searched for "DIY wind flags" and found several ideas. Having made my own wind flags in the past, I can offer the following advice:
- It's a lot easier to make good flags of you have a lathe to turn and center drill some of the parts, such as the pivots. But it can be done with a drill press.
- Materials for the flags should be light, but strong. Fiberglass, aluminum, strong plastic, for shafts. Celloplast sign material for tail vains, etc. Flags can take a beating while you're moving them to and from the range if you're not very careful.
- Pivot sensitivity is important. I use center drilled delrin or nylon for the pivots. Pin in hole. Some people use bearings.
- Balance is important. 50-50 front to tail, or slightly tail heavy. A flag that's nose heavy will "hunt" or oscillate. You'll want to be able to move the pivot point back and forth to get the right balance and then make sure it stays where you put it.
- Surveyor's tape or braided yarn for the tail. Depending on the max range you'll be shooting, make sure the tail will be visible.
- Prop or solid piece for the nose. As indicators of wind speed, props are basically useless in anything but a slight breeze. More than about 5 mph of wind, the props will probably be spinning too fast to tell you anything. Main indicator of wind speed is the tail. Nose piece should be about the same weight as the entire tail assembly.
-You can make stands out of a pole and two 2x2 pieces of wood. But you should incorporate a way of adjusting them to be perfectly vertical when you set them up. If the stand is leaning one way or the other, it won't point accurately. This means you'll want to think about how you'll be able to tell if they're vertical. I use a bullseye level screwed to the top of a piece that slips over the pivot point on the stand. Before you build the stand, decide how tall you want your flags to be. Top of flags below bench height is probably best. Allows you to set the flags in a direct line between you and the target without worrying about shooting holes in them. Otherwise, you'll have to set them up off to one side.
- It's enjoyable to experiment with making your own flags, but if you're serious about using flags while you shoot, you'll probably end up buying some. I got a set of four flags, with tripod stands, made by Danny Keeney. Killough shooting sells them for a reasonable price and they work fine.