Here's something to do with empty bottles. Clear ones work best. I used some old medicine ones that I have.

You'll need:

Painter Tape

Primer (Spray)

Paint (Spray)

X-acto knife

Bottle

Design

Step 1:

Find a design that appeals to you. I printed out a paw pattern at 50%. I've found that the more intricate designs lose a little of their crispness. This time I went with a bold pattern.

Place a few overlapping strips of painters tape on a cutting surface. Trim the pattern and place it over the tape. Now tape the pattern down.
Using an X-acto or other sharp blade, carefully cut out your design.

Step 2:

To create the window to keep track of the ammount of ammo within the bottle, slice a strip of 1 inch painters tape in half.

Measure the tape against the bottle and create tick marks, about 1/2 inch apart.

Place the tape along the side of your bottle, then use the knife to carefully slice ONLY through the tape.

Remember: whatever you leave covered will be clear.

Step 3:

Carefully cover the threads on the top of the bottle as well as the cap. The paint can gunk up the ability to close and open the bottle easily.

If you want your design to be clear, skip to the next step, then prime.

I wanted a two tone design for this bottle. I laid down the white primer first. You'll want a primer that adheres to plastic, usually Krylon or any indoor/outdoor spray primer.

One coat should be enough, just spray light and even. Allow it to dry.

Depending on the humidity and temperature, it should take anywhere from 10 mins to an hour.

Step 4:

Carefully peel your cut design from your board, making sure the overlapping tape stays together, and place it on your bottle. Do this slowly as your flat design will usually be on a curved surface.

Make sure all the edges are firmly pressed down and that any air bubbles have been worked out.

Take your bottle back outside and with short even shots, spray paint it. I used Rust-oleum Dark Multi-Color Textured paint, as I liked the look. I also like the grip it gives to the bottles.

Let it dry anywhere from 1 to 3 hours.

Step 5:

The next step is my favorite.

After your bottle is completely dry, it's time to carefully peel the tape from it. Find an edge with the tip of your knife and gently peel away the tape.

Viola! Your design is revealed! Now, just fill with pellets and your good to go.

I made a few of these with my nephew, for him and his friends. They seem to get a kick out of them.