Here is my attempt at scratching an ammo crate. It still needs some tweeking, which is why I thought I would post it. Any tips would be greatly appreciated!
1.Started with 2.5 x 0.5 evergreen strips, and used an ammo box from an old kit for the rough dimensions.

2. Dragging an exacto knife along the stips create rough wood grain and knots then cut the strips to size.
3. Use a metal file and the exacto to create rough edges and nail holes.
4. Using double sided tape to hold the small pieces together glue all parts.
5. Paint with various wood tones and browns ( I used wood, leather and rust)
6. Wash with a dark brown or black and wipe excess.

The last couple of pictures were taken just to see how it will look with different models. Its only one side of the crate, I didnt want to go through the trouble of building the whole thing just to hate the results. I plan on doing a little "messing around" with a couple more panels untill I'm completely satisfied with the results.

11 attached images. Click to enlarge.

Thanx Walt, I'm pretty happy with the results. I think next time I will try the sandpaper method to get the wood grain effect. I should also mention that it will probably take one piece of the evergreen strip to make one crate which is pretty cheap considering the alternative ressin or wood after market products.