Low-poly wood barrel

Which of the two? Dark or Light?

I like them both. But if I had to choose, I would pick the "Light" one.

Ok, thanks 

Some more improvements, you can think about: If you're going for realistic, get rid of the dark dots in the texture around the middle, that look like nails. They wouldn't make sense in a barrel. It looks like the texture was a boarded floor.
You could add 2 other metal strips, one at the very top and one at the bottom.
The top and bottom faceloops, that create the area, where the planks would have been sawed off, could be made to look as such a cross section in the texture.
And to enhance the model some more, select the inside edge loops at the ends of the barrel and move them towards the vertical middle a little (loop at the top moving down, loop at the bottom moving up). Make sure to activate "move vertex along edge" to keep the thickness constant.

There's also plenty space in your texture. You could use that for other stuff that could be put inside a barrel, for creating variants, or you could scale down the UVs of the barrel, so that the grain and bottom blanks of the barrel fit besides the rest and you can cut off the upper part (1024x512), thus saving memory.

Some more improvements, you can think about: If you're going for realistic, get rid of the dark dots in the texture around the middle, that look like nails. They wouldn't make sense in a barrel. It looks like the texture was a boarded floor.

Damn, i forget about nails

You could add 2 other metal strips, one at the very top and one at the bottom.
The top and bottom faceloops, that create the area, where the planks would have been sawed off, could be made to look as such a cross section in the texture.
And to enhance the model some more, select the inside edge loops at the ends of the barrel and move them towards the vertical middle a little (loop at the top moving down, loop at the bottom moving up). Make sure to activate "move vertex along edge" to keep the thickness constant.

I will try to do it..

There's also plenty space in your texture. You could use that for other stuff that could be put inside a barrel, for creating variant

which variants? For example, a cap with grain or a cap with sand?

or you could scale down the UVs of the barrel, so that the grain and bottom blanks of the barrel fit besides the rest and you can cut off the upper part (1024x512), thus saving memory.

unfortunately, Nvil does not support a different width/height, only 1024x1024/512x512 etc

which variants? For example, a cap with grain or a cap with sand?

exactly.

unfortunately, Nvil does not support a different width/height, only 1024x1024/512x512 etc

My bad. Scaling down the UVs wouldn't work with a non-square texture. The UVs should still occupy the 0-1 space (or more for tiling). In Maya the non-square textures are stretched to fit 0-1 space, or one can switch to stretch the space, I believe. Nevertheless, I just loaded a 512x1024 map into NVil and opened up the UV editor. The space gets adjusted to match the texture resolution.