it looks like you took the same texture and duplicated it onto the uvcoords of the barrel. What i would do is: in an image editor, change the attributes of the image to double your texture height, then create a mirror copy the texture on the vertical axis and place it underneath the original part in the new space created by adjusting the attributes (depending on what program your using this may require using an additional layer and merging it down...) From there add variety to the bottom half so that it doesnt look like a perfect mirror of the top half. This should eliminate the seem youve created in the middle of the barrel by duplicating the image in your uv coords. If you like i could give you a visual explanation when i get off work.
Edit Ruccus has a good tip as well. Using photo texture can be a good thing if used properly... a photographed texture is not always going to work for your model 100% of the time...(In fact it rarely will.) Use an image editor to tailor it to fit what you need. another thing you could do is make it tileable by ofsetting it and blending the resulting seem then duplicate it and add detail and varity to the bottom half.
Edit: Looking at it again i can also see that the top has the same texture pattern as the sides. Ill whip somthing up when i get home to show you what i would do.
