I can't tell for sure, are you mapping to 'World Space'? I just did a test with a cylinder and 'Diamond Plate' texture from the 'Miscellaneous' category. I had to change to 'World Space' and rotate the z-axis +15 degrees to get the sides right. On the ends the material looked different - but not distorted. Since the ends of your model is rounded, you might try making the ends as separate pieces, which could be mapped independently. Hope this helps.