500NITRO is right, the most important thing is lighting, and second is the background!

Use a tripod, and timed release, and turn the flash off. The Macro settings will give you the best quality if close detail is wanted, like with an open double rifle! Once set up, focus the camera, set the timer, and let the camera do the rest. With digital cameras, the best thing about them is you can blow the pictures up to quite large without looseing quality!

All the advice above is from a rank amature, so be guided accordingly!