Two approaches make all the difference in the world.

1) Use soft light. Indirect natural light is ideal. Before I had any kind of light setup this is what I did. My bedroom has west-facing windows, and I would do my photography in the late morning before any direct light would come in.

Using this method there's never enough light, so you must help things along with your camera settings. Your camera will want to open the aperture to the max. That won't work. Your focus will have no appreciable depth of field and will be so shallow that parts of the gun will be in focus and parts out of focus. You need a smaller aperture to get more depth of field.

2) Set your camera on a tripod. Use the timer delay to trip the shutter. You don't want to be touching anything when the shutter trips. Go to manual settings and set your aperture to f16 or thereabouts. Your camera will compute that your shutter speed will be something like 1/8 to 1/4 second. Not to worry. Nothing is going to move during this exposure. You can get wonderful photos using this method.

Your camera doesn't have to be a big dollar machine.

And finally, you don't want to use a flash.

One thing good about it, you can keep trying and it costs nothing.

Hope this helps.

Curl