I made a toy cannon made of gold and wood, but the gold color is not coming right. Here is the image:
I tried using the real IOR value and color, but nothing is working out. IOR value of .47 gives it a weird look.
Gold Base color Hex value: FFE39D
Node setup:
Please advice me to make a real gold material 
Can you show us a render. It would be much easier to advise a solution if we could see the outcome you are seeing.
For gold I usually add some roughness, so that the reflections arent that sharp. In my opinion that adds a lot to realism.
According to Blender Guru (Andrew Price) an IOR less than ‘1’ yields odd results. He advises ignoring real-world IOR settings for metal materials. You might try setting it back to the default (or close to it) and if that’s better.
the RGB value of metallic gold is: 212, 175, 55
The color of gold largely depends on what other metals are mixed in. See the google result for gold color: https://www.google.nl/search?q=gold&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwiayuLszrrTAhVFZ1AKHbvTDBsQsAQIQg&biw=1366&bih=638#tbm=isch&q=gold+color
You may want to have a look at this.
Fresnel for metals isn’t straightforward. But the approach used in the paper is more than suitable for rendering purposes.
In linear space gold should be 1.022, 0.782, 0.344, meaning it’s actually out of gamut for what your monitor can display. If using these I would normalize to stay safe, but I prefer to just pick colors from the chart. You can also use this for a base color and tint it sharply towards white at the edge. Things doesn’t have to be all that accurate. Gold’ish, wrt color, is usually sufficient.
To make it look good, put more focus with the roughness and environment.
Fresnel < 1 is to be avoided unless you’re inside the denser substance. Consider a block of water. Water has IOR of 1.33 when looking from air into the water, but 1/1.33 (=0.75) when looking from inside the water into the air. That would create snells window,or what you called that “weird look”. Fresnel node takes care of this automatically, but require that normals are oriented the correct way. For single sided thin surfaces you have to use normal IOR for regular face and 1/IOR for backface so that after fresnel inversion they both get equal. I really wish Cycles had a faster builtin way of handling thin surfaces.
Ah sorry - I thought you posted the link as an example of what you were trying to achieve.
IMO - the biggest issue you have here is the difference in lighting between your scene and the one you are using as a reference.
The look of polished gold like this will largely depend on the lighting and the environment it is reflecting.
Given the context of the scene your canon is in - i’d say it looks pretty accurate and would be how I would expect gold to look under those lighting conditions and environment. Have you tried lighting it using different HDRI environments - perhaps using a studio lighting HDRI?
