Normal mapping in blender

Not sure if this is the appropriate place to ask for assistance, apologies if it's not.

So here's my problem; I'm trying to normal map the shotgun model following every tutorial on how to normal map in blender. The low poly model is one mesh object, the high poly version is made up of many separate mesh objects. Following the normal mapping tutorials results in disruptive grain and also the maps of other objects that do not occupy the same 3D space appearing on maps of unassociated UV islands. When I use the same techinique on something simpler, for example a cube with cylinders in its projecting from its faces, it results in a pretty good normal map. This same problem occurs when I try to map the diffuse texture of the high-poly shotugn onto the low-poly shotgun. Increasing the bias to 0.001 reduces this effect but does not eliminate it.

Any idea why this happens?

Hmm, screenshots would probably explain it better, but I am also no expert with this.

I guess you should rather ask this on the blenderartists board.

Hmm, maybe if you can try to "explode" the mesh like described here:
http://joeyspijkers.com/t_normalmapping.html

Also not sure if that is part of the problem, but moving mirrored uv islands by "1" in the uv space helps with baking those a lot.

I've been trying to upload the blend both here and on blenderartists, but for some reason, it had not failed to go through when i made both threads. here's the blend, the high-poly version is on layer 2.

  shotgun_12.blend.zip (Size: 4.12 MB / Downloads: 5)

Hmm, maybe if you can try to "explode" the mesh like described here:
http://joeyspijkers.com/t_normalmapping.html

This technique worked like a charm, thanks for the post!

Glad that I could help out. The model looks great btw.