Problem while texture painting on a texture

Hi! (this is my first post here so excuse me if I post in the wrong place or smth)

So I have been working on a model of a rail gun as a test for a game engine I am developing.
When I got to texturing I noticed something. The texture painting seems to be broken on the edge of an uv island. (red painted section)
Notice how the background of the texture is bleeding into the supposedly totally filled island.
I am using 512x512 texture and it is as large I am willing to go. (as the model needs to be rendered in real time)

Note: this is not a problem of blending because even on closest neighbour blending mode it is a little bit better but is still there.

Could I fix this by somehow giving the islands a pixel or 2 of a margin for painting?