Added venting to gas piston tube, slight edits to specular exponent and definition on diffuse texture.

Edits to specular exponent for metallic effect; metal now appears more 'satin' in appearance due to microabrasions and pitting. Plastic magazine has different specular term.

Changed style to Gunsmith; fits intended style of the weapon better than the previous transparency 'hack' which looked extremely pixellated in low detail settings.

Slight edits to texture contrast, darkening of paint on dustcover and steel parts, fixes to buttstock transition.