1) Enter a game and select a weapon that has good crosshair sights, such as one of the trooper weapons.
2) Bring it in to the aim and mark the aiming point with a small dab of tipp-ex (aka correction fluid, you know the white stuff for paper..) Now colour in that white dot with a red pen. 
3) Voila, permanent sights for any weapon!
Please make sure you use tippex and not just a permanent pen, its much easier to scrape off
I am not liable for any damages to your equpiment caused while doing this by anyone stoopid enough to think its a good idea!
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