I realise that the laser would be mounted to avoid interference with using the open sights (perhaps barrel mounted?) but I meant interference with the actually aiming point. I don't kow how big the laser 'dot' would be on the target (the high power compact trade lasers I've seen produce a fairly small dot at 25yds) but if you lined up the open sights to take a shot, wouldn't the front sight obscure the laser 'dot' on the target - I mean they are both directed at the same point and I suspect that the size of the front sight on the target would be greater than the size of the laser 'dot' on the target. Either the open sights would need to be set low or the laser would need to be set high to avoid interference and so you could se the dot.

This isn't a problem with a scope because the cross hairs would generally be finer than the laser 'dot' and you can still see the laser 'dot - so assault rifle with optics are not a problem.