You can take the tip of a round and push down on the detent, on the front sight and twist the sight post, in the direction, that you need to go.
I personaly like the front sight tool. You just need to make sure it's the right one. Some tools are just for A1 sights and some are for A2 sights, I have one that has both on it.
The A1 front sight post is round, while the A2 front sight post is square.
I hope this helps ya.