If one can manage it, it might also be worth practicing using the Gravity Gun as a grenade launcher to extend the distance of his grenades.

The MP7's secondary fire and Resistance RPG rockets are also ideal and can substitute for grenades.

Closing the cap can prove to be painful due to the projectile speed of the sniper rifle, sprinting while strafing will increase the likelihood for snipers to miss their shots. This can be easier said than done, however, because if the sniper spots the player before they're within range, which is often the case, they'll have to avoid his fire to get close enough. Explosives are a different matter, however, and if the player can get close enough, a hand grenade will blow the sniper out of his hole nicely. Snipers usually set up in well fortified 'nests', effectively invulnerable to ordinary gunfire. Snipers seem to take the doctrine 'shoot anything that moves' quite literally, shooting at any living creature (except allied Combine forces), such as birds, and even signs. They will also shoot breakable objects to limit the amount of cover the target can use. However, even in Easy mode snipers will take leading shots(shooting to the direction the target is supposed to go) and in Hard, they almost have a guaranteed hit, and will take you down in 2-3 shots without armor. The round travels so much slower than other bullets that sidestepping the shot is quite easy at long range. However, it is possible to confuse the sniper by running in one direction until he fires, then suddenly changing direction, then repeating the same process again until they reach cover. Snipers are very accurate, and will fire ahead of any moving target so the pulse from the rifle hits them dead on.

Half life 2 counter sniper