The real invincibility glitch that people are using in PVP the one where you can shoot people from 1000yrds from under the map , involves going into co-op missions , playing 'the herd' , leaving pikes basin and riding through the railway tunnel to the last set of pilers , going through them on your horse , landing on top of the railway tunnel behind the barrier ,riding up the hill , jumping through a certain pair of trees , landing safely without falling into the river , then riding your horse to whatever town that features in the pvp games(aramdillo, chuparosa etc etc) then you have to hide your horse where no one will find it(thats why you see players who do it running out of the pvp area , then you get on your horse and hey presto you're under the map and able to kill players.