General principle
B/P rangers are almost always part of a B/P team consisting of several B/P rangers as well as other characters. The B/P ranger combines strong damage output from Barrage with high survivability due to his ranger skills as well as the meat shield created by the teams pets. The damage is usually further enhanced by spirits, necromancer orders, or occasionally elemental enchantment spells such as Conjure Frost.
The B/P team has its basis in several rangers using Barrage on a group of enemies, resulting in a very large amount of physical damage hits while the defensive side is enhanced by all B/P rangers bringing a pet. This is not used to inflict damage to the enemy, but to slow enemy groups down while they approach the rangers. The pets die frequently, but due to the damage output of the team, the enemies should die even faster than the pets. In a good working B/P team, mobs rarely reach the actual players; they die while fighting the pets. Even if the mobs reach the players, the ranger profession is blessed with some of the best survivability skills of the game, so that a break down of the meat wall need not spell disaster.
The ranger's pet was also often used as a source of corpses for the minion master's undead minions, which would serve as an additional meat wall to absorb damage for the group. After the November 13th, 2007 game update, pets no longer leave exploitable corpses.
 Side skills
That leaves 3 more skill slots. These are usually filled with survival skills, like Troll Unguent, Throw Dirt or a blocking stance. Additionally, most B/P rangers prefer to bring one or two of the ranger interrupt attacks for use against caster enemies.
Fast-moving, mobile Barrage/pet teams who do not wish to rely on casting nature rituals or orders will use enchantment spells such as Conjure Lightning to boost damage with similar damage output for less effort. Note that rangers must use an elemental bow string to receive the damage bonus in this manner, and this changes the damage type of the ranger to "elemental". This type of Barrage/pet team carries an extra ranger in lieu of an orders necromancer, and spends less time casting nature rituals resulting in more Barrages per second.
 Battle behavior
The B/P ranger is part of a team designed especially for high-end PvE areas. It combines a high damage output with several "safety lines" which prevent the team from wiping.
When approaching a mob of enemies, the rangers first lay down their spirits at a place where they can not be reached by the mobs. Then they send in their pets to attack the enemies. Once the mob starts fighting the pets, all rangers start using Barrage on the concentration of foes. While doing so, they are assisted by the necromancers orders. Single rangers might target especially dangerous foes to interrupt their skills. Once the group is killed, the rangers resurrect their pets and move on to the next group.
 Safety line 1: Meat shields
The first and always used safety line is the meat shield created by the pets (often, this is helped by a Minion master's minions). These serve to slow down the foes in the initial attack, preventing them from approaching the actual players.
 Safety line 2: Blind/block
If some enemies make it past the meat shields, the second safety line is activated: The rangers use their skill Throw Dirt to blind the foes, thus drastically reducing the damage taken. This can be further reduced by blocking stances. Blind can not be kept up on all foes for a prolonged time, but the short frame should usually be enough to kill whoever made it to the ranger line. Any monks and necromancers are placed behind the ranger line, such that they are still relatively safe as long as the rangers are engaging the foes.
 Safety line 3: Run&res
Should the time bought by blinding the enemies still not be enough to kill the enemies or should a foe have made it to the squishy backline, party members will drop quickly. In that case, the surviving rangers can make a break for it and outrun the enemy mob till all foes have lost aggro. Then the rangers use their hard res skill to resurrect the remainder of the team.
Since the B/P team is a very specialized PvE build, it is hardly ever used in PvP. The build depends on exploiting the AI via meat shield and usage of AoE damage. Humans will not be as easily fooled, making this build very easy to counter and thus unused in PvP.
The B/P build comes close to being perfect for the areas it is developed for. However, being a very specialized build, the need to form a group of people with perfectly matched skills is a disadvantage, taking more time than simple pick up groups. The team also depends on each team member fulfilling the role described by the build - mistakes by an individual are harder to compensate for.
The B/P team works well in areas with big groups of foes that are heavy in melee fighters; however, it loses much of its effectiveness against pure caster groups. Finally, a single B/P ranger is still a semi-useful build when played in normal (non-B/P) groups, but then the 2 skill slots used for the pet are mostly wasted.