Admiral Beckett Brass — ruling 1

Admiral Beckett Brass's triggered ability checks what happened earlier in the turn. It doesn't care whether Admiral Beckett Brass was on the battlefield when those Pirates dealt combat damage, whether those creatures are still on the battlefield, or whether they're still Pirates.

Admiral Beckett Brass — ruling 2

If one Pirate deals combat damage multiple times, most likely because it has double strike, it counts as only one of the three Pirates for Admiral Beckett Brass's triggered ability.

Admiral Beckett Brass — ruling 3

If more than one player was dealt combat damage by three Pirates, you target only one permanent. It may be controlled by either of those players.

Admiral Beckett Brass — ruling 4

The control-change effect of Admiral Beckett Brass's triggered ability lasts indefinitely. It doesn't wear off during the cleanup step or when you lose control of Admiral Beckett Brass.

Admiral Beckett Brass — ruling 5

In a multiplayer game, if a player leaves the game, all cards that player owns leave as well, and any effects that give the player control of permanents immediately end.

Admiral Beckett Brass — ruling 6

In a Two-Headed Giant game, combat damage dealt by Pirates your teammate controls will count when checking for Admiral Beckett Brass's ability.

Admiral Beckett Brass : règles, fonctionnement et interactions (MTG)

Admiral Beckett Brass is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Other Pirates you control get +1/+1. At the beginning of your end step, gain control of target nonland permanent controlled by a player who was dealt combat damage by three or more Pirates this turn.

How it works : Admiral Beckett Brass

Original English text — Wizards of the Coast / Scryfall

#1September 29, 2017· Wizards of the Coast
Admiral Beckett Brass's triggered ability checks what happened earlier in the turn. It doesn't care whether Admiral Beckett Brass was on the battlefield when those Pirates dealt combat damage, whether those creatures are still on the battlefield, or whether they're still Pirates.
No other card is named in this ruling.
#2September 29, 2017· Wizards of the Coast
If one Pirate deals combat damage multiple times, most likely because it has double strike, it counts as only one of the three Pirates for Admiral Beckett Brass's triggered ability.
No other card is named in this ruling.
#3September 29, 2017· Wizards of the Coast
If more than one player was dealt combat damage by three Pirates, you target only one permanent. It may be controlled by either of those players.
No other card is named in this ruling.
#4September 29, 2017· Wizards of the Coast
The control-change effect of Admiral Beckett Brass's triggered ability lasts indefinitely. It doesn't wear off during the cleanup step or when you lose control of Admiral Beckett Brass.
No other card is named in this ruling.
#5September 29, 2017· Wizards of the Coast
In a multiplayer game, if a player leaves the game, all cards that player owns leave as well, and any effects that give the player control of permanents immediately end.
No other card is named in this ruling.
#6September 29, 2017· Wizards of the Coast
In a Two-Headed Giant game, combat damage dealt by Pirates your teammate controls will count when checking for Admiral Beckett Brass's ability.
No other card is named in this ruling.

Interactions with other cards

These cards' text mentions Admiral Beckett Brass.

Brazen Boarding

Brazen Boarding deals 4 damage to target creature or planeswalker. If excess damage is dealt this way, conjure a card with mana value equal to that excess damage from Brazen Boarding's spellbook onto the battlefield. If that excess damage is 4 or greater, instead conjure a card named Admiral Beckett Brass onto the battlefield.