Skeet doubles is shot in rounds of 50 targets instead of 25. These 50 targets are made up of two “part rounds” - the first part of the round containing 24 targets and the second part of the round containing 26 targets.

other than that the principles are the same as National skeet.                                                                                                                                              Illustration by clay-shooting.com 

TECHNICAL RULES
FOR
SKEET DOUBLES
These Rules replace their equivalent numbers in the preceding Rules for English Skeet when shooting the
discipline of Skeet Doubles. All other Rules are common to both disciplines.
4.90 The competition will be shot in rounds of fifty targets in the following sequence:
First part of the round (24 targets)
Station 1      One (1) double high house first
Station 2 One (1) double “
Station 3 One (1) double “
Station 4 One (1) double “
Station 5 One (1) double low house first
Station 6 One (1) double “
Station 7 One (1) double “
Station 6 One (1) double “
Station 5 One (1) double “
Station 4 One (1) double “
Station 3 One (1) double high house first
Station 2 One (1) double “
Second part of the round (26 targets)
Station 1      One (1) double high house first
Station 2 One (1) double “
Station 3 One (1) double “
Station 4 One (1) double “
Station 5 One (1) double low house first
Station 6 One (1) double “
Station 7 One (1) double “
Station 6 One (1) double “
Station 5 One (1) double “
Station 4 One (1) double “
Station 3 One (1) double high house first
Station 2 One (1) double “
Station 1      One (1) double “
4.91   These two “part rounds” may be shot on different layouts in the above order.
4.92 There are no optional targets in Skeet Doubles.
4.93 Competitions will be shot in multiples of fifty targets, as per the sequence described above.