Various AR Springs, Buffers, and Receiver Extensions/Carbine Buffer Tubes

From top to bottom:

Unknown brand A2 rifle length buffer and buffer spring
Norinco CQ311 rifle length buffer and buffer spring
AR Stoner standard AR carbine buffer and buffer spring
DPMS A2 rifle length buffer and buffer spring
AR Stoner AR308 A2 rifle length buffer and buffer spring
BCL102 carbine length buffer and buffer spring

 

From top to bottom:

BCL102 carbine buffer tube

AR Stoner standard AR carbine buffer tube

Norinco CQ311 A2 rifle length receiver extension (overall dimensions identical to standard US A2 rifle length receiver extension, except threads re metric and requires a metric 13mm wrench instead of an imperial size wrench.