This drum replacement or spare magazine is compatible with your AR-308 using LR-308 (DPMS) or SR-25 pattern magazines. It is constructed of DuPont Zytel polymer with injection molded mag follower and stainless steel mag spring. Made in the USA.
Specifications:

Caliber	308 Winchester/7.62 NATO
Capacity	50
Finish	Black
Model	AR-308
Material	Steel/Polymer
Type	Drum
Model Fit	AR-308
Brand Fit	AR-10 Platform
Max Capacity	50