This magazine is a staggered box magazine with a formed steel body and feed lips. It also has a polymer base plate and shoulder. The mag is compatible with your Browning AB3 rifles.
Specifications:

Caliber	30-06 Springfield
Capacity	4 rd
Finish	Black
Model	Browning A-Bolt III
Material	Steel
Type	Detachable
Model Fit	AB3
Brand Fit	Browning
Max Capacity	4