MDT metal magazines are manufactured from high strength steel, and finished with Cerakote for ultimate durability. This magazine can also be used for 7mm, 30.06 and 6.5x55 calibers. Feed lips may need to be adjusted. The magazines are manufactured in multiple lengths. All our chassis are manufactured with a 3.715 magazine well. If however you purchased a rifle direct from an OEM or retailer, please check the specifications, as it may be 3.775. For Tikka T3 long calibers in our chassis you must use the 3.560 option.