.300wm caliber 3.715" mag length 3 round capacity Weighs 5.5 ounces Heat treated and coated with Teflon for maximum durability Max OAL 3.615" This .300 win mag magazine can also be used for .338 win mag, 7mm rem mag, .280AI, 26 & 28 Nosler and .375Ruger parent cased rounds. In some cases the feed lips may need to be bent inward or outward to set rounds at the correct height to feed.