L -> R USGI 30-rounder (1005-00-921-5004) with orange Magpul follower; Magpul PMAG 30 Gen M2 (1005-01-576-5159); Magpul PMAG 30 Gen M3 (1005-01-615-5169).
It amuses me they all have NSN's but at present none are approved for issue. My (formerly) green follower USGI has been replaced by the tan follower 1005-10-561-7200 which itself will be replaced by the tan bodied, blue follower 1005-01-630-9508.
They all hold 30 rounds of 5.56x45mm.
They are within an ounce of each other in weight.
With 30 rounds of M855 the USGI is 1 lb. 0.7 oz., Gen M2 is 1 lb. 1.8 oz., and Gen M3 is 1 lb. 1.7 oz.
I also need to plug the Magula Ltd. StripLULA 10-round loader and unloader. It really made moving ammo from one magazine to the other for weighing simple and easy. Also, it's nice that it can load magazines with loose ammo.