I just picked up a Glock 21 SF and I am looking to trade for some additional magazines. If you have 2 *NEW* Glock 21 magazines I can trade you two new Glock 17 magazines or 100 rounds of Federal .223 ammo. If you have two used Glock 21 magazines I can trade you two used Glock 17 magazines. If you happen to have some for sale at a decent price feel free to send me a PM. Thanks!