Strike Industries Strike Magwell, For Glock 17/22/31/34/35 Gen 4, Polymer, Black SI-G4-MAGWELL-17 The Strike Industries GEN4 Magwell was designed to provide easier reloading of the magazine while adding SI styling. Keeping to the slender factory design of the pistol grip" the benefit of adding a funnel-like magwell to help prevent the dreaded reload bobble outweighs the added material of this G4 Magwell.