Abstract: The present disclosure provides apparatus and methods for coupling an item to another item. The apparatus comprises a coupler mounted on the item and comprising a mating face having a plurality of catches thereon, the plurality of catches comprising at least one complementary pair of catches positioned and shaped to be engaged with corresponding catches of another coupler having an identical mating face when mating faces of two couplers are facewise engaged with and rotated relative to each other to align with each other. The coupler may be implemented as a floor plate of a magazine, as a clip, or in other forms.

Abstract: The present disclosure provides apparatus for coupling an item to another item. The apparatus comprises a coupler mounted on the item and comprising a mating face having a plurality of catches thereon, the plurality of catches comprising at least one complementary pair of catches positioned and shaped to be engaged with corresponding catches of another coupler having an identical mating face when mating faces of two couplers are facewise engaged with and rotated relative to each other to align with each other. The coupler may be implemented as a floor plate of a magazine, as a clip, or in other forms.

Abstract: A spring comprises a continuous wire member formed into a plurality of coils along a central axis. Each of the plurality of coils comprises a plurality of straight portions extending between bend portions each extending from one of the straight portions. The plurality of coils form a first spring body and a second spring body, each spring body comprising at least three coils and having a first end and a second end with the first end of the second spring body connected to the second end of the first spring body.