For those who want to print RedCowls fantastic xshot-longshot-half-dart-magwells but don't want to sacrifice the original magwell internals.
Simply print the slide and two of the locks, put in a spring (I took a spring of a broken pen and cut it in half), then install them to your magwell and screw the parts together with some spare nerf-screws.
(I only used them in the flared magwell, but it should be working in the low profile version without issues.)
The author marked this model as their own original creation.