Military shotgun Flechetts loads were loaded with half of them stacked in backward.
This allowed getting more in the shell, since the tiny fins took up room.
By reversing half, the shell could be completely filled.
The problem with this is, the Flechetts that were backward often failed to stabilize.
Even the point forward darts often failed to stabilize, and darts were often found simply sticking in the surface of targets, or hitting sideways.
The military experiments with Flechetts in shotguns were a failure.
The needle-like darts have almost no mass and therefore have no "stopping" or shocking power.
Too many darts failed to penetrate, and this lessened the effect even more.
There were too many instances of enemy troops getting center-mass hits who weren't stopped, and continued attacking until they bled to death internally.
The Flechetts were often fatal......eventually.
The problem with this is, due to the short effective range and the inability to quickly stop someone, "eventually" wasn't soon enough, and the user was in real danger of being killed by a "dead man".
Bottom line: Flechetts were effective when used in howitzers as "bee-hive" rounds for close defense during attacks, but were a failure in shotguns.
For this reason, the Flechetts shotgun round was dropped by the military as one of those "good ideas" that failed in the real world.
To date, no shotgun round yet discovered is more effective than standard old-fashioned, low-tech lead buckshot.