Any idea about this red stripe meaning?
Looks like someone’s home-made dummy cartridges, marked with red fingernail polish.
From the way some of the projectiles appear to be pushed in, these have likely been cycled through a handgun repeatedly.
Obviously a Bubba job.
Proper Drill/ Dummies would have a Sand fill ( or wood) and a good taper crimp to hold the bullet steady and a Rubber or Leather or Tough Plastic as a Primer Pocket Filler.
This omission will go a quick way to firing pin fracture ( dry firing on empty pocket)
AVB Film Guns.
These are not dummies for ‘dry firing’, they are home-made Action Proving Rounds, used to make sure the pistol will feed from the magazine, chamber the round, and eject properly. There is no primer to ID as an inert round.
Here is a box of 9mm from Winchester/Olin for an example, note there is no flash hole, and the primer pocket is empty.
This is a full box, and I have more somewhere. When I find them I will pull the bullet and let you know what I find.
Many factory dummy rounds, made for trade shows, or for function testing, do not have primers or any other filling of the primer cup. Winchester eventually eliminated even the primer cup itself, with their functional dummies having a flat base.
An inside spacer of some sort of another is good to have in dummy rounds as it prolongs their useful life tremendously. Some “quickie” dummy rounds made to try to figure out a feeding problem on a one-time basis, usually home made (I have made some in the past for that purpose) don’t really have to have a spacer. They generally, if properly crimped, last long enough for their intended purpose. “Show” dummies, be it for a trade show, to fill cartridge belt loops for safe display, or the like, don’t need a spacer. Primer cup fill is only necessary for dummy rounds made specifically as snap caps. Of course, some snap caps can be used for all the reasons dummy rounds are made, and then should have spacers and a filling of the primer pocket conducive to use without damaging firing pins.