If cost is a concern, then just using off-the-shelf bearing balls is almost certainly a good choice. They’re mass-produced in such volume that I doubt you can find cheaper small hardened steel objects with reasonable drag properties
Those look some of the extremely common 4-5mm hardened steel bearings. All of them in that grenade are likely less than 1 euro. Looks like they are embedded in resin. The resin likely cost as much.
If cost is a concern, then just using off-the-shelf bearing balls is almost certainly a good choice. They’re mass-produced in such volume that I doubt you can find cheaper small hardened steel objects with reasonable drag properties
Those look some of the extremely common 4-5mm hardened steel bearings. All of them in that grenade are likely less than 1 euro. Looks like they are embedded in resin. The resin likely cost as much.