What’d the meaning of bullet markings?
Swedish tracer, 9 mm sk ptr m/68 Slprj
Quoting Chris (The Swedish military ammunition site)
“The early form of m/68. It is made in Sweden. Live round m/68 is used for 9mm practice weapon for Pskott m/68. It is used for a distance up to 200 meters. The ammunition is weaker loaded than a standard round, and is forbidden to be used in submachine guns. If fired in a pistol the weak load will make the gun to not cycle.”
In other words, it’s trajectory matched to the Pskott m/68 (“Miniman” disposable AT launcher).
Newer types of this ammo is used in sub-cal trainers of the M72 and AT4 (M136).
The combination of weak load and very short barrel for the sub-cal trainer means these can get stuck in longer barrels.