HK Bolt carrier hash marks

[dluch]

Does anyone know what are those vertical grooves on the bolt carrier for?!

[G3Kurz]

Does anyone know what are those vertical grooves on the bolt carrier for?!

Poor man's forward assist (seriously!)
Push forward with your thumb or a pointed implement to fully seat the bolt group.
G3Kurz

[dluch]

I originally thot so, but couldn't imagine doing that without Herculean Man-Thumb strength.. maybe those Germans ARE superior to the rest of us afterall!

[wh]

Let your bolt go forward slowly so that it does not close all the way. It does not take much force to close it with your thumb. You can use this method when you don't want to make a lot of noise before your first shot.