FWIW - I've used the OSS string carry since the 1980's, w/o dropping a gun either down my pants leg or out of my belt line, because I adjusted the loop & cord lengths appropriately to the size of the gun I was carrying at the time.
To "make" one:
From about a 12" length of paracord, bootlace, rawhide (whatever), tie a 2" loop into each end and thread the pants belt through the loops with the center section of the cord "up".
Fold the "up" section "down" inside the pants waistline behind the belt & insert the handgun's barrel or slide into the resulting inside loop. An instant IWB holster.
The cord will stop a revolver from dropping down the pants leg via bearing against the cylinder face; an autoloader via bearing against the face of the trigger guard and/or various side levers.
The end loop size(s) can be adjusted for different belt widths; the middle cord length adjusted for handguns of different thickness'.
This is with my Walther PP, but a slightly bigger loop span works just as good with my much larger/wider/heavier Charter .44 BullDog.
.