Yes, a way to denote constriction. But I guess the questions would be better phrased as "When a scattergun is marked "Not For Ball", etc.....

Not for Ball
Non Pour Balle
Nem Golyonak
Jen Pro Broky
Nicht Fr Kugel

it meant that the tube experienced proof with shot and not a solid projectile. The Austrians were the only ones that continued to subject their scattergun tubes to a solid projectile w/ "windage" while all other proof facilities employed shot.

Cheers,

Raimey
rse