Artillery Grip strap Markings

[Navy]

Gents,
If I may offer an alternative solution.
First of all, Jaeger units were not reserve formations, as I understand the German order of battle (I may be dead wrong and will take the hit if so).
Second, the Germanic J= the English I. So, I would posit this as a Reserve INFANTRY regiment piece.
My zwei pfennigs.
Tom A.