On Feb 23, 12:38 pm, cavelamb himself wrote:
Mike Henry wrote:

You might be able to find 100 mL disposable syringes if you need to add
an exact amount in that range to keep the weight consistent.
Becton-Dickinson is one maker, but we usually get such things from a
scientific supply house like Fisher Scientific or VWR. Farm supply
stores might also sell them.

Mike

Or vetenarian supply.

I get mine from Tractor Supply...

Ever thought of doing it by weight? Use a digital scale, re-tare after
each use. Determine what the weight of 100cc is and add until you
reach that weight.