What kind of scale are you using to weigh out 0.0025g?
I imagine
@Sparkpug meant
25mg rather than 2.5mg: that would be 0.025g, i.e. about a 40th of a gram—I use something like that in my OG E-Nano to very good effect.
I have a cheap digital scale that verifies that weight to some extent, but probably isn't very accurate at those levels. I base my own weight estimates on numerous different checks I've made over the past few years, looking at consumption, number of hits gotten per gram, etc. I really load more by volume than by weight, but all the checks I've done seem to agree that the weight is in that range. (I usually load about 2/3 to 3/4 of a screen, oriented in the much-maligned cup style
), then very lightly tamp my (usually fluffy) fine grind down to about 1/2 a screen (or "bowl", so to speak, esp. since cup-style).
For me, at least, 2.5mg would be about the size of a BB pellet, maybe less. (Hmm, perhaps I should try it out anyway: my experience is that whenever I reduce the load, lower the temp, or slow down the temp increase, I get as good or better flavor & effects … against all logic and rationality … so who knows? Thus my apologies to
@Sparkpug if the 2.5mg was intended as that.)