Honestly? no. I don't think Hahn is in error or mis-labeled. I think it really is 344 but I was more curious as to the paper making/coating technique that would allow them to shave 24gsm off the product while leaving the thickness the same. They must have manipulated the density *somehow* (possible lightweight 'filler'? thicker coating and thinner base?).
But now that you mention it, I think I will use my lab balance and see.
<time passes>
very odd. So the balance says 2 sheets of inked paper (profile charts) weighs 37.62g and is 2x 8.5x11 (=187sq in -> 0.1206 sq m)
If I take off 1.0-1.25g for each sheet's worth of ink (I have no spare <13x19 right now), I get 291gsm (37.62-(2*1.25))/0.1206
Obviously will have to repeat this w/ blank sheets since I'm SWAGing the ink total.
Of course, now the wife thinks I'm more insane than I normally am for weighing paper.
Edit: Even using the RedRiver #s, I can't get it to 'near' 344