if the correlation in weight to the blunt is the issue, and it sounds like you lose blunts as quick as i do,
i converted to using pistol cases a long time ago.
the 38spl case or the 357mag cases fit the 11/32 shafts very nicely.
i snip off small pieces of lead off a fishing weight with the case on a grain scale, until it hits 125gr, then i wait for my wife to leave on an errand, put the lead in the case, and stand the case upright on the electric stove element, only takes a few minutes, to melt all the lead into the front of the case.
they are tough, extremely durable, and very cheap!!
but if you need more length to be able to add more weight you could consider longer cases-
38spl - 1.155"
357 mag- 1.29"
357 maximum - 1.605"
38x55 winchester - 2.085"
then again, the tuffheads have a very good rep!
, living up to their name!