Kraschenbirn
04-15-2007, 07:01 PM
Cast some boolits this afternoon from a used Lyman #375248 that I recently acquired off fleaBay and got some "interesting" results. Now, my Lyman Cast Bullets Handbook shows that the #375248 drops boolits of 249 gr. from #2 Alloy which should, from my experience, yield PB boolits should running slightly heavier...say between 3%-4%. Not this one, though. Casting from the same 25-1 mix I use for my BP 45-70s, this mould drops boolits of around 245 gr.
I say "around" because boolits from one cavity run 7/10 gr heavier than the other...244.5 gr average (SD .2 gr after culling for visible defects) and 245.2 gr. average (also .2 gr SD) from the other.
At first, I thought it might've been something I was doing so I ran off 25 casts filling the front cavity first and then the rear. Then, I ran another 25 casts reversing the process. Absolutely no difference in the dropped weights!! Also tried casting a few at a slightly higher temp...same results.
Boolits from both cavities measure .379-3795 and appear fully filled-out with sharp edges on lube grooves and base: sprue plate is flat and fits flush across top of blocks, and the blocks, themselves also appears flat and true. (Haven't got a surface plate to actually measure "flatness" but using a machinist's rule and the ol' MK 1 eyeball, they look good to me.) And, before anyone asks, I DID verify my scale calibration using check weights.
Anybody else ever run across something like this?
Bill
I say "around" because boolits from one cavity run 7/10 gr heavier than the other...244.5 gr average (SD .2 gr after culling for visible defects) and 245.2 gr. average (also .2 gr SD) from the other.
At first, I thought it might've been something I was doing so I ran off 25 casts filling the front cavity first and then the rear. Then, I ran another 25 casts reversing the process. Absolutely no difference in the dropped weights!! Also tried casting a few at a slightly higher temp...same results.
Boolits from both cavities measure .379-3795 and appear fully filled-out with sharp edges on lube grooves and base: sprue plate is flat and fits flush across top of blocks, and the blocks, themselves also appears flat and true. (Haven't got a surface plate to actually measure "flatness" but using a machinist's rule and the ol' MK 1 eyeball, they look good to me.) And, before anyone asks, I DID verify my scale calibration using check weights.
Anybody else ever run across something like this?
Bill