The mold was made at a local sheet metal shop. I chose stainless (and apparently a high grade at that - no rust yet !
) for two reasons : to get the guy to do it and also to support American manufacturing - since I saw the guy make it, I know that the money was going to the local economy and not a communist nation, even though the mold itself was $70 dollars.
There's probably nothing wrong with Tupperware, but I am a bit hesistant to place two blocks end-to-end, at least before 12" of penetration depth. I think that as a bullet approaches the back of the block, say a half inch before exiting, that the toughness of the block is reduced since the only material behind the back side of the block is air, which is of course much less dense than the gelatin. This might effect results, but I have never seen anything to support this.
Can I ask the motivation/usage for the .22WMR testing? That sounds very cool.
Where did you get your mold? I was thinking about using several Tupperware containers as molds, but would much rather have something similar to the 16x6x6 that most people use. Also, did you say you paid $70 for the mold, or for the gelatin?
I dont think I will be testing any rifle bullets except for maybe some .223, but mostly .22LR, .22WMR, 9mm, and .38 special.