Drilled out some more holes and made another batch of about 30 darts.
Is everyone using a paint stir stick to poke the oogoo into the holes? I prefer using my fingers... or if possible, a plastic-coated wooden rod about the same diameter as the tip diameter. Makes sure you get the oogoo all the way in, and it's pretty quick. Then smear some more over and repeat.
The amount of cornstarch may also affect the smell... if it acts as a catalyst, more vinegar smell is generated, and it's generated faster.
Edit: On felt: You should be looking for felt that does NOT fall apart easily - fluffy felt makes bumpy/unbalanced dart heads.
Darksircam: Thanks for helping to keep this concept alive!
With a solid piece form I did have some difficulty getting the air pockets out, and the form filled, about 1 of 20 heads were defective because of that. With a 2 piece form - It's much easier because air can escape between the boards as oogoo is pushed in.
The instructables site suggests wrapping anything you want to use as a spatula in "Gorilla tape" (gorilla [same brand as gorilla glue]brand duct tape. Cured oogoo will peel off easily from that stuff.
My experiment of "outsourcing" dart production to my sister is going well. She's had a 1 or 2 batch learning curve (first batch the backing felt wasn't pressed into the oogoo enough, so there was a poor bond to the felt), But I'm now confidant that anyone with a form and the patience can make these.
I've slapped a PTEG'd 7.5" RF20 turret onto a big salvo. I don't know what ranges are compared to slugs, but the 20 shots I took (minus the few from a belligerent tank) averaged 75'. The max was 99, min was 54'. That is a pretty big spread, not sure why, though I suspect turret seal issues. I don't know how slugs would compare, but I'm at least hitting war worthy ranges with these darts.