Mine wont crumble, it will bend not snap.
I have several mixes I like. The one that really is above the others is one with a high consontrate mix of peanut oil and a hard deer tallow I make. But you can't over heat it when you melt it down.
And I most likely make the lube differently than most will.
When I make my lube I use a deep fryer with about a quart of water in it and I add the wax and oil or what ever and let it simmer with the lid on the pot to keep most of the water in the pot.
This will blend the components better I feel and it will add moisture to the lube.
When the lube cools it will be a hard cake and I scrape the gel off the bottom and remelt it to make lube blocks and wrap them with cling wrap for later use.
I dont like a hard lube. My lube you can push a bullet out of the lube block with ease using your thumb with out it hurting.