Ooh, that's a cool idea! As far as I can tell, it should neatly sidestep (at least some of) the toxicity issue with eating caragana seeds. The one toxin I'm aware of in these is canavanin, a non-proteinogenic amino acid, and since it's water soluble I imagine not that much of it would end up in the oil? Maybe?
Douglas Alpenstock wrote:One thing is certain: the pods are tiny and it will take a lot of pods and a lot of labour to gather an appreciable amount of seed for oil. I wonder, can you gather them in a late green stage (easier to handle) rather than ripe seed (exploding from pods), for pressing?
In my experience, they don't shatter so much until they dry, so if there's a rainy day after ripening but before natural shattering, you can gather them all then and dry them indoors on a screen, maybe with a cloth on top to stop the seeds from escaping. Around here (Scandinavia) the seed pods often stay whole until late winter or early spring, but that might be because our climate is a lot more humid than in the native range of caragana.
You certainly would need a lot of seeds to get a good amount of oil, though. Plants For A Future claims that the oil content is about 12%, so way lower than hazelnuts for instance. Still, if you have a lot of bushes, I can totally see that it'd be worthwhile. Do tell us how it goes!