I completely agree with Bramble.

I've made millions of parts. By far almost all (by percentage) of them were on big-dollar high-tech equipment, in concert with high-buck, high profile businesses.

I have also ventured to do short production runs of special items, but you have to have your immediate market nailed and be prepared to do it as a favor for the community you're serving the product to as profit will likely be pretty slim to none. Prepare yourself for wages below minimum wage on little jobs like this express rifle sight idea.

There's good reason that from period to period, the express sights from neighboring gun and rifle makers looked awfully similar.

--Tinker