If you're worried about it, the best time to jump on is right now. I used to worry about the same thing, but honestly it's new, some people are excited about it, and BlackJack has loads of pills right now (and orders in for more). If supply dries up in a year or two, then you probably have used up a good chunk of barrel life (with the way a lot of us shoot) so it's not a pain getting a new tube for a 6 or 6.5 flavor.
Take it a year or two at a time if you want, but I don't see BlackJack going anywhere soon. They've hit goals in 8 months that they had laid out in their five year plan. I've said it before, but they had all the pieces in place for a good launch BEFORE launch. They've had multiple barrel makers and reamer producers on board from the beginning and they're picking up more every month it seems like. Their growth has been astounding.
This is all without considering the cult following that 25 cal gathers. If sales aren't big after a while, I predict they'll be consistent at least. There's been a lot of people waiting for someone to do this for a while. It should be enough to keep a smaller company like BlackJack afloat.
Until that time, grab a barrel and shoot the lowest form-factor jacketed bullet on the market.
As for big manufacturers jumping on, I'm not really sure. Maybe they want their own slice of the market, but 25 cal shooters make up a fraction of shooters compared to 6 or 6.5 or even 30 cal. It may not be a big enough niche to support more than one company effectively and so the big guys might stay out of it because they don't think there's enough there for them.
BlackJack has future plans, so they don't see themselves going anywhere. A "hunting" bullet releasing this year and a design in their back pocket that Miles really wants to bring to market (it's heavy!). Take that how you will.
