I don't get excited until at least 5 years after a cartridge is introduced by a major manufacturer. Keep in mind that major manufacturers are making ammo, right now, for calibers such as 221 Remington Fireball, 260 Remington, 280 Remington, 30 Remington, 9.3x74Rimmed and others. None of these are any great sellers compared to 5.56x45, 7.62x51, etc.
I know that .300 BLK was a requested experiment, initially, that was marketed properly by AAC, et al.
But, one of the reasons I posted the "Buy 223 now" thread was because I have heard quite a bit of rumbling about the military wanting to go to a new caliber/ammunition type in the future.
I have mixed opinions about the military changing drastically, especially when you're talking about a major change in the
type of ammo (caseless, plastic-cased, etc.).
IF it happens, then I'd suggest that we're looking at a major increase in the price of cased .223/5.56x45 and 7.62x51 ammo since much of the benefits of massive productions amounts trickled down to we, the shooters.
I could go all TFHB on the discussion and suggest that the Military (and, soon after, LE) would change to a new ammo type that is prohibitively expensive to the average shooter. It would be so much easier to simply "turn off" manufacturing, at some point, and let supplies dwindle. Of course, the panic purchasing of the last 10 years or so would mean that some would have ammo for a very LOONG time. But, in 20 or so years?
Here's an interesting read, not 100% on-topic, since it's geared more towards the .300 BLK, but it helps explain some of the mindset behind caliber/ammo selection by the military:
http://smallwarsjournal.com/index.php/jrnl/art/the-infantrymans-half-kilometer-reconsideredAs to the .224 Valkyrie, I just don't see much of a military market for the advantages the bullet offers beyond Long Range Shooting, which I consider a comparatively tiny market share.
But, I have been wrong in the past. After all, I predicted Hillary would be in the White House right now.
The Professor