The round is supposed to offer similar ballistics to the 7.62 x 39mm used by the ak-47. Compared to the majority of rifle rounds, it does not have an extreme taper which aac claims leads to better cycling (fewer failures during feeding and ejecting).
The cartridge will work with the existing ar-15 lower specs...meaning you just swap an upper and you're good to go. AAC is selling a 16" and a 9" (SBR) upper. You don't need a proprietary magwell block like with an ar-15 converted to 9mm or .45. They claim it has low recoil (I guess it's all relative) and that the additional weight of the bullet makes it better suited to penetrate barriers.
One of the more interesting features is the ability to load subsonic rounds. I haven't seen any SPL numbers, but it should be significantly quieter than a 5.56x45 with a proper suppressor. This article claims it's quieter than a suppressed 9mm (subsonic), but I have yet to see anything that corroborates that claim. The best part is that AAC isn't trying retain licensing from the round, it's completely open....so anyone can manufacture ammunition and parts.
Anyway...interesting concept. I think it will most likely be a hobbyists' modification. Still very cool.
Interesting. I've looked for info on the 7.62x40 before, this looks like the same idea as that, .300 whisper, etc.
I prefer heavier bullets, so this appeals to me over the 5.56 platform.
Funny that you bring that up...the blog that I read this on brought up the whisper cartridge as well. The author seems to think that licensing was the major limiting force in its adoption....however some of the posts below point out that similar claims were made of the grendel cartridge when in fact the licensing costs are minimal. Maybe the mere concept of having to license (or deal with lawyers) was a big enough deterrent to wide adoption?
I think the more likely culprit of the scarcity of the whisper round was marketability...if the military isn't shooting it or it doesn't offer significant "realistic" improvements to existing rounds...it's probably going be a relegated to a niche market. So I wonder what will happen with this round?
I'd really like to see some more on the SPL numbers for this thing with an aac 762-sdn-6 suppressor and 9" barrel compared to a 9mm w/ 147 grain subsonic loads and an appropriate suppressor. I find in hard to believe (but not implausible) that it's quieter than appropriately suppressed mp5 shooting subsonic rounds (as claimed in the article). Even if it comes close to 9mm suppressed SPL levels...it's damn impressive to have something with that much power be so quiet.