have you heard of the 17 incinerator......a 30grain bullet at 6000fps from, a 50BMG case

Incinerator sounds like a tongue in cheek description of the aerodynamic heating suffered by the bullet.

What's the complete name, Barrel Incinerator?

Another look at the 6.8 Raptor concept by SIG:

-May serve as PDW

-18-20" version also being developed 

YouTube

US Army Prototype NGSW 6.8mm Raptor - All You Need to Know

This is a very unusual full powered battle rifle with an impossibly short barrel. Find out how this US Army prototype M4 replacement is able to achieve a hig...

At 6:37, there is a NGSW Update:

-plan to select NGSW winner Jan 2022 (aka next month)

-T&P Reports from 'highly placed source' that Textron weapons and ammo 'Failed to reach requirements of the Army' 

So, the US Army "could" not only replace the M4 & M249 in the infantry role (the goal of the NGSW program - and keep the M4 for the PDW role), but also finally replace all & every M4 in service, even for non-infantry purpose... that's an interesting move.

EmericD said:

So, the US Army "could" not only replace the M4 & M249 in the infantry role (the goal of the NGSW program - and keep the M4 for the PDW role), but also finally replace all & every M4 in service, even for non-infantry purpose... that's an interesting move

It could be a possibility. 

The issue to me is one of suppressors. 

-The Raptor unsupressed is very short (~Krinkov) but will be tremendously, possibly dangerously, loud. 

-The Raptor with suppressor (unless its the Brevis) will end up with a length comparable to the M4, making its PDW benefits dubious, especially when the added weight vs M4 + 20rd mags are factored in

On such short barrel, suppressor is 100% essential.

You can use such micro type unit , just so that you don't need double ear protection.  

Silent Steel Micro Streamer from Finland adds only 50mm in lenght but you would be looking at well over 150+DB with 9' barrel.

On this forum a number of years ago, RRBud and I joked about using 300 Win Mag out of a short-barreled machine gun for room clearing.  There would be no need for flash-bang grenades to disorient the bad guys!    

Man I'd love mini cans like that to be available on the American market.

The closest things we have are stuff like the Witt machine big body tu tu.

I've been considering picking one up for my 16" gun.

nincomp said:

On this forum a number of years ago, RRBud and I joked about using 300 Win Mag out of a short-barreled machine gun for room clearing.  There would be no need for flash-bang grenades to disorient the bad guys

Funny you mention that, a week ago on AR15 Forum, a member was showing off their 8" .300 Win Mag Nemo Omen, which was the first thing I had thought of when the 6.8 Raptor was debuted:

And then a photo of it firing:

Description was very flashbang:

"It gives minor concussions I think, I had to lay down on the couch and regroup the same day shooting it, and it will eliminate all your knuckle hair. It has a very mild recoil, which I assume is because 80% of the powder burn is outside the barrel."