[Nincomp]

The 400L uses a 0.422" diameter bolt like the 6.8 SPC, but case is a little larger diameter ( 0.44" vs 0.4207"). It also only runs at 45,000 psi and the case length is 1.65". It IS a member of the 30-30/ .30Rem/69 SPC family, but it is the short chubby uncle that is just a little off.

 

[Nincomp]

Good idea, Greentick. I get confused when the same topic is on several threads. Then again, I am old and easily cofused.😮‍💨

 

[Nincomp]

I'm guessing that is why they have the threshold lower. Not sure why that they would go rebated rim vs the x39 case head. The only thing that I can think of is that the x39 case head is really not ideal for the AR platform. But, at 45k psi, I would think that it might be alright. Since the Grendel's max psi is around 52k psi.

This cartridge is puzzling. It was shown in bolt guns for the intro video. My guess about the case is to play up its relation to the well known 30-30 and to be absolutely certain that there would be no bolt problems. It depends on how much say the Marketing Department had. The lower pressure probably has something to do with available bullets, too, but it is also possible that it is engineered around some particular rifles with marginal bolt strength. They might even be thinking of some lever actions like the Marlin 336 that could use the rimless 35 Rem.

 

[Nincomp]

Rather, this round is based on the 6.5 (and 7.35) Carcano/220Russian/7.62x39/220ppc/5.45x39/9x39/Grendell/ARC case family. Head and body diameters bear this out. The 400L has the rim rebated to .422" from the origional .447" of those cases.

This combination gives a few advantages. The added body taper compared to the 400AR and similar earlier 30Rem/spc/etc based .40 wildcats greatly aids feeding. A 40 cal rifle round based on the 30rem/spc/etc case is basically straight.

The base of the case is only 1 thousandth of an inch smaller than the Grendel/ARC case, so that is possible. The odd thing is the 45,000 psi max pressure vs the 52,0000 for the Grendel/ARC. It makes me wonder if there were bullet issues or if the pressure was held down for a particular rifle design. Possibly a lever action?

 

[Nincomp]

I see that ammo is available from numerous sources, so I haven't given up hope yet.

edited to add: I checked Savage, Ruger and Winchester but didn't see anything listed. I am beginning to wonder if something bad was discovered during initial testing.

 

[Nincomp]

It really is a legend.

"Legend" is OK. Let's just hope that it just doesn't turn out to be a MYTH!