What, you mean one of these?
As stated, the gun is boringly reliable, suprisingly accurate and has a very decent trigger pull weight.
Don't try shooting 9mm Parabellum, 9 Steyer, or .380acp in one of these Model 400s, you are asking for trouble.
Shoot only 9mm Parabellum, Luger, whateve
r you wish to call it, ammunition in a Model 600, anything else can and probably will ruin the gun.
Most work best with plain old full metal jacket loadings, you just don't need hollowpoints in these old guns.
If your Model 400 is marked '9mm/38 it has a chamber that will accomodate .38acp ammunition along with the original 9mm Largo ammunition.
If the chamber is marked '9mm L' or '9mm' it is only chambered for the Largo/Bergmann-Bayard cartridges and it will probably malfunction if you try the .38 acp/super stuff in it.
Modern Commercial .38 Super should work in a 9mm/.38 marked
gun too but have a gunsmith look it over before you decide to shoot any and stick with standard .38 super full metal jacket 'promotional loads', i.e. Winchester white box, Remington yellow box, etc.
This stuff is actually loaded pretty mild for Super, it is really is closer to .38acp loading and i think the ammo companies do this intentionally in case somebody stuffs some into an old Colt .38 automatic.
I have some Santa Barbara 9mm Largo and it is a ballistic twin of the original .38 super load, 1350 fps, 450 fpe.
If this is intended for the Astra 400, the Llama and the Star, I see no reason why .38 Super ammunition couldn't still be fired in the gun, if it is in good shape
.38 Super Silvertips worked fine in my gun too but I really see no reason to use them, the pistol is a fun gun, not a defense piece.