9mm based Grendel?

[mopar_4life]

[tdbru]

do a web search on the 9x39. the Soviets did this for subsonic applications decades ago. you could neck up a 7.62x39 case and fireform in custom chamber. you might call Manson Reamers or JGS reamers. they may have a reamer on the shelf already. i'm sure you're not the first one to think of this, not to be demeaning in anyway. lets just say great minds think alike :-) of course you'd need a barrel setup for it. Not sure if you're thinking bolt gun or AR platform. anything is possible of course.
-tdbru

[mblackmon4]

Wolf used to import 9x39, think Russian blackout cartridge. Unfortunately importation days are long gone but you can occasionally find a dusty box in along forgotten about corner in small LGS.

[LR1955]

MOPAR:

Know what? I think this has some real potential for the applications you state. You ought to pursue it more.

LR-55

[41bear]

If you don't want to go the custom route you might give the 350 Legend a look, Faxon makes both a pistol barrel and two rifle barrels. As for using the 200 gr. 358 bullet I wedge them down.
Hope this helps.

[tdbru]

if one is wanting to try some 9mm/358 very heavy bullets with the 350 Legend, you'll likely have to custom order a much faster twist barrel. If I recall, SAAMI is only 1-16". if you want to try 280-310 or more, at subsonic speeds, for instance, I would estimate a 10" twist might be required. The 350 Legend does indeed look, "interesting", but I'd pursue a much faster twist if my intent with the 350 Legend was Subsonic usages. Just mentioning is all.
-tdbru

[41bear]

if one is wanting to try some 9mm/358 very heavy bullets with the 350 Legend, you'll likely have to custom order a much faster twist barrel. If I recall, SAAMI is only 1-16". if you want to try 280-310 or more, at subsonic speeds, for instance, I would estimate a 10" twist might be required. The 350 Legend does indeed look, "interesting", but I'd pursue a much faster twist if my intent with the 350 Legend was Subsonic usages. Just mentioning is all.
-tdbru

Though you may be correct both Winchester and Hornady have heavy (250 gr.?) sub loads on the market just for the 350 Legend.