I could never find chrono results for this load from a rifle so I did it myself.

I only had 1 box of 20 round and the first one I messed up and it didn't get read so here is the average velocity of 19 rounds of Underwood 200gr hardcast .40 S&W.

1,210 FPS

This is a 210 FPS increase from the carbine as compare to the box factory label spec of 1,000.

Note that this is still less than 10mm from a pistol.

Pistol caliber carbines are cool but a .40, even from a rifle, still ain't a 10mm.

PS other results were interesting as well (for example an average increase of 275 FPS from standard pressure .38 Spcl130gr FMJ between a 3" S&W model 60 and an 18.5" Marlin and over 600 FPS increase with 158gr SJHP .357 mag).