To light for what?
To just shoot?
Heck no, I have even tried the LWT 90gr 9mm slugs just to see what kind of velocity I could get out of it.
But that's just for paper or small varmints.
If you asking if the 140 is too light for deer. IMHO, loaded to its full potential YES its much too light. 2500 + FPS is attainable from a rifle barrel. Remember this bullet is designed to perform between about 1000 - 1600fps. Your average 357mag from a pistol will be lucky to get it moving 1300fps. From the handi maxi, you will likely get explosive expansion and very shallow penetration. Loaded down to 357 mag pistol velocities, it would work nicely!
Its THE bullet I use to use in my 8" Colt 357 for deer!!
If you must stay lighter, go with Hornady 158 FP for the maxi and the HP version for the mag. You can likely load them exactly the same.
CW