The real story behind my question
OK, folks, thanks so far and here a bit more info or clarification:
The purpose is defense against a specific BG who tried to kill us before with a knife, was on speed, failed, and now is in a mental institution about to be released soon. Our legal system makes sure that we won't be told when he's loose again. Sad but true.
I do carry a handgun 24/7 anyway and I am pretty good with my pistols and my knife and my hands (years of training with and against each of these).
But: A family member of the specific BG and the BG himself were at our doorstep before they entered and when I have the time for it, I want a rifle or shotgun to grab before he makes it through our door or windows. If there's no time, my Glocks will do the job. But as I see a handgun only as an emergency tool on my way to a long gun I ask myself the posted question.
For my home-defense I have a Steyr AUG Semi Auto Bullpup .223 with 30 and 42rds Magazines. That's as good as a defense rifle gets IMHO.
The BGs last attack happend in our office (he also tried to hit us at home after he hit the office). So I also want a long gun for the office. I don't want to buy another AUG. So my favorites are a lever-action Marlin or a 12ga Coach gun.
I am well into ballistics and know that the weight of the .44 Mag Bullet causes it to overpenetrate and be rather ineffective in Humans. Thats why I hesitate. My personal favorit defense rifle cartridge is the .223 with Federal Law Enforcement LE223T3 bullets. I can buy these legally here. A .223 64gr soft point is similar but not as excellent through and after glass.
So, given all these facts, I hope and/or think that the .30-30 with a light (125gr etc) bullet would penetrate less than the .44 from a Marlin and do at least the same damage to a human. But since I am not a hunter, I have no personal terminal ballistic experience yet.
PS: The pic posted above shows a Barnes .308 Bullet in gel. I couldn't find a gel-pic of a Barnes-bullet in .44, sorry.
PPS: And thanks for that link:
http://www.chuckhawks.com/handgun_rifle_cartridges.htm it was very informative indeed!