The Weimar Republic gun laws were passed in response to the post WWI spectacle of pitched street battles between left wing and right wing militias supporting parties who wanted to rule post-war Germany. One sage individual in the Reichstag recognized that these lawless radicals (Freikorps, Nazis, Communists, etc) would not be as affected as ordinary lawabiding citizens, and stated it did the dignity of the law no good to pass unenforceable statutes.
When the Nazis came to power, they did modify the laws. Germans loyal to the Reich saw some reduction in restrictions, but they really did clamp down on everyone else, particularly Jews and anyone who was basically not a Nazi.
Would the prospect of armed resistence have deterred the Nazi regime? When bishop of Munster gave a sermon denouncing the program of exterminating the incurably ill or the feeble-minded ("useless eaters") the Nazis backed off.
ADDED:
I have been following this off and on since about Feb 2007. I had previously saved three articles on this.
The opening shot was part of Fordham Law Review 2004 Symposium: The Second Amendment and the Future of Gun Regulation: Historical, Legal, Policy, and Cultural Perspectives. The article by Harcourt presented an attack on Halbrook, Jews for the Preservation of Firearms Ownership, etc. on their view of Nazi gun control as tyranny. Halbrook then responed to Harcourt, and then Halbrook wrote a more general article on the subject.
Bernard E. Harcourt, "On Gun Registration, the NRA, Adolf Hitler, and Nazi Gun Laws: Exploding the Gun Culture Wars (A Call to Historians)", Fordham Law Review, Vol 73 Iss 2 Article 11, p.653ff. 2004.
Stephen P. Halbrook,"Nazism, the Second Amendment, and the NRA: A Reply to Professor Harcourt", Texas Review of Law & Politics, Texas Review of Law & Politics, Vol 11, No.1, p.113-131. 23 Dec 2006.
Stephen P. Halbrook, ""Arms in the Hands of Jews are a Danger to Public Safety": Nazism, Firearms Registration and the Night of Broken Glass", St. Thomas Law Review, Vol 21, p.101-134. 16 Feb 2009.
What boogled my mind was that Harcourt (anti-NRA) quoted William Pierce, author of the ''Turner Diaries'' and leader of the neo-Nazi National Alliance and National Vanguard, as a
reliable source on the assertion that "German firearms legislation under Hitler, far from banning private ownership, actually facilitated the keeping and bearing of arms by German citizens..." (Harcourt at page 668) which is true if you don't count German Jews, et al. as citizens of the Third Reich. Harcourt did not deny "The Nazis sought to disarm and kill the Jewish population" (Harcourt at page 671). Harcourt claimed that Stephen Halbrook, Jews for the Preservation of Firearms Ownership (JPFO) and National Rifle Association (NRA) promote a myth of Nazi repression of firearms owners. Yes, the Nazis repressed only
certain firearms owners, not
all firearms owners. In fact Harcourt's quote from Halbrook ("German firearms laws and hysteria created against Jewish firearms owners played a major role in laying the groundwork for ... the Holocaust") actually supports the point the Nazis used selective gun control to suppress opposition and impose tyranny, but Harcourt ties it to claims the Nazis used registration to ID gun owners and confiscate all guns.
The exchange of criticism can be credited with producing Halbrook's book.
Stephen P. Halbrook, "Gun Control in the Third Reich: Disarming the Jews and "Enemies of the State", Independent Institute (November 1, 2013). ISBN-13: 978-1598131611.
http://www.amazon.com/Gun-Control-Third-Reich-Disarming/dp/1598131613/