Have gun rights ever increased without a revolution?

In Visigothic Hispania, only the Visigothic ruling class could bear arms. When the Moors invaded in 711 AD, only the Visigothic ruling class could offer resistance. After the Moorish conquest, restrictions on arms were relaxed and the tax burden was lightened. Once the tax burden was increased, the ongoing Christian Reconquista gained momentum.

_{Work in progress. Recalling what was stated in a documentary I watched years ago. Please consider the above highly dubious until I have found corroboration by reputed historians. If corroboration is not found, this answer will be deleted.}

Bliss v. the Commonwealth (of Kentucky) advanced gun rights in the US:

Bliss stated, "But it should not be forgotten, that it is not only a part of the right that is secured by the constitution; it is the right entire and complete, as it existed at the adoption of the constitution; and if any portion of that right be impaired, immaterial how small the part may be, and immaterial the order of time at which it be done, it is equally forbidden by the constitution."[15] The "constitution" mentioned in this quote refers to Kentucky's Constitution

The importance of Bliss is also seen from the defense subsequently given against a murder charge in Kentucky against Mattews Ward, who in 1852 pulled out a concealed pistol and fatally wounded his brother's teacher over an accusation regarding eating chestnuts in class. Ward's defense team consisted of eighteen lawyers, including U.S. Senator John Crittenden, former Governor of Kentucky, and former United States Attorney General. The defense successfully defended Ward in 1854 through an assertion that "a man has a right to carry arms; I am aware of nothing in the laws of God or man, prohibiting it. The Constitution of Kentucky and our Bill of Rights guarantee it. The Legislature once passed an act forbidding it, but it was decided unconstitutional, and overruled by our highest tribunal, the Court of Appeals." As noted by Cornell, "Ward's lawyers took advantage of the doctrine advanced in Bliss and wrapped their client's action under the banner of a constitutional right to bear arms. Ward was acquitted.

This is the basis of much of the "can't regulate guns" thinking in the US today.

Most gun legislation may add regulation, but not all of it does. The Law Enforcement Officers Safety Act of 2004 created new gun rights for two classes of individuals, the "qualified law enforcement officer" and the "qualified retired or separated law enforcement officer". The Wikipedia article on the act lists several cases in which individuals were allowed to carry firearms, after establishing that they belonged to qualifying classes, in situations where same would otherwise be prohibited.

As a law, not a ruling, I believe that this change passes the strict test proposed by SJuan76 above.

Germany in the 20ties and 30ties. Even if you count conservatives delivering political power to the Nazis as a revolution. I'll paraphrase German Wikipedia:

• Immediately after WWI, private gun ownership was outlawed, however this was impossible to enforce because guns were not registered. Especially post Freikorps right wing militias (Schwarze Reichswehr) were well armed

• In 1928, Germany got its first unified gun law. Private gun ownership was allowed. However, prospective buyers had to prove their "reliability" and an actual need for the weapon. Weapon owners needed a Waffenbesitzkarte and a Waffenschein (a license to be carried on the person)

• After 1933, the Nazis used the existing laws to harass Jews and political enemies: the police would withdraw the permit and use this as a pretext to search someones premises for weapons. This was targetted widely at Jews (in '33, Berlin's police chief withdrew all weapons permits from Jews) but also at other political enemies.

• Later, the Nazis would control who gets a gun: gun laws were relaxed for party members (a license was no longer necessary to carry a handgun, starting at certain ranks within NSDAP, SA, SS or Hitler Youth among others), while "Gypsies" and other were banned from gun ownership. Jews were excluded from gun or ammunition manufacture and sale. at the same time, the restrictions on longarm ownership were relaxed, permits were only required for handguns. A specific goal of this law was Wehrhaftmachung des Deutschen Volkes, to ready Germans for war.

• Later in 1938, after the November pogroms, a bylaw specifically forbade Jews guns or any other form of weapon ownership

So you certainly can say that in the 20ties, Germany increased gun rights - from none at all to legal gun ownership, based on permits.

Starting with the Nazi regime, the picture gets more complex. For a majority, the change in '38 meant easy access to long guns. For some organized Nazis it eased the carrying of a handgun. But at the same for many the regime deemd enemies, legal gun ownership had become impossible.

I don't know if the Nazi or Hitler ever systematically laid down their thoughts on private gun ownership, if they even were that coherent on that issue. They certainly didn't envision a disarmed population.

Surely. Just in 2008-2010, the judgments in Heller and McDonald and the settlement in Guy Montag Doe all expanded gun rights in the United States by constraining local authorities' ability to regulate firearms. No revolution needed!