This merely follows Federal Law.
What I always find interesting is that some law that benefits the people, like permitless or shall issue concealed carry, always takes months to become effective, but any criminal law that can be used against a citizen is always effective immediately.

New Indiana law redefines ‘machine gun’ to include conversion switches

A new state law makes it illegal for Hoosiers to attach to their firearms a “switch,” or any similar device, that enables fully automatic shooting with a single pull of the trigger.

Republican Gov. Eric Holcomb approved the revised state definition of “machine gun” in House Enrolled Act 1365 on Thursday after the legislation was endorsed 71-23 by the Republican-controlled House and 45-4 in the Republican-controlled Senate.

Rep. Kendell Culp, R-Rensselaer, and Sen. Lonnie Randolph, D-East Chicago, are the only Northwest Indiana lawmakers to not support the proposal.

The statute took effect upon the governor signing it into law.

Advocates for the measure said the plastic switches, also known as Glock switches, are being purchased or 3-D printed throughout the state and increasingly used to convert regular guns into machine guns — with deadly consequences.

“It’s very difficult to control a firearm with one of these devices attached to it. So our constituents’ homes, businesses, cars and our constituents themselves are being caught in the crossfire,” said sponsor Rep. Mitch Gore, D-Indianapolis.

“These devices allow shooters to fire off dozens of rounds in just a matter of seconds. When police respond to these shootings, they are quite literally being outgunned.”

The mere possession of a switch already was illegal under federal law. The new Indiana law ensures that any person with a switch attached to their gun is subject to a variety of state penalty enhancements for the possession or use of a machine gun.

“As a career law enforcement officer and a representative of a district that has seen several instances of gun violence, I know this bill will save the lives of citizens and cops alike and make our streets safer for Hoosier families,” Gore said.

In a statement, Gore thanked his Statehouse colleagues, especially the strong Second Amendment supporters, for recognizing the importance of holding accountable people who illegally convert their standard firearms into machine guns.

“The significance of passing a piece of bipartisan gun legislation in Indiana is not lost on me,” he said. “I also want to thank Governor Holcomb for signing this bill and helping the General Assembly keep families safe while respecting Hoosiers and their constitutional rights.”

Additional supporters include the Indiana Fraternal Order of Police, Indiana Association of Chiefs of Police, and the Indiana Prosecuting Attorneys Council.