The battle over Pennsylvania's ban on most Sunday hunting is heating up again, and this time the field of fire is in federal court.

Hunters United for Sunday Hunting, a Lancaster County-based sportsmen's group, has filed suit in U.S. Middle District Court in Harrisburg, seeking to have the ban voided on grounds that it is unconstitutional.

The defendant in the case is the state Game Commission, which enforces the hunting laws.

HUSH contends that the long-standing Sunday hunting ban violates federal and state protections of the right to bear arms and freedom of religion. Also, the group is claiming that the ban illegally creates two classes of hunters - the few who can hunt on Sundays by special provision and the vast majority who cannot.

And since the state's so-called Blue Laws that once barred most businesses from operating on Sundays were abolished years ago, there is no longer any rationale for the hunting ban to continue, HUSH contends in its suit.

Filing of the federal suit, which is assigned to Middle District Chief Judge Yvette Kane, comes two years after a widely-publicized, but abortive push in the state Legislature to lift the Sunday hunting prohibition.

The ban has powerful supporters, however, including the Pennsylvania Farm Bureau.

Travis Lau, a Game Commission spokesman, said Thursday that he did not know whether commission officials had received the HUSH suit. He said the commission's stance on the hunting ban issue is that it would be open to Sunday hunting if the Legislature were to authorize it.

In fact, the agency's board of commissioners adopted a resolution in October 2010 urging the Legislature to repeal the prohibition on Sunday hunting.

Lau said he was not aware of any currently pending proposed legislation that would allow hunting on Sundays.

Kathy Davis, executive director of HUSH, couldn't immediately be reached for comment.

The ban, which dates back decades, bars most hunting for large and small game on Sundays. However, feral swine, crows, foxes and coyotes may be hunted on Sundays, and farmers may kill deer and elk at any time on their own land if the animals are damaging their crops or property.

Pennsylvania is in the minority among the states in banning Sunday hunting. A legislative study released in 2011 concluded that Sunday hunting would generate more than $804 million in economic activity statewide.

HUSH argues in its lawsuit that the Sunday hunting ban unnecessarily causes hunters to "miss irreplaceable time during each seasonal hunting period."

"Given that most people work Monday through Friday and children under 18…are in school Monday through Friday, Sundays comprise 50 percent of the available time to hunt in Pennsylvania," the suit states.

The ban violates the constitutional right to bear arms, which includes protection of the right to hunt, the organization contends. Barring Sunday hunting has a religious restriction element that also violates federal freedom of religion protections, HUSH claims.

The group wants Kane to issue an order permanently barring the state from enforcing the Sunday hunting prohibition.