Major Republican donors, including some that have contributed to Gov. Greg Abbott’s campaigns, joined other conservative Texans in signing an open letter supporting congressional action to increase gun restrictions in response to the mass shooting in Uvalde that left 19 children and two teachers dead last week.

The letter, which is expected to run as a full-page ad in the Dallas Morning News on Sunday, endorses the creation of “red flag” laws, expanding background checks and raising the age to purchase a gun to 21. More than 250 self-declared gun enthusiasts signed it.

“Most law enforcement experts believe these measures would make a difference,” the letter reads. “And recent polls of fellow conservatives suggest that there is strong support for such gun-safety measures.”.....

Maclin said the group is focusing on federal legislation, which he believes is the best avenue to passing gun safety laws and ensuring they are applied uniformly across the country. He declined to comment on the state response to the shooting or gun legislation, except to say that he hopes any federal plan led by Cornyn and passed with conservative support would be embraced by state governments.

Among the signatories are deep-pocketed Abbott supporters, including billionaires Robert Rowling, whose holding company owns Omni Hotels, and Ray L. Hunt, executive chair of Hunt Consolidated Inc.