Fact check - Republicans are doing the same thing with this nomination. Standard mode of operation for both parties.
I am no fan of liberal Supreme Court nominees, but this has to be said. Yesterday, the issue of gun rights did come up and her response was documented:
On the Second Amendment: "Do you believe the individual right to keep and bear arms is a fundamental right," Iowa Republican Senator Chuck Grassley asked the nominee. "Senator," she responded, "the Supreme Court has established that the individual right to keep and bear arms is a fundamental right." Her answer echoes a written response she gave during her confirmation hearing last year for the D.C. Court of Appeals
Justice Breyer has never made such a statement and is always a dissenting voice on gun rights issues.
Justice Breyer has long defended the constitutionality of gun safety measures from the bench. At oral argument in New York State Rifle and Pistol Association, Inc. v. Bruen, a case which the Supreme Court heard this past November and is yet to rule on, he noted that areas with more lax gun carry laws see higher rates of gun violence. Furthermore, he authored key dissenting opinions in District of Columbia v. Heller and McDonald v. City of Chicago, setting forth his view of why the Second Amendment was not incompatible with the gun regulations at issue in those cases.
Only time will tell, but appears to be net neutral effect on the Court.