A Virginia man charged with stockpiling the largest number of finished explosives in FBI history and accused of making threatening comments about politicians has pleaded guilty in federal court to possession of an unregistered short barrel rifle and possession of unregistered destructive devices.Authorities seized around 150 pipe bombs and other explosive devices from Brad Spaffords home near Norfolk last fall, according to court documents.Spafford was also accused by prosecutors of using former President Joe Biden's photo for target practice, saying "he believed political assassinations should be brought back"and telling someone shortly after President Donald Trump's assassination attempt, "Bro, I hope the shooter doesnt miss Kamala," according to an informant.MAN ARRESTED NEAR 'NO KINGS' PROTEST ALLEGEDLY HAD STASH OF PIPE BOMBS AT HOMEThe investigation into Spafford began in 2023, when the informant, who is in law enforcement, told authorities Spafford was stockpiling ammunition and weapons.Authorities found a highly unstable explosive material in a freezer next to frozen foods and more explosive material inside a backpack that said "#NoLivesMatter" while searching his home in December.FBI DEPUTY DIRECTOR DAN BONGINO CLAIMS BUREAU CLOSING IN ON SUSPECTS WHO PLANTED JAN. 6 DC PIPE BOMBSSpafford has remained in custody since his arrest in December, when a judge ruled he had "shown the capacity for extreme danger."He originally pleaded not guilty in January, and his defense argued he should be released because he had a steady job and no criminal record.Spafford, who is married with two young daughters, lost three fingers in a homemade explosives accident in 2021, the judge noted.CLICK HERE TO GET THE FOX NEWS APPSpafford could face 10 years in prison on each charge and is scheduled to be sentenced in December.The Associated Press contributed to this report.