That is pretty shithouse if they are undersized.
I would just make sure it isn't a burr on the edge (countersinking tool should clean it up in 1 second) and if it's still tight, then yeah, drill it out to 1/2" as the others have said.
Pressing them in shouldn't have made any difference to the I.D. of that tube. It would have been too tight even before you installed them I imagin, if they're tight now.
Make sure you coat those bolts in a thin layer of copper anti-seize before insertion, particularly as you'll be losing any zinc coating that's on the crush-tubes by drilling them out.