No guarantee that it is the correct caliber if it won't go in the barrel! They may have put the wrong caliber in the wrong package. Weirder things have happened! What ever you do, do not try to force it! Call the company and advise them of your problem.
The Constitution is not an instrument for the Government to restrain the people. It is an instrument for the people to restrain the Government!
“Americans have the right and advantage of being armed. Unlike the people of other countries, whose leaders are afraid to trust them with arms.”
James Madison. Author of the 2nd Amendment