It seems like I've lost count of the number of times that I've noticed some native speakers of American English pronounce the grapheme "or" in words like "world" as [oʊr] or [ɔr] rather than [ɜr].
However, that [oʊr]/[ɔr] pronunciation doesn't seem to be supported by M-W's A Pronouncing Dictionary of American English by John S. Kenyon and Thomas A. Knott.
Please, compare the pronunciation of world backed by both the Free Dictionary and M-W with that of former U.S. president George W. Bush in his news conference after the capture of Saddam Hussein.
The Free Dictionary (Please notice how AHD's supported pronunciation of world (transcribed as [wɜrld], though) sounds close to that of President Bush, but is different from both M-W's and the one just before on The Free Dictionary)
George W. Bush's news conference at 19:04
How To Pronounce "Word" vs. "World" AmEng (sounds close to G.W.´s prononciation.)
How To Pronounce "World" And "Word" (sounds close to Merriam-Webster's)