In the case of Meyers v. United States (84 U.S.App.DC. 101, 171 F.2d 800 (1948)), Meyers was being prosecuted for subordination of perjury in front of a Senate subcommittee.  A key issue was the testimony of a guy named Lamarre.  At the perjury trial, even though the stenographic record of Lamarre's testimony was available, the Trial Judge allowed the prosecution to have a witness recount the substance of Lamarre's testimony. Meyers objected, but the Appellate Court affirmed, saying that the recounting was not a violation of the best evidence rule because it wasn't the contents of the transcript that were at issue, it was Lamarre's oral testimony.  The stenographic record would be good evidence of what was said, but it wasn't the only possible admissible evidence of his testimony. Statements that are alleged to be perjurious may be proved by any person who heard them, as well by the court record. In a dissent it was argued that the best evidence rule should be read more generally, and to require that a party having available evidence which is relatively certain may not submit evidence that is far less certain. Basically, the dissent felt that if there was better evidence, then the party should be required to present it, regardless of the technical reason for offering the evidence. If Meyers felt that the testimony was inaccurate, he could have introduced the stenographic record himself.  Then the jury would have to determine how much weight to give the testimony vs. the transcript.