At the conclusion of the evidence defendants moved to dismiss the case on the grounds that the indictment against them was based solely on the perjured testimony of the State’s witness Joe Bill Deyton. The trial court’s denial of this motion constitutes defendants’ first assignment of error. Whether an indictment would ever be subject to dismissal on the foregoing grounds and, if so, under what circumstances, is a question we need not now explore since (1) there is no evidence that perjury was actually committed and (2) defendants’ motion to dismiss was untimely.

The sole witness before the grand jury was Joe Deyton, the arson victim. At the trial Deyton testified on direct examination that there were some “inaccuracies” in the statements he had made to the SBI agent who investigated the fire. He told the agent he saw defedants get into a 1966 Chevrolet which came by the motel after the fire began and that Dickie Phillips (Richard Godfrey Phillips) was the driver. Deyton explained that he had assumed Richard Phillips was the driver because Phillips had driven up to the store at Deyton’s motel many times in just such a car; and that, although he thought he had seen him, he couldn’t be sure. He also testified that he had assumed that the two defendants, both of whom he had seen running from the scene of the fire, were passengers in the car. On the morning of the trial Deyton told the district attorney about these assumptions and advised him that there would be a discrepancy between his trial testimony and his former statements.

Deyton admitted on cross-examination, over the State’s objection, 1 that his testimony before the grand jury and at the preliminary hearing contained the same inaccuracies. He explained that his former testimony was based on assumptions he had *605 made at the time of the fire, and. that he reported those assumptions as fact because “he was so upset and so tore up” by the shock .of his family’s narrow escape from death and the loss of his home and possessions.

These facts fall far short of establishing perjury. The com-monlaw definition of perjury-is “a false statement under oath, knowingly, willfully and designedly made in a proceeding in a court of competent jurisdiction ... as to some matter material to the issue or point in quéstion.” State v. Lucas, 244 N.C. 53, 54-55, 92 S.E. 2d 401, 402 (1956). There is nothing in Deyton’s testimony which suggests that the inaccuracies in his grand jury testimony were wilfull or designedly made. An unintentional misstatement of the facts is not perjurious.

Furthermore, we note that Richard Phillips’ testimony at trial fully verified the accuracy of Deyton’s assumptions. Phillips swore that he was in fact the driver of the car Deyton saw and that the two defendants did indeed get into the car after the fire began.

We also nóte that Deyton testified, both at trial and before the grand jury, that he saw two men running away from the fire carrying a gasoline can and recognized them as the defendants. This testimony, standing alone, provided ample cause for the grand jury to believe defendants were involved in the arson.

Finally, we call attention to the public policy of this State against allowing a defendant to' cross-examine the witnesses before the grand jury in order to show the nature and character of the evidence upon which the bill of indictment • was founded. State v. Blanton, 227 N.C. 517, 523-24, 42 S.E. 2d 663, 667 (1947). This policy is now codified in G.S. 15A-623(e). which states that “Grand jury proceedings are secret ¿nd, except as .expressly provided in this Article, members of .the grand jury and all persons present during its sessions shall keep its secrets.” See also G.S. 11-11. We agree with the trial judge that-the evidence elicited on cross-examination concerning Deyton’s grand jury appearance was not a proper subject for consideration on a motion to dismiss the indictment.

Under G.S. 15A-952(c) a motion to dismiss the indictment pursuant to G.S. 15A-955 “must be made at or before the time of ar *606 raignment if arraignment is held prior to the session of court for which the trial is calendared.” If arraignment is held during the session, the motion must be filed “on or before five o’clock p.m. on the Wednesday prior to the session when trial of the case begins.” A failure to make the motion in apt time constitutes a “waiver.” G.S. 15A-952(e). The trial judge, however, has the power to “grant relief from any waiver except failure to move to dismiss for improper venue.” Id.

Other than specifying, arraignment as the proper time for making the motion, these statutory rules substantially follow common-law practice. Under the common law of this State a motion to quash the indictment could be made as of right only up to the time the defendant entered his plea. Thereafter, the motion was addressed to the sound discretion of the trial judge. State v. Colson, 262 N.C. 506, 138 S.E. 2d 121 (1964). See also, State v. Ballenger, 247 N.C. 260, 100 S.E. 2d 845 (1957); State v. Suddreth, 223 N.C. 610, 27 S.E. 2d 623 (1943); State v. Burnett, 142 N.C. 577, 55 S.E. 72 (1906); State v. Eason, 70 N.C. 88, 90 (1874).

Defendants’ motion to dismiss came at the conclusion of the evidence. Under either common-law practice or G.S. 15A-952, the motion was untimely and was therefore addressed to the discretion of the trial judge. State v. Ballenger, supra; State v. Suddreth, supra; G.S. 15A-952(e). His exercise of that discretion in refusing to hear the motion is not reviewable on appeal. State v. Colson, supra; State v. Ballenger, supra.

In their second assignment of error defendants argue that the trial court erred in charging the jury that Richard Godfrey Phillips had testified under a grant of immunity. Defendants contend that the order dated April 24, 1978, granting immunity was ineffective because Phillips never formally asserted his privilege against self-incrimination as required by G.S. 15A-1051(b).

Because the privilege against self-incrimination is a personal one 2 , the short answer to defendants’ second assignment is simply that they have no standing to challenge either the propriety or the effectiveness of a grant of immunity to a witness testifying against them. United States v. Braasch, 505 F. 2d 139 (7th Cir. *607 1974); United States v. Lewis, 456 F. 2d 404 (3d Cir. 1972); Lopez v. Burke, 413 F. 2d 992 (7th Cir. 1969); Commonwealth v. Simpson, 370 Mass. 119, 345 N.E. 2d 899 (1976); State v. Reed, 127 Vt. 532, 253 A. 2d 227 (1969). Furthermore, even if the grant of immunity were ineffective and the judge’s charge therefore superfluous, we fail to see how defendants could be prejudiced by an instruction telling the jury that Richard Phillips had been granted immunity and cautioning the jury to “scan and scrutinize [his] testimony with care before accepting it.”

Upon oral argument defendants expressly abandoned their two final assignments of error: (1) that the trial judge erred in granting a change of venue (a move they themselves requested), and (2) that they were denied the effective assistance of counsel. Notwithstanding, we have examined both of these assignments and find no merit in either.

Our careful review of the record discloses a trial free from prejudicial error.

No error.