Defendant appeals his conviction for robbery in the second degree. His only assignment is that the trial court erred by not granting his motion for mistrial. The issue is whether the court impermissibly limited defendant’s cross-examination of co-defendant Newton. We affirm.
The incident which precipitated the charge occurred when defendant and co-defendant Newton encountered Ortiz, the robbery victim, as he walked along the railroad track leading from Odell, Oregon. The victim is Hispanic, he does not speak or understand English and he testified through an interpreter. He stated that he was walking along the railroad tracks toward Odell to do his laundry, which he was carrying in a small bag. He saw defendant and Newton approaching from Odell; they were both carrying rifles and stopped in front of him. They both pointed their guns at his stomach and said “give me your money,” and he took his wallet from his pocket and threw it on the ground. He stated that one of the men picked it up and, when he started to leave, defendant signalled him to leave the laundry bag. He dropped it, went a short distance, turned and saw both men leave with his wallet and the laundry bag. He identified defendant as one of the men and testified that defendant pointed a gun at him. Ortiz later found the laundry bag near the railroad track but did not find the wallet. He identified defendant from a photo lineup shown to him by a police officer, and he positively identified defendant in court.
Defendant testified in his own behalf, and his testimony fairly disclosed this narrative. He and Newton were working on a farm near Odell tearing down a barn. On the day the robbery occurred, the two men did some target practice with two rifles in the morning. Defendant shot all of the ammunition that he had with him. Later in the day, after they had quit work, they took both rifles and walked into Odell. As they were returning, walking on the railroad track, they saw Ortiz. Defendant walked past, and Newton stopped in front of Ortiz. Defendant, who was about three or four feet away, heard Ortiz say something in Spanish, which he did not understand. Newton said something to Ortiz, which defendant did not hear clearly, because he is deaf in one ear. He testified that his rifle was hung on his shoulder by the shoulder strap with *29the muzzle pointing straight up and that Newton was carrying his rifle at his side with the muzzle pointing forward and down. Defendant said that his gun was empty and that he did not know if Newton’s gun was loaded.
He testified that it appeared that Newton and Ortiz were about to fight. Ortiz then threw defendant his wallet and defendant threw it back. Ortiz put the wallet in his pocket and, after Ortiz and Newton exchanged more words, threw the wallet down at defendant’s feet, dropped the laundry bag and ran. Defendant stated that he picked up the wallet, Newton picked up the laundry bag and they ran the other way, because they were afraid that Ortiz would return with “more Mexicans.” He stated that he went through the wallet and that Newton went through the laundry bag and took a box of soap. He testified that they spent the money that was in the wallet.
Newton had been convicted of robbery in the first degree in a separate trial arising out of the same incident, but had not been sentenced at the time of defendant’s trial. The state called Newton as a witness in its case in chief and, when he was questioned outside the presence of the jury, he invoked his privilege against self-incrimination in response to all questions relating to the robbery and did not testify. After defendant had rested and the state had presented one rebuttal witness, the court recessed the trial for that day. The following morning the state informed the court it wished to call Newton as a rebuttal witness for the limited purpose of asking him three questions regarding whether there were bullets in defendant’s gun as the men walked along the railroad away from Odell. Defendant’s counsel agreed that the prosecutor was surprised by Newton’s decision to testify and that there was no prosecutorial misconduct or collusion involved in Newton’s decision. Newton’s counsel appeared with him and, during the subsequent offer of proof, said that Newton had decided to give limited testimony contrary to his advice and that it was his opinion that Newton could incriminate himself by his responses.
Newton testified in an offer of proof that he and defendant walked into Odell on the railroad tracks and that they both had rifles which they shot on their way into town and that the rifles had bullets in them on the way back from Odell. During the offer of proof, defendant’s counsel cross-*30examined extensively regarding Newton’s testimony about there being bullets in the guns. She then asked if Ortiz had tried to take a swing at him. Newton refused to answer saying: “I respectfully take the Fifth.” There followed an extended colloquy between court and counsel, which also involved Newton’s attorney. The discussion concerned whether Newton had a right not to incriminate himself at that juncture and whether, if the court ordered him to testify, that would be tantamount to a grant of immunity that could effect any possible retrial of Newton. The court ordered Newton to answer the question.1 Defendant’s counsel then asked how far she could go on her cross-examination, and the court invited an exploratory question. She asked:
“What I would like from you, Mr. Newton, is a statement of what happened on the transaction when you met Mr. Ortiz?”
In response to the state’s objection, the court ruled:
“That is too far. I am not concerned about his Fifth Amendment privilege, I am concerned about keeping it within the scope of rebuttal or reasonably within the scope of rebuttal or the scope of the direct examination.”
Before Newton’s testimony in front of the jury, the court, at defendant’s request, told the jury that Newton was a codefendant and was unavailable to either side during their respective cases in chief. The court then instructed:
“Mr. Newton is available to address only limited issues at this time and you should draw no conclusions from the limited nature of those issues or from his unavailability to either side at an earlier stage of the trial.”
On direct examination, Newton testified about the agreement regarding sentencing and to what he had testified during the offer of proof, i.e., that there were bullets in the rifles on the way back from Odell. He additionally testified that defendant’s rifle had a thirty-shot clip.
Defendant’s counsel cross-examined him regarding *31his knowledge of guns and his motive for testifying, but did not ask any questions about the confrontation with Ortiz. Defendant moved for mistrial and explained:
“The reason for that motion is I feel that the defendant is being substantially prejudiced by being unable to confront Mr. Newton and bring in testimony that would be helpful to his case. I am not alleging at this point that the prosecutor kept this witness away from me, but it is gratuitous for him that this witness has not been available for any of my case so I can bring out anything that can substantiate my client’s case and the only things that are going to be able to come in are things that are going to substantiate the prosecutor’s case. I understand Mr. Newton’s Fifth Amendment concerns and I am hemmed in so I cannot represent my client; he does not have a right to confront this witness.”
The motion was denied. Defendant testified on surrebuttal and reiterated that he had shot all of the ammunition he had with him earlier in the day. He also testified that he had only a fifteen shot clip for the gun and identified the gun in evidence as his with the fifteen round clip.
After deliberating for a period of time, the jury sent the following question to the court:
“The jury needs clarification on whether or not the gun or guns were loaded, and the point which determines the difference between Robbery One and Robbery Two.”
The court reinstructed on those two crimes and defined the term “deadly weapon.” The presiding juror said, orally:
“There was a misunderstanding in the group. * * * It’s simply whether a weapon, a gun specifically, is a deadly weapon when it’s unloaded.”
The court responded that the jury would just have to be satisfied with the instructions given.
Although defendant had been charged with robbery in the first degree, ORS 164.415, the jury found him guilty of robbery in the second degree, ORS 164.405, a lesser included offense. The distinction between those two charges is that, in first degree robbery, the state must prove that defendant was armed with a deadly weapon, while in second degree robbery it must prove that defendant represented by word or conduct that he was armed with what purported to be a deadly weapon. In the contemplation of the prosecutor, defense counsel and *32the court, that distinction boiled down to the question of whether or not defendant’s gun was loaded at the time when he and Newton confronted the victim.2 It is clear from the record that a principal issue at trial was not whether defendant was involved but whether he was guilty of first or second degree robbery.
On appeal, defendant makes essentially two arguments in support of his motion for mistrial: first, that Newton should not have been allowed to testify at all, because he had earlier asserted his right not to testify and incriminate himself; and second, that, by limiting defendant’s cross-examination of Newton, the court violated his rights to confrontation and a fair trial.3
Defendant’s first contention is unpersuasive. A witness who invokes the privilege against self-incrimination exercises a constitutional right that is personal. Neither the defendant nor the state may control the witness’ exercise of the right. State v. Abbott, 275 Or 611, 552 P2d 238 (1976); State v. Johnson, 243 Or 532, 413 P2d 383 (1966). After invoking the privilege, a witness may withdraw the claim as to all or any part of his testimony. Newton was free to waive the right in whole or in part and to testify in rebuttal for the prosecution.
Defendant’s second contention is that he was denied effective confrontation of the witness, because cross-examination was limited. OEC 611(2) provides:
“Cross-examination should be limited to the subject matter of the direct examination and matters affecting the credibility of the witness. The Court may, in the exercise of discretion, permit inquiry into additional matters as if on direct examination.”
That rule of evidence reposes discretion in the trial court, both as to whether the question on cross-examination relates to the subject matter of the direct examination and whether the cross-examiner should be allowed a broader range of inquiry. *33The court exercised its discretion in both respects in this case, and our inquiry is whether it abused its discretion.
The subject matter of the direct examination was very limited: it related only to whether defendant’s gun was loaded as the two men walked back from Odell. That limited testimony was offered to rebut directly defendant’s statement that his gun was not lqaded. Defendant argues that Newton’s statement that the guns..were loaded on the way back from Odell opened up cross-examination as to what occurred as the two men walked along the tracks, more particularly, what had occurred when they confronted Ortiz. The question asked by defendant’s counsel on cross-examination, which provoked the court’s ruling, had some relationship to what Newton had testified to on direct examination, but that does not make the cross-examination appropriate as a matter of law or make the ruling an abuse of discretion. The court was well aware that a central issue in the case was whether defendant’s gun was loaded and thus whether he would be guilty of first or second degree robbery.
In addition to the relationship between the question on cross-examination and the subject matter of the direct testimony, the court may take other factors into consideration in ruling under OEC 611(2).
Another factor is whether the inquiry will unduly prolong the trial or interject issues that are not germane to the trial at the juncture of the proceeding. It is clear from the record that defendant was interested in bringing out additional testimony from Newton about the actual robbery that might have been favorable. The question asked and not allowed raised questions of Newton’s right to assert a privilege not to incriminate himself. His attorney was present during the offer of proof when Newton, on the attorney’s advice, asserted a Fifth Amendment privilege not to answer questions relating to the actual confrontation. The court ordered him to answer one question but was aware that his attorney would advise him to assert the privilege in response to questions directed at his participation in the robbery. The court was faced with thorny questions as to whether Newton had waived his Fifth Amendment rights and whether ordering him to testify would immunize him from retrial, if his conviction were *34set aside or were reversed on appeal. The court properly considered those problems in determining if the inquiry on cross-examination should be limited.
The court also considered another factor: whether defendant had a reasonable opportunity to test the witness’ motive for testifying, his memory, his perception and his credibility, which is the principal purpose of cross-examination. Defendant’s counsel examined Newton thoroughly regarding those factors as they related to his direct testimony. Proof of counsel’s effectiveness is that the jury, by its questions and verdict, obviously rejected Newton’s testimony. Defendant was not deprived of rights of confrontation in terms of full cross-examination. See Davis v. Alaska, 415 US 308, 94 S Ct 1105, 39 L Ed 2d 347 (1974). The restriction imposed by the court’s ruling only prevented defendant from making Newton his own witness, which the court could allow or deny in its discretion. OEC 611(2). Defendant’s confrontation rights were not eclipsed by the court’s ruling.
Even if the limitation on cross-examination was error in the abstract, as the dissent suggests, it does not follow, as a matter of course, that denial of a mistrial was error or reversible error. A trial court has broad discretion in ruling on a motion for mistrial, the granting of which results in aborting the trial and a possible retrial. In State v. McFarland, 30 Or App 93, 566 P2d 539, rev den 280 Or 397 (1977), we said:
“The trial court’s discretion, however, is not without bounds, and a motion for mistrial should be granted when it is apparent that some aspect of the conduct of the trial has interfered with a defendant’s ability to obtain a fair adjudication of the facts.” 30 Or App at 97.
In essence, the inquiry is whether a mistrial is necessary for defendant ultimately to get a fair trial. The same type of inquiry is appropriate in deciding if there was reversible error in the trial and whether defendant must have a new trial in order to have a fair adjudication. In the light of the evidence presented, and the principal issue, i.e., whether defendant’s gun was loaded, it is highly unlikely that cross-examination of Newton as defendant proposed would have altered the outcome. Defendant received a fair adjudication of the issues of his guilt, and the trial court did not err in denying his motion for mistrial.
*35Affirmed.
Defendant’s counsel rephrased the question after the court’s ruling:
“Q. At a prior hearing, didn’t you testify that Mr. Ortiz, in your encounter with Mr. Ortiz, that he first tried to take a swing at you?
“A. Yes, that is correct.”
The court instructed the jury:
“The term ‘deadly weapon’ means any instrument, article or substance specifically designed for and presently capable of causing death or serious physical injury.”
Defendant did not specify which constitution he was invoking — state or federal.