In this appeal from a jury conviction of housebreaking, housebreaking while armed with a weapon, assault with a dangerous weapon, and carrying a dangerous weapon, only one reason is advanced for reversal. It is that the trial court abused its discretion — to the point of plain error within the meaning of Rule 52(b), FED.R.CRIM.P. — by permitting the prosecution to bring out on cross-examination of appellant a prior conviction for the last of these offenses.1

It may well be true, as appellant argues, that this prior conviction played some part in shaping the jury's conclusions. The question of whether the gun in the case belonged to the complaining witness or to appellant was contested at length in the testimony, and presumably occupied a central place in the jury's view of the whole case. But that this was likely to happen must have been evident in advance, and yet the defense made no effort, before appellant took the witness stand, to raise with the trial court the question of whether this prior conviction should be kept out in order to assure the availability to the jury of the accused's version of the events in dispute. See Luck v. United States, 121 U.S.App. D.C. 151, 348 F.2d 763 (1965). And even when the prosecutor, with commendable sensitivity to the significance of the matter, interrupted his cross-examination for the purpose of approaching the bench to inform the court and defense counsel that he was about to ask about the prior convictions, no objection of any kind was made. The usual instruction was given to the jury to confine its consideration of the prior convictions to the issue of credibility; and the closing argument of the Government to the jury was devoid of reference to them. Under these circumstances, we are not disposed to characterize as plain error an alleged abuse of a discretion which was never invoked.

Affirmed.