OPINION OF THE COURT
TALIAFERRO, Judge:Appellant was convicted, in a trial by special court-martial consisting of a military judge and four officer members, of six specifications alleging violation of general regulations by purchasing controlled items in excess of the regulatory monthly limit. His sentence to a bad-conduct discharge, and reduction to pay grade E-l was approved by the convening authority. Assigned errors are discussed herein seriatim.
I
A defense motion to suppress Prosecution Exhibits 2-7 (165 transaction cards) on grounds that the cards (records of controlled purchases) were made principally with a view toward prosecution, was denied by the military judge. Appellant now further contends the records were not admissible either as official records or as business entries. The military judge admitted the *640records as business entries, and we agree. The records were kept in the ordinary course of business — that being the business of operating a military exchange under the “controlled purchase” system. (R. 24). The witness, Commander Caruso, was intimately familiar with the conduct of the [exchange] operation . . .United States v. Wilson, 1 M.J. 325 (C.M.A.1976). We are convinced that these records, made at the time of each purchase, whether or not in any given case overpurchase might have been suspected, were not made “principally for the purpose of prosecution.” See United States v. Evans, 21 U.S.C.M.A. 579, 45 C.M.R. 353 (1972).
II
Appellant contends Prosecution Exhibit I, a compilation of the pertinent data from throughout the many entries on the voluminous transaction cards which comprise Prosecution Exhibits 2-7, was erroneously admitted, principally because the witness, Commander Caruso, did not “. [examine] and [summarize] the whole collection . . . ” personally or as a member of a group of qualified persons, as provided in paragraph 143a(2)(b), Manual for Courts-Martial, United States, 1969 (Revised edition). Commander Caruso testified that he had reviewed the summary after it had been prepared “. . . courtesy of the Law Center . . . ” but also testified that he had prepared the cards, and that he . . went by each card to make sure that amount was on that (the summary) at the time. . . . ” We hold this action constitutes compliance with the provisions of paragraph 143a(2)(b) supra. The military judge admitted the summary as “an aid to the court” with precautionary instructions to the effect that only the source documents were to be considered evidence. Compare United States v. Smyth, 556 F.2d 1179, 1183 (5th Cir. 1977). Admission of the summary into evidence was proper.
III
By his third assignment of error, appellant presents an anomaly. While he alleges error in that the convening authority did not personally select the military judge, he contends, at the same time, that the convening authority “will not detail Captain Kaplan to any ration control cases,” (R. 5) and that he relieved Captain Kaplan, detailing Colonel Hammack instead (R. 6) “for the trial of [the instant case] only.”1 Aside from that inconsistency, we find, as we did in Saunders2 that “The Government affirmatively established on the record the court’s jurisdiction when it announced without challenge by the defense the convening of the court and the referral to trial of charges by the appropriate authority.” We find no affirmative evidence in the record to overcome the presumption of regularity. United States v. Saunders, supra; United States v. Masusock, 1 U.S.C.M.A. 32, 1 C.M.R. 32 (1951).
IV
Contending that the court lacked jurisdiction for failure of the convening authority to sign Court-Martial Convening Order Number 19 before completion of the trial proceedings, appellant cites United States v. Ware, 5 M.J. 24 (C.M.A.1978). The facts in the instant case are clearly distinguishable from Ware, where the error of failure to issue a written order confirming an oral announcement of a change in the court was sought to be cured by an affidavit subsequent to the trial. Here, the convening order is part of the record, duly authenticated with the command line, showing it was promulgated on 22 June 1978, which was during the trial proceedings. In the absence of a showing to the contrary, we presume the order was effective on the date it bears.
V
Specifications n 1, 3 and 5 of the Charge allege that appellant violated the *641regulation by purchasing a specified number of “bottles” of liquor, in excess of the number authorized by the regulation. The regulation did not use the term “bottles,” but limited an individual to a quantity of four “Qts/fifth” per month. Appellant asserts that this portion of each specification in question fails to state an offense. We disagree. No essential element of the offense is omitted, nor do the specifications fail to fairly apprise appellant as to what he must meet at trial. He is adequately protected from further prosecution for the same acts. See United States v. Sell, 3 U.S.C.M.A. 202, 11 C.M.R. 202 (1953).
VI
The military judge, during instructions on findings, and as a part of his' instruction particularly relating to credibility, stated:
It’s really just a matter of you weighing the credibility of Commander Caruso and the system against your own common knowledge of the ways of the world, the operation of the ration control system here in Korea. (R. 98).
Appellant attacks the reference to the ration control system as error in that it involves a specialized area of knowledge not common to all military personnel. We find no error. It is sufficient that the matter be common knowledge in the “area in which the trial is held.” Paragraph 147a, Manual for Courts-Martial, United States, 1969 (Revised edition). The ration control regulations apply to all armed forces personnel in Korea and the ration control system is a factual matter “known at once with certainty by all reasonably intelligent people in the community without the need of resorting to any evidential data at all.” Weaver v. United States, 298 F.2d 496, 498 (5th Cir. 1962).
VII
During the presentencing phase of the trial, the military judge refused to admit a record of previous nonjudicial punishment because it was not signed by the commanding officer. Following instructions on sentencing, a court member asked whether there were any “previous Article ts [10 U.S.C.A. § 815].” The military judge responded:
MJ: Well you’re — obviously you’re not to consider anything in that nature. It would have been offered for you if it had any admissible element. I appreciate — that’s why we give the Government a chance to do so. Sometimes they have them and they’re not admissible, but you’re certainly not to infer that in this case.
No contention is made that the court members knew of a record of previous punishment, nor that one had been sought to be admitted, but appellant complains that the trial judge’s use of the pronoun “it” and his comment that sometimes they may exist and not be admissible, was enough to apprise the court of the existence of the record which had not been found admissible. We cannot agree. However, assuming the use of the word “it” to be error as claimed, the military judge’s response as a whole was sufficient to instruct the court not to infer the existence of any prior punishment.
VIII
Appellant contends the military judge erred in denying him an opportunity to obtain counsel. At an Article 39(a), 10 U.S.C.A. § 839(a) session, the trial defense counsel informed the military judge that just prior to coming into the courtroom, appellant had stated a desire to discharge his detailed defense counsel and assistant defense counsel. In the ensuing colloquy between the military judge and appellant, appellant was less than articulate, exceptionally equivocal and somewhat evasive as to why he wanted to discharge his detailed counsel, which of his other alternatives to choose, and what he might expect of another lawyer. He had made no prior request nor arrangements for any other counsel and had previously expressed no dissatisfaction with his detailed counsel, though it had been some 45 days since appellant had been informed of the charges. No motion for *642continuance was expressly made, and while the military judge treated the matter as such, no express denial of a continuance was stated. The military judge pointed out that it was too late to delay the trial any further, and appellant agreed to keep his detailed counsel. The granting or denial of a motion for continuance lies within the sound discretion of the military judge. United States v. Kinard, 21 U.S.C.M.A. 300, 45 C.M.R. 74 (1972); paragraph 58, Manual for Courts-Martial, United States, 1969 (Revised edition). The military judge should:
[Wjeigh carefully the merits of a motion to continue and if it appears reasonable that it is not made on frivolous grounds or solely for delay, the request should ordinarily be granted.3
Under the circumstances in this case, the military judge did not abuse his discretion. His treatment of this matter, comprising three pages of the record (R. 59-62) reflects a solicitous effort by the trial judge to determine whether appellant was sincere. We are convinced the request was frivolous.
IX and X
Assignments of error IX and X merit no discussion.
The findings of guilty and the sentence are affirmed.
. See Court-Martial Convening Orders numbered 2 and 16 in the Record of Trial at page 1.
. United States v. Saunders, 6 M.J. 731 (A.C.M.R.1978) (en banc).
. United States v. Nichols, 2 U.S.C.M.A. 27, 36, 6 C.M.R. 27, 36 (1952).