On January 31, 1975, appellant was convicted by a jury of violating the Controlled Substance, Drug, Device and Cosmetic Act.1 A timely motion in arrest of judgment was refused by the lower court, and sentence was pronounced. Appellant now questions the propriety of this conviction, raising several allegations of error. After careful review, we reject the appellant’s contentions, and affirm the judgment of sentence.
On March 21, 1974, a written complaint was filed against appellant charging him with selling a quantity of the controlled substance methamphetaminé (speed) to an *227undercover agent of the Pennsylvania State Police on two separate occasions. On June 10, 1974, a Grand Jury returned two bills of indictment against appellant, each charging him with possession and sale of a controlled substance. Although the case was listed for trial on October 7, 1974, trial was not held at that time because of the backlog of criminal cases in the court below. On November 27, 1974, the Commonwealth filed a timely petition for an extension of time for commencement of trial pursuant to Pa.R.Crim.P. 1100(c).2 In its petition, the Commonwealth asserted that it had exercised due diligence in bringing appellant to trial, attributing the responsibility for the delay to the judiciary. On December 9, 1974, the appellant filed an answer to the Commonwealth’s petition for extension of time, asserting that the Commonwealth had not exercised due diligence in prosecuting the case and requesting that the extension be denied “and the indictment dismissed for want of prompt prosecution.”3 On December 20, 1974 the lower court, after a hearing on the record, granted the Commonwealth an extension of time and trial commenced on January 31, 1975. With this extension, appellant’s trial commenced 45 days beyond the 270 day period contained in Rule 1100(a)(1).
Appellant first contends that his right to a speedy trial was denied in that he had not been brought to trial within 270 days from the date the criminal complaint was filed against him. We disagree. In the opinion filed by *228the court below, Judge Lowe related the positions as presented by both appellant and the Commonwealth, and concluded:
“Clearly, the Commonwealth did not procrastinate in obtaining the defendant’s indictments, nor did it solicit or request a continuance at any time. The Commonwealth’s swift action afforded the administrative arm of this Court more than six months during which it could schedule a trial that would comport with Rule 1100. The case would have been tried on the 200th day had it not fallen victim to this county’s prodigious criminal caseload. Nevertheless, it is significant that the Commonwealth’s petition seeking a time extension was filed as soon as it became apparent that the schedule prescribed by Rule 1100 could not be satisfied. The petition was filed well before ‘the expiration of the period for commencement of trial’ as mandated by the Rule. This Court knows of no avenue or course which the Commonwealth could have pursued to expedite the prosecution of this case and it should not be held accountable for delays beyond its control.”
In Commonwealth v. Mayfield, 469 Pa. 214, 220, 364 A.2d 1345 (1976), the Supreme Court, in reversing the decision of this court,4 stated inter alia:
“The Superior Court, concluding that rule 1100 was intended to promote prompt action by the courts as well as by the prosecution, held that delays attributable to court administration could never justify an extension under rule 1100(c). The rule, however, was not intended to create such an inflexible result. This Court is aware that, despite diligent efforts by the trial courts, cases may arise when a trial of a defendant cannot be held within the prescribed period. In such circumstances, the policies which prompted the adop*229tion of rule 1100 would not be served by disallowing a reasonable, limited extension specifying ‘the date or period within which trial shall be commenced.’ Pa.R. Crim.P. 1100(c). The rule recognizes that ‘due diligence’ is the most that should be demanded from the prosecutor and that if despite such efforts, he cannot prepare for trial within the prescribed period, an extension is permissible. No more rigid result under our present rule is justified when the inability of a trial court to proceed within the prescribed period is at issue.”
In Commonwealth v. Shelton, 469 Pa. 8, 16-17, 364 A.2d 694 (1976), the Supreme Court specifically and candidly stated:
“The ‘Commonwealth’ in the context of the Rule clearly refers to prosecutorial officers and not to the judiciary. Literally read, the Rule quite simply does not attempt to solve the problem of eliminating delay due to the judiciary; rather, it attempts to eliminate delay due to lack of due diligence on the part of prosecutorial officers. Furthermore, if ‘judicial delay’ does not justify an extension, then in a situation where because of the unavailability of a judge or a court before whom to commence trial at a time prior to the expiration of the mandatory period, the Commonwealth despite the exercise of all due diligence would be unable to effectuate a prosecution. Such a result would render the due diligence exception a nullity We therefore expressly disapprove the dicta in the majority opinion of the Superior Court and rule that ‘judicial delay’ may justify the granting of an application for an extension when timely filed.”
It is clear from the above statements of current and controlling case law, as applied to facts of the instant case, that the Commonwealth has established that it exercised due diligence and that the lower court’s continuance *230based upon the lower court’s criminal cases backlog was justified.
The appellant also contends in a pro se brief that his trial counsel was ineffective when he failed to call a prison inmate as a witness to impeach the testimony of the Commonwealth’s witnesses. We find this contention without merit.5 “[O]ur inquiry ceases and counsel’s assistance is deemed constitutionally effective once we are able to conclude that the particular course chosen by counsel had some reasonable basis designed to effectuate his client’s interests.” Commonwealth ex rel. Washington v. Maroney, 427 Pa. 599, 604, 235 A.2d 349, 352 (1967). The record clearly indicates that trial counsel was reasonable in not placing appellant’s proposed witness on the stand.6
Accordingly, the judgment of sentence of the court below is affirmed.
HOFFMAN, J., concurs in the result. PRICE, J., files a concurring opinion.. Act of April 14, 1972, P.L. 233, No. 64, I 1 (35 P.S. § 780-101) et seq.
. Pa.R.Crim.P. 1100(c) provides in pertinent part:
“At any time prior to the expiration of the period for commencement of trial, the attorney for the Commonwealth may apply to the court for an order extending the time for commencement of trial. . . . Such application shall be granted only if trial cannot be commenced within the prescribed period despite due diligence by the Commonwealth.”
. The concurring opinion argues that appellant waived his right to a speedy trial by failing to file a petition for dismissal pursuant to Pa.R.Crim.P., Rule 1100(f). This argument was rejected by our court in Commonwealth v. Sprankle, 241 Pa.Super. 298, n. 1, 361 A.2d 385 (1976).
. Commonwealth v. Mayfield, 239 Pa.Super. 279, 362 A.2d 994 (1976).
. See Commonwealth v. Dancer, 460 Pa. 95, 331 A.2d 435 (1975); Commonwealth v. Twiggs, 460 Pa. 105, 331 A.2d 440 (1975).
. Appellant also argues that the evidence presented at trial was insufficient to prove him guilty beyond a reasonable doubt. However appellant did not raise this issue in his post-trial motions, so the issue is waived. Commonwealth v. Bronaugh, 459 Pa. 634, 331 A.2d 171 (1975).