Appellant, David Michael Sterling, appeals from the judgment of sentence of the Court of Common Pleas of Erie County. On January 4, 1984, appellant was arrested and charged with three (3) counts of robbery, two (2) counts of receiving stolen property, three (3) counts of reckless en *272 dangerment, two (2) counts of corruption of minors, three (3) counts of criminal conspiracy, three (3) counts of possessing instruments of crime, one (1) count of simple assault and two (2) counts of terroristic threats. The charges related to appellant’s involvement with three (3) other males in a series of robberies. A carbon dioxide powered pellet gun owned by appellant was used during the course of the robberies. On May 17, 1984, appellant pled guilty to three (3) counts of robbery, one (1) count of corruption of minors and one (1) count of criminal conspiracy.
Upon petition of the Commonwealth, an evidentiary hearing 1 was held on June 12, 1984, to determine the applicability of 42 Pa.C.S. § 9712 to appellant’s sentence. The court determined that a carbon dioxide pellet gun was a “firearm” within 42 Pa.C.S. § 9712 and that the mandatory minimum sentence of imprisonment for the use of a firearm during the commission of a robbery was applicable. The court then sentenced appellant to concurrent terms of imprisonment of five (5) to ten (10) years on the robbery convictions and to concurrent probationary sentences on the conspiracy and corruption charges.
On appeal, the sole issue presented by appellant is whether a carbon dioxide pellet gun is a firearm within the meaning of 42 Pa.C.S. § 9712(e). He contends that the trial court erroneously determined that a carbon dioxide pellet gun was a firearm as defined in section 9712(e). Thus, he argues that the court erred in imposing the minimum five (5) year sentence of imprisonment mandated by section 9712 and, furthermore, that section 9712 is so vague as to render it unconstitutional. 2
We begin our analysis by examining section 9712 which provides as follows:
*273 § 9712. Sentences for offenses committed with firearms
(a) Mandatory sentence. — Any person who is convicted in any court of this Commonwealth of murder of the third degree, voluntary manslaughter, rape, involuntary deviate sexual intercourse, robbery as defined in 18 Pa. C.S. § 3701(a)(l)(i), (ii) or (iii) (relating to robbery), aggravated assault as defined in 18 Pa.C.S. § 2702(a)(1) (relating to aggravated assault) or kidnapping, or who is convicted of attempt to commit any of these crimes, shall, if the person visibly possessed a firearm during the commission of the offense, be sentenced to a minimum sentence of at least five years of total confinement notwithstanding any other provision of this title or other statute to the contrary.
(b) Proof at sentencing. — Provisions of this section shall not be an element of the crime and notice thereof to the defendant shall not be required prior to conviction, but reasonable notice of the Commonwealth’s intention to proceed under this section shall be provided after conviction and before sentencing. The applicability of this section shall be determined at sentencing. The court shall consider any evidence presented at trial and shall afford the Commonwealth and the defendant an opportunity to present any necessary additional evidence and shall determine, by a preponderance of the evidence, if this section is applicable.
(c) Authority of court in sentencing. — There shall be no authority in any court to impose on an offender to which this section is applicable any lesser sentence than provided for in subsection (a) or to place such offender on probation or to suspend sentence. Nothing in this section shall prevent the sentencing court from imposing a sentence greater than that provided in this section. Sentenc *274 ing guidelines promulgated by the Pennsylvania Commission on Sentencing shall not supersede the mandatory sentences provided in this section.
(d) Appeal by Commonwealth. — If a sentencing court refuses to apply this section where applicable, the Commonwealth shall have the right to appellate review of the action of the sentencing court. The appellate court shall vacate the sentence and remand the case to the sentencing court for imposition of a sentence in accordance with this section if it finds that the sentence was imposed in violation of this section.
(e) Definition of firearm. — As used in this section ‘firearm’ means any weapon (including a starter gun) which will or is designed to or may readily be converted to expel a projectile by the action of an explosive or the expansion of gas therein.
Appellant makes several arguments with respect to the interpretation of the definition of “firearm” in section 9712(e). First, he argues that since the case of
Commonwealth v. Schilling,
We reject appellant’s contentions. His interpretations disregard the clear and unambiguous statutory language contained in section 9712(e). “[W]hen the words of a statute are clear and free from all ambiguity, the letter of it is not to be disregarded.” 1 Pa.C.S. § 1921(b) (1964-1983 Supp.);
Commonwealth v. Patchett,
A carbon dioxide powered BB gun clearly fits within the ambit of section 9712(e). The section explicitly provides, “Definition of firearm. —As used in this section ‘firearm’ means any weapon (including a starter gun) which will or is designed to or may readily be converted to expel a projectile by the action of an explosive or the expansion of gas therein.” A carbon dioxide powered gun expels a projectile by the action of an explosive or the expansion of gas. Thus, there is no doubt that it is a firearm for purposes of section 9712 of the Sentencing Code. Further, we do not find appellant’s citation to the cases interpreting the definition of firearm under the Crimes Code persuasive. In section 9712(e) the introductory phrase, “as used in this section ‘firearm’ means”, evinces an awareness by the legislature that other definitions of firearm may exist, but that this particular definition is specifically applicable to section 9712 of the Sentencing Code.
Following the explicit statutory language of section 9712(e), we conclude that the trial court correctly determined that a carbon dioxide pellet gun is a firearm for purposes of section 9712.
Appellant also claims that the definition of firearm in section 9712(e) is contradictory because it first includes a starter gun, which appellant argues does not expel a projectile, and then proceeds to define a firearm in terms of weapons which expel projectiles. We find that this argument lacks merit. Section 9712(e) not only includes weapons which expel a projectile, but also encompasses “any weapon ... which ... may readily be converted to expel a projectile.” (emphasis added).
Appellant’s final contention is that the statute is unconstitutionally vague and violative of his due process rights in that it is impossible to determine what constitutes a firearm. A law is void on its face if it is so vague that persons of common intelligence must necessarily guess at
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its meaning and differ as to its application.
Fabio v. Civil Service Commission,
Reviewing the statute in light of the above principles, we find that the term “firearm” is clearly and specifically defined in section 9712 and requires no guess-work to determine its meaning. Accordingly, we find that section 9712 withstands appellant’s vagueness attack.
Judgment of sentence affirmed.
Notes
. The testimony from this evidentiary hearing is not included in the record on appeal.
. The Commonwealth contends that appellant waived this argument since he failed to file a motion to modify sentence. Although appellant alleges he filed a motion for reconsideration of sentence on June 22, 1984, there is no indication in the record that such motion was filed. Nevertheless, appellant's argument has not been waived. An
*273
issue raising the legality of a sentence cannot be waived by a failure to properly raise the issue in the trial court.
Commonwealth v. Cooke,
. 18 Pa.C.S. § 6101 et seq.