Defendant Ralph Ross appeals his conviction on a charge of illegal possession of an unregistered firearm in violation of the National Firearms Act (the Act). We affirm.
I. Background
On November 4, 1987, Special Agent Kevin Cronin of the Bureau of Alcohol, Tobacco and Firearms (ATF) searched Ralph Ross’ home and discovered over 50 guns. Apparently all the guns except a 1915 French Chauchat machine gun were properly registered. A plug of weld inside the machine gun’s chamber rendered it incapable of firing a shot. However, an ATF agent determined the gun could be restored to shoot within several hours by removing the weld. Ross claimed he did not know the gun was automatic, but did know it had been plugged. He further claimed the weapon previously had belonged to his father, who told him it was a replica. He never registered the weapon because he did not consider it to be a firearm.
A federal grand jury indicted Ross on two counts. Count 1 charged knowing possession of a firearm not registered to him in violation of 26 U.S.C. § 5861(d). Count 2 charged that he knowingly stored explosive material in a manner not in conformity with the Secretary of Treasury’s regulations in violation of 18 U.S.C. § 842(j). Ross pleaded guilty to Count 2. He proceeded to trial on Count 1 and was found guilty.
Ross appeals, and raises four issues. First, he alleges that his conviction constitutes an ex post facto punishment because he possessed the machine gun prior to enactment of the statute. Second, Ross contends the trial court abused its discretion by ordering him to reimburse the Federal Defender Program. Third, he alleges the district court incorrectly relied on factors which had not been proved beyond a reasonable doubt in determining his sentence. Finally, Ross argues that the district court incorrectly instructed the jury that the government was required only to prove Ross knew the weapon was a firearm in the general sense, rather than a machine gun.
II. Analysis
The first three issues are meritless. Although it is true that Ross possessed the machine gun prior to the 1986 amendments which made possession illegal, the conduct for which he was charged and convicted occurred on November 4, 1987, well after the amendments took effect. See, e.g., United States v. Poulos, 895 F.2d 1113, 1120 (6th Cir.1990), where the court rejected defendant’s argument that his conviction constituted ex post facto punishment because he obtained silencer kits prior to the 1986 amendments, but was charged with possessing those kits after the amendments took effect.
Ross further contends that the district court’s order to reimburse the Federal Defender Program for the cost of his court-appointed counsel was improper because he was unable at the time to make repayment. However, the evidence showed that Ross possessed the sole beneficial interest in a home valued at $149,600. On the day Ross was arraigned, he signed over his interest to Joe Waz, a friend of his. Ross continued to pay taxes on the property. Waz testified he was going to allow Ross to live in Waz’ home. The district court ruled that the circumstances of the transfer suggested that it was not a legitimate transaction. It found the transfer to be an effort to deceive the court, and as a result, the court ordered Ross to reimburse the program for the cost of his attorney. We find that the district court did not abuse its discretion in so finding. Cf. United States v. Durka, 490 F.2d 478 (7th Cir.1973) (trial court's determination whether defendant able to pay costs reviewed for abuse of discretion).
Ross also argues that factual determinations such as his role in the offense and his acceptance of responsibility are essential elements of the offense, and therefore must be proved beyond a reasonable doubt to a jury rather than by a preponderance of the evidence to a sentencing judge. However, “there is no Fifth Amendment *999right to a grand jury on the sentencing facts, nor any Sixth Amendment right to their determination by a petit jury, nor due process requirement that they be established beyond a reasonable doubt or even by clear and convincing evidence.” Buckley v. Butler, 825 F.2d 895, 903 (5th Cir.), cert. denied, 486 U.S. 1009, 108 S.Ct. 1738, 100 L.Ed.2d 201 (1987). Ross does not challenge whether the sentencing findings were supported by the evidence; he only argues that the findings were within the province of a jury to be determined beyond a reasonable doubt. Courts consistently have rejected this argument, and so do we.
The fourth and final issue is whether the court correctly instructed the jury that the government was required to prove only that Ross knew the weapon was a firearm in the general sense, as opposed to a machine gun.1 26 U.S.C. § 5861(d) provides that it “shall be unlawful for anyone to receive or possess a firearm which is not registered to him in the National Firearm Registration and Transfer record.” 26 U.S.C. § 5845 defines “firearm” to include:
(1) a shotgun having a barrel or barrels of less than 18 inches in length; (2) a weapon made from a shotgun if such weapon as modified has overall length of less than 26 inches or a barrel or barrels of less than 18 inches in length; (3) a rifle having a barrel or barrels of less than 16 inches in length; (4) a weapon made from a rifle if such weapon as modified has an overall length of less than 26 inches or a barrel or barrels of less than 16 inches in length; (5) any other weapon as defined in subsection E; (6) a machine gun; (7) any silencer ...; and (8) a destructive device.
Although the statutory definition of “firearm” is different than the general definition of firearm,2 we have previously held that the government need only prove that a defendant knew the weapon was a firearm in the general sense. See United States v. Gardner, 448 F.2d 617 (7th Cir.1971), relying on United States v. Freed, 401 U.S. 601, 91 S.Ct. 1112, 28 L.Ed.2d 356 (1971); United States v. Ranney, 524 F.2d 830 (7th Cir.1975). Those holdings dispose of Ross’ final contention.
In Gardner, we ruled that:
It is now clear that the Government was not required to prove that the defendant had knowledge of the registration provisions of the statute ... nor that defendant knew the physical characteristics of the weapon that rendered it subject to registration, in order to convict him____ Scienter is not an element in this cause.
The case of United States v. Freed ... is coneededly dispositive of this issue adversely to defendant’s contention on this appeal. A reading of this opinion by the Supreme Court will suffice.
448 F.2d at 619.
In Ranney, again relying on Freed, we held that
[t]he Government was not required to show that the Defendant had specific knowledge that the shotgun in question was not identified by a serial number or was less than the lawful length. Proof by the Government that the Defendant knew that he possessed a firearm in the general meaning of the term was sufficient to fulfill its burden on this point.
524 F.2d at 832 (citations omitted).
The interpretation to be given Freed has been a matter of some controversy. See, e.g., United States v. Anderson, 885 F.2d 1248 (5th Cir.1989) (en banc), overruling United States v. Vasquez, 476 F.2d 730 (5th Cir.), cert. denied, 414 U.S. 836, 94 S.Ct. 181, 38 L.Ed.2d 72 (1973). We believe our prior reading of Freed is correct, and that the principle behind Freed requires that we conclude the government met its burden here.
In Freed, the Supreme Court reversed a district court’s dismissal of an indictment *1000under § 5861. The district court had dismissed the indictment in part because of the “absence of an allegation of scienter.” 401 U.S. at 607, 91 S.Ct. at 1117. The Court held that the Act did not require any specific intent or knowledge that the firearm was unregistered, and concluded that “the only knowledge required to be proved was knowledge that the instrument possessed was a firearm.” Id. The Court went on to reject a due process challenge to the imposition of criminal liability with only that element of scienter, holding that this type of regulatory measure in the interest of public safety was probably premised on the notion that a defendant could hardly be surprised to discover that possession of the type of "firearm” described by the Act was not an innocent act. 401 U.S. at 609, 91 S.Ct. at 1118.
Anderson rejected our conclusion, believing that the statutory definition of “firearm” is so unorthodox that knowledge that something is a firearm in the lay sense is next to no knowledge. Hand grenades and “auto sears” (key parts in machine guns) are statutory firearms but not lay firearms; long rifles are lay firearms but not statutory firearms; only knowledge of the statutory terms yields scienter in such a world, the court concluded. Freed does not reject such an argument in terms; it was not presented to the Court as a possibility. But Freed does not support the holding of Anderson and similar cases.
Ross was charged with possessing an unregistered firearm. The statute, 26 U.S.C. § 5861(d), makes it a crime for anyone “to receive or possess a firearm which is not registered to him in the National Firearms Registration and Transfer Record.” The crime is possessing an unregistered firearm — not “knowingly” possessing an unregistered firearm, or possessing a weapon knowing it to be a firearm, or possessing a firearm knowing it to be unregistered. There is no knowledge component in § 5861(d). Ross’ proposal is not that we interpret a knowledge or intent requirement in § 5861(d); it is that we invent one. Yet § 5861(i), part of the same section of the 1968 Act, contains a scienter requirement. Ordinarily courts do not interpolate requirements of a kind that have been included in some subsections and omitted in their neighbors.
Courts now and again add mental elements to statutes lacking them, on the ground that Congress could not have meant strict liability. E.g., Liparota v. United States, 471 U.S. 419, 105 S.Ct. 2084, 85 L.Ed.2d 434 (1985); United States v. United States Gypsum Co., 438 U.S. 422, 438-43, 98 S.Ct. 2864, 2874-77, 57 L.Ed.2d 854 (1978); Morrissette v. United States, 342 U.S. 246, 72 S.Ct. 240, 96 L.Ed. 288 (1952). Traditional notions of punishment require consciousness of the acts being done. But some statutes create liability without knowledge, and the principal question in Freed was whether § 5861(d) is such a statute. The Court held that it is — at least to the extent the prosecution need not prove that the defendant was aware that the weapon was unregistered. Although the Court did not address whether the defendant needed to know that the item was a “firearm” in either lay or legal senses, the holding that § 5861(d) dispenses with any mental state concerning one element of the offense implies that mental states are unnecessary concerning the others in the same subsection.
Omission of a mental element is the norm for statutes designed to deal with inaction. Not registering your gun, not cleaning up your warehouse, United States v. Park, 421 U.S. 658, 95 S.Ct. 1903, 44 L.Ed.2d 489 (1975), and like “acts” are done without thinking. Often the omission occurs because of lack of attention. Requiring the prosecutor to prove a mental state in crimes of omission frequently precludes prosecution. Yet Congress may have sound reasons for requiring people to investigate and act, objectives that cannot be achieved if the courts add mental elements to the statutes.
Hardship there doubtless may be under a statute which ... penalizes the transaction though consciousness of wrongdoing be totally wanting. Balancing relative hardships, Congress has preferred to place it upon those who have at least the opportunity of informing themselves of *1001the existence of the conditions imposed for the protection of [the public] before sharing in illicit commerce, rather than to throw the hazard on the innocent public who are entirely helpless.
United States v. Dotterweich, 320 U.S. 277, 284-85, 64 S.Ct. 134, 138, 88 L.Ed. 48 (1943); see also United States v. Balint, 258 U.S. 250, 42 S.Ct. 301, 66 L.Ed. 604 (1922), which said of a regulatory statute: “Its manifest purpose is to require every person dealing in drugs to ascertain at his peril whether that which he sells comes within the inhibition of the statute, and if he sells the inhibited drug in ignorance of its character, to penalize him.”
Many persons must own old guns that may or may not be capable of automatic fire. Congress wants the automatic guns registered. That is going to happen only if the onus is on the owner. The approach of Gardner and Ranney requires the owner to investigate, and so leads to compliance with the law. The approach of Anderson converts ignorance into bliss. Why would any owner investigate, if all that could happen would be (a) burdensome registrations; or (b) forfeiture of the weapon if the defendant turns out to be ineligible to register it because of a prior conviction; or (c) a conviction for failure to register. Rational people would turn a blind eye, which would defeat the purpose of the statute.
“Ignorance of the law is no excuse” is one of the most venerable maxims of criminal law — not because most persons know the lav/, but because laws seek to change behavior. Compliance increases if ignorance is costly. Learning the law in order to comply must have rewards. If conviction is impossible unless the defendant knows the statutory scheme, then persons who take the first step toward compliance (learning the rules) will go to jail if they do not complete their compliance, while persons who take no steps at all toward compliance are immune from the law’s commands. That is not a sound approach as a norm.
Reading into the statute a requirement of knowledge that the object is a lay firearm, or a statutory firearm (the auto sear, for example), or a dangerous device apt to be regulated (hand grenades and bazookas, for example), makes sense. Knowledge of this kind is what puts people on inquiry. There is no sense in prosecuting someone who buys a cheesecake that, unbeknownst to him, contains hand grenades along with huckleberries. Nothing about a cheesecake calls for factual and legal research. Once a person knows that he possesses the sort of device that is extensively regulated, however, it serves the statutory scheme to cast on that person the risk of inaccuracy in evaluating facts and law. A majority of the appellate courts see things this way. United States v. DeBartolo, 482 F.2d 312, 316-17 (1st Cir.1973); United States v. Shilling, 826 F.2d 1365, 1368 (4th Cir.1987); Morgan v. United States, 564 F.2d 803, 806 (8th Cir.1977); United States v. Mittleider, 835 F.2d 769, 774 (10th Cir.1987); United States v. Gonzalez, 719 F.2d 1516, 1522 (11th Cir.1983). We accept the government’s concession that the prosecution must establish this kind of knowledge, and we adhere to the majority view that it need not prove more.
For all of the foregoing reasons, the judgment of the district court is
Affirmed.
. In addition to requiring the government to prove that the exhibit gun was possessed by Ross, was a machine gun, and was not properly registered, the given instruction also required "that the defendant knew that Government Exhibit Gun was a gun____"
. Webster’s Third New International Dictionary Unabridged defines a "firearm” as "a weapon from which a shot is discharged by gunpowder —usu. used only of small arms."