Defendant-Appellant Mark Stephen Forrester (Forrester) appeals his conviction and sentence for conspiracy to manufacture and distribute ecstasy in violation of 21 U.S.C. §§ 846 and 841(a)(1). Forrester and his codefendants operated a large ecstasy laboratory that was under surveillance for over a year before being closed by law enforcement authorities. Forrester represented himself at trial, and was convicted and sentenced to 30 years in prison. We previously remanded Forrester’s case based on our finding that Forrester unintelligently waived his right to counsel. On remand, Forrester pleaded guilty, and was again sentenced to 30 years. He raises five issues on appeal. First, he claims that the district court erred by failing to allow him to argue that ecstasy should be categorized as a Schedule III, rather than a Schedule I, controlled substance, and that 21 U.S.C. § 841(b) is unconstitutional. Second, he asserts that he has a present right to accept the government’s original plea offer — which he originally rejected— because he had been misadvised by the district court concerning his maximum sentence exposure. Third, Forrester al *976 leges that his conspiracy indictment was unconstitutionally vague. Fourth, he argues that the district court erred in denying his motion to suppress all fruits of the wiretap. Finally, he claims that the district court erred in sentencing him to 30 years in prison.
We affirm Forrester’s conviction, but vacate his sentence, and remand for further proceedings consistent with this opinion.
FACTS, PRIOR PROCEEDINGS, AND JURISDICTION
Law enforcement authorities conducted a lengthy investigation into an elaborate conspiracy to manufacture ecstasy. Investigators tracked the conspiracy for over a year using an array of surveillance techniques. They traced chemical purchases, used confidential informants to infiltrate the operation, followed Forrester to Stockholm where he met with chemists, and discovered a clandestine laboratory in Escondido, California. Agents raided the lab and seized large volumes of ecstasy and precursor chemicals.
In October 2001, Forrester and his codefendants were charged with conspiracy to manufacture and distribute ecstasy. On October 23, 2002, the district court held a Faretta hearing to determine whether Forrester was competent to represent himself. The judge found that he was but, during the hearing, the district judge misinformed Forrester that he was facing a sentence of 10-years-to-life, when he was actually facing a sentence of 0-to-20 years. Forrester represented himself from that point in the proceedings until his initial appeal.
On July 3, 2003, the government approached Forrester and his codefendant Dennis Alba (Alba) with a deal. They informed Forrester and Alba that if they did not both plead guilty that same day, the government would file an enhancement pursuant to 21 U.S.C. § 851 requesting that Forrester’s maximum sentence be increased from 20 to 30 years. Forrester and Alba both declined the offer and, on July 18, 2003, a jury found Forrester guilty. He was sentenced to 30 years on May 26, 2003. Forrester appealed on May 31, 2003. We found that Forrester had unknowingly and unintelligently waived his right to counsel because the district judge misinformed him regarding his maximum sentence,
United States v. Forrester,
We have jurisdiction under 28 U.S.C. § 1291 and 18 U.S.C. § 3742.
STANDARDS OF REVIEW
In addressing Forrester’s first claim regarding the classification of ecstasy as a Schedule I substance, we review de novo the district court’s construction or interpretation of a statute.
See Beeman v. TDI Managed Care Sews., Inc.,
Forrester next argues that his failure to accept the plea was involuntary. The voluntariness of a guilty plea is subject to de novo review.
See United States v. Gaither,
Forrester also contests the sufficiency of the conspiracy indictment, which we review de novo.
United States v. Berger,
We next address a number of issues with regard to the wiretap application. We review de novo the district court’s interpretation of the wiretap stat
*977
ute.
United States v. Luong,
Finally, Forrester raises three sentencing issues. We review ex post facto challenges to sentencing decisions de novo.
United States v. Ortland,
DISCUSSION
Forrester appeals his conviction and sentence. First, he argues that ecstasy should be classified as a Schedule III substance, and that his maximum sentence must be determined by a jury. Second, he asserts that misinformation regarding his maximum sentence rendered his rejection of a plea deal unintelligent. Third, he claims that his conspiracy indictment was unconstitutionally vague. Fourth, he alleges that the district court erred in denying his motion to suppress all fruits of the wiretap. Finally, he claims that his sentence was improper.
I. Controlled Substance Scheduling
The Controlled Substances Act (CSA), 21 U.S.C. § 801 et seq., establishes five categories or “schedules” of controlled substances. Ecstasy has been classified as a Schedule I controlled substance since March 23, 1988. See 53 Fed.Reg. 5156 (Final Rule dated Feb. 22, 1988 — Schedules of Controlled Substances; Scheduling of 3, 4 Methylenedioxymethamphetamine (MDMA) into Schedule I of the Controlled Substances Act; Remand). Violations involving Schedule I substances carry more severe penalties than those in Schedule III because the drugs have a high potential for abuse and no generally accepted medical benefits. 1 21 U.S.C. § 812(b)(1). Forrester claims that the district court erred by failing to allow him to present a defense that ecstasy should be categorized as Schedule III rather than as Schedule I, which defense, had it been allowed, would have subjected him to a lower maximum penalty, as set forth in 21 U.S.C. § 841(b)(1)(D). Alternatively, he argues that § 841(b) violates the Fifth and Sixth Amendments because it allows a maximum sentence to be determined by a fact not found by the jury.
A. Collateral Attack on a Scheduling Order
The Attorney General (AG) has designated ecstasy as a Schedule I controlled substance under the CSA. 2 The *978 CSA allows the AG to schedule a substance on a temporary basis when doing so is “necessary to avoid an imminent hazard to the public safety.” 21 U.S.C. § 811(h). 3
Forrester argues that the Schedule III definition more accurately describes ecstasy than does the one in Schedule I, and that “the scheduling of ecstasy has been questioned by the medical community.” Forrester further argues that denying him the opportunity to argue that ecstasy should be designated a Schedule III controlled substance violates
Touby v. United States,
In
Touby,
the petitioners were convicted of conspiring to manufacture “Euphoria,” a designer drug that was temporarily placed under Schedule I.
The concurring opinion in
Touby
emphasized that “the opportunity of a defendant to challenge the substance of a temporary scheduling order in the course of a criminal prosecution is essential to the result in this case” and that Congress “did not intend to foreclose review in the enforcement context.”
Id.
at 169-70,
The Eleventh Circuit, the only circuit to have previously addressed this issue to date, came to the same conclusion.
United States v. Carlson,
Forrester argues that, in other situations, Congress has been explicit about not permitting collateral attacks at trial. For example, 8 U.S.C. § 1189(a)(8) states:
If a designation under this subsection has become effective under paragraph (2)(B) a defendant in a criminal action or an alien in a removal proceeding shall not be permitted to raise any question concerning the validity of the issuance of such designation as a defense or an objection at any trial or hearing.
Section 1326(d) contains a similar provision in the deportation context. However, the evidence that Congress has, at times, taken a more proactive stance toward controlling collateral challenges is not sufficient to overcome our reading of Touby, and the persuasive reasoning of our sister circuit, to the effect that collateral attacks are not permitted in criminal cases involving permanent scheduling orders.
We hold that substantive collateral attacks on permanent scheduling orders are impermissible in criminal cases where defendants’ sentences will be determined by those scheduling orders. Accordingly, we conclude that the district court did not err in denying Forrester’s motion for an evidentiary hearing on the issue.
B. Constitutionality of 21 U.S.C. § 841(b)
Forrester also argues that 21 U.S.C. § 841(b)(1)(C) violates the Fifth and Sixth Amendments, as construed in
Apprendi v. New Jersey,
The Supreme Court held in
Apprendi
that “[o]ther than the fact of a prior conviction, any fact that increases the penalty for a crime beyond the prescribed statutory maximum must be submitted to a jury, and proved beyond a reasonable doubt.”
In both
Apprendi
and
Buckland,
the judges made improper findings of
conduct
(sale of a particular drug and engaging in hate speech, respectively) by a preponderance of the evidence. The respective courts held that those findings should have been made by a jury beyond a reasonable doubt.
See Buckland,
II. Rejected Plea Offer
On October 23, 2002, Forrester waived his right to counsel under
Faretta v. California,
On July 3, 2003 (five days before trial), the government extended a plea offer to Forrester and Alba. The government told Forrester that if both he and Alba accepted the “package deal,” Forrester could limit his exposure to 20 years. The government stated that if the plea offer was not accepted by 2:00 pm that same day, it would file a sentence enhancement pursuant to 21 U.S.C. § 851. The offer was not accepted by either Forrester or Alba, and the government filed the § 851 enhancement, thereby enhancing Forrester’s maximum penalty from 20 to 30 years. See 21 U.S.C. § 841(b)(1)(C).
The case proceeded to trial and Forrester was convicted, and sentenced to the maximum of 30 years. We reversed, finding a defective waiver of counsel due to the district court’s erroneous sentencing advisement during the
Faretta
hearing.
Forrester I,
Well, the government has the right to file anything they think, any conduct or convictions they think they can prove. With regard to misadvising him of the maximum penalty, you are absolutely correct I did misadvise him. No question about that.
In any event, I don’t think there is anything inappropriate for the government having filed that 851 allegation. I understand your honor [sic] position, but your request that I have it stricken or dismissed is denied.
Forrester then pleaded guilty and was sentenced (again) to the 30-year maximum. Forrester alleges that the district court erred by failing to dismiss the § 851 *981 sentence enhancement due to its prior sentencing miscalculation, thereby depriving him of the opportunity to make a knowing and intelligent decision to accept an earlier plea offer that did not include the enhancement.
Federal Rule of Criminal Procedure 11(b) states that the court must hold a hearing and inform a defendant of, and determine that he understands, “any maximum possible penalty, including imprisonment, fíne, and term of supervised release” and “any mandatory minimum penalty,” before it accepts his guilty plea (the plea hearing). Fed. R. Crim. P. 11(b)(1)(H) & (I). A failure to ensure that a defendant understands his range of exposure may violate the requirement that a guilty plea be “knowing and voluntary.”
See, e.g., Tanner v. McDaniel,
“[Tjhere is no constitutional right to plea bargain.” Weatherford v. Bursey,
Forrester argues that, once a plea offer has been made, a defendant has a right to be accurately informed about his potential exposure before deciding to reject it. He relies on
Nunes v. Mueller,
a habeas case in which an attorney misinformed the defendant that he had received a plea offer for 22 years as opposed to 11 years.
Nunes
was based on the well-founded constitutional right to effective assistance of counsel.
Id.
at 1051-1054. For
Nunes
to apply here, we would have to find that Forrester suffered a similar unconstitutional deprivation of rights that tainted his rejection of the plea offer. We decline to do so on these facts. Though a defendant may have a right to voluntarily and intelligently reject a plea offer, we need not reach that question in this case because any error was harmless.
See Bains v. Cambra,
First, Forrester was offered a “package deal” with Alba. Because Alba rejected the *982 deal, Forrester could not unilaterally have accepted it even if he had been aware of his actual potential sentence. Indeed, Alba had no incentive to accept the plea, as the threatened enhancement did not affect his exposure because he already faced life in prison on a continuing criminal enterprise count.
Second, Forrester’s maximum and minimum possible sentences were
overstated.
Forrester was offered a 20-year cap on his sentence when he thought he faced 10-to-life if he went to trial. In rejecting the offer to cap his exposure at 20 years, he risked receiving what he thought was a life sentence for the potential benefit of being acquitted. He now claims that, had he known that he actually faced a potential sentence of 0-to-30 years (with the enhancement), he would have foregone risking the 30-year maximum and accepted the deal to cap his exposure at 20 years. In other words, he says he was willing to risk receiving 10-to-life for the possibility of acquittal, but would not have been willing to take his chances at 0-to-30. We find this argument counterintuitive. Though it is certainly possible that a misinformed defendant may reject a plea that he otherwise would have taken, that was undoubtedly not the case here.
Cf. United States v. Stubbs,
III. Sufficiency of the conspiracy indictment
Forrester alleges that his indictment for conspiracy was insufficient. The second superseding indictment at issue reads:
Beginning at a date unknown to the grand jury and continuing up to and including October 18, 2001, within the Southern District of California, and elsewhere, [Forrester and 18 other named defendants], all charged elsewhere, did knowingly and intentionally conspire together and with each other and with other persons known and unknown to the grand jury to manufacture and distribute a controlled substance, to wit, 3, 4 Methylenedioxyamphetamine
(“MDA”), commonly known as “ecstasy”, a Schedule I Controlled Substance, in violation of Title 21, United States Code, Sections 846 and 841(a)(1).
Forrester filed a motion to dismiss for deficiency, and the district court denied the motion without explanation.
An indictment “must be a plain, concise and definite written statement of the essential facts constituting the offense charged.” Fed. R. Crim. P. 7(c)(1). “An indictment is sufficient if it (1) contains the elements of the offense charged and fairly informs a defendant of the charge against him which he must defend and (2) enables him to plead an acquittal or conviction in bar of future prosecutions for the same offense.”
United States v. Lazarenko,
Forrester contends that the indictment is insufficient because it fails to specify a beginning date for the conspiracy, thereby possibly subjecting him to double jeopardy. However, although an indictment cannot be completely open-ended,
see United States v. Cecil,
In addition, uncertainty regarding a conspiracy’s beginning and ending dates does not render an indictment fatally defective so long as overt acts alleged in the indictment adequately limit the time frame of the conspiracy.
United States, v. Lay-kin,
IV. The Wiretap
On February 5, 2001, the government submitted an initial application for a 30-day wiretap order. The application contained a 53-page affidavit by Special Agent Robert Aguirre, and a separate 3-page affidavit (Exhibit C) that was filed under seal. The district judge approved the wiretap on the same day. Forrester challenges the wiretap on several grounds. First, he claims that he was entitled to access the redacted contents of Exhibit C. Second, he claims that the wiretap application failed to comply with the “necessity” requirement of the statute. Third, he claims that the wiretap violated the Fourth Amendment.
A. Right to View the Redacted Affidavit
Exhibit C provided information about a confidential informant referred to as “CS.” Federal Rule of Criminal Procedure 16 governs government disclosure of information, stating:
Upon a defendant’s request, the government must permit the defendant to inspect and to copy or photograph books, papers, documents, data, photographs, tangible objects, buildings or places, or copies or portions of any of these items, if the item is within the government’s possession, custody, or control and:
(i) the item is material to preparing the defense;
(ii) the government intends to use the item in its case-in-chief at trial; or
(iii) the item was obtained from or belongs to the defendant.
*984 Fed. R. Crim. P. 16(a)(1)(E). In addition, 18 U.S.C. § 2518 states that the fruits of a wiretap may not be used in court unless a copy of the court order and the wiretap application are furnished to each party:
The contents of any wire, oral, or electronic communication intercepted pursuant to this chapter or evidence derived therefrom shall not be received in evidence or otherwise disclosed in any trial, hearing, or other proceeding ... unless each party ... has been furnished with a copy of the court order, and accompanying application, under which the interception was authorized or approved.
Id. § 2518(9).
The district court denied Forrester’s motion for specific discovery of Exhibit C. It found that the items sought were not discoverable under Rule 16 because they were not material to the presentation of the defense. The question is whether 18 U.S.C. § 2518, which mandates disclosure of the wiretap application, allows the government to redact some information in the application. This is a question of first impression in our circuit, though one that has been addressed by other courts.
Forrester asks us to adopt the reasoning of the district court in
United States v. Arreguin,
We find the reasoning in
United States v. Danovaro
more persuasive.
The preamble to Exhibit C states: “As noted in Exhibit B, none of the information set forth in this supplemental pleading is being submitted to establish either probable cause or necessity for the requested wiretap.” The rest of the two-and-a-half page document is redacted. Exhibit B explains that
[d]ue to the nature of the CS’s cooperation with law enforcement officers and the risk to the safety of the CS if his/her identity is disclosed, I am submitting details regarding the CS’s background and knowledge in [Exhibit C], For the purpose of establishing probable cause for the requested wire intercept, I am not submitting the facts and circumstances in Exhibit C; rather, I am providing the Court with the information in Exhibit C to substantiate my belief that the CS is a reliable source of information and, as addressed below, to show the limitations of the CS with respect to law enforcement’s ability to achieve the goals of this investigation without the requested wiretap authorization.
Because, as discussed below, the unredacted parts of the wire-tap application were more than sufficient to establish necessity, we find that the district court did not err in denying Forrester’s motion for specific discovery.
B. § 2518’s Necessity Requirement
Under 18 U.S.C. § 2518(3)(c), a judge may authorize a wiretap if the application demonstrates that “normal investigative procedures have been tried and have failed or reasonably appear to be unlikely to succeed if tried or to be too dangerous.” This “necessity requirement” is intended to ensure that wiretapping is not resorted to in situations where traditional investigative techniques would suffice to expose the crime.
United States v. Kahn,
*986 The district court authorized the wiretap after finding that it was necessary. The 72-page wiretap application extensively detailed target subjects, the basis of information, the MDA manufacturing process, the facts establishing probable cause, and the inadequacy of traditional investigative techniques. The latter section, spanning 20 pages, explained how the use of confidential informants and undercover officers, physical surveillance, pen registers, telephone rolls, search warrants, interviews, grand jury subpoenas, and trash searches had proven inadequate.
Forrester argues that the application did not provide a full and complete statement regarding the government’s investigatory techniques, and therefore failed to meet the necessity requirement. In fact, the wiretap application contained a full and complete statement of the facts. It described in great detail the entire course of the investigation. It described the target subjects and their backgrounds, the numerous sources of information (DEA & Bureau of Narcotics Enforcement agents, federal, state, and local drug task force officers, and the Swedish National Criminal Investigative Department, among others), the MDA manufacturing process, Forrester’s trips to Sweden to visit known ecstasy manufacturers, specific chemical orders and shipments, efforts to follow Forrester to Sweden and details of his activities there, and an extensive analysis of the pen register and toll information for the target telephone. To demonstrate that traditional investigative techniques were insufficient, the affidavit described the use (and lack of success) of confidential informants, undercover officers, physical surveillance (including stationary cameras), pen registers, search warrants, interviews, and trash searches.
Based on this full and complete statement, the district court’s necessity finding was not an abuse of discretion. The application carefully explains why traditional investigative techniques would not have enabled officers to achieve the goals of the investigation. For instance, it noted that one of the confidential informants knew of a clandestine lab but could not get the defendants to disclose its location. There was also some evidence that the confidential informant (Cl) was receiving incorrect information, and as a drug buyer, the Cl was not privy to key information about the defendants’ operation. As another example, the application noted that the use of physical (camera and video) surveillance had enabled the government to identify some target subjects, confirm that Forrester traveled to Sweden, and confirm a meeting between Forrester and Alba. However, it could not establish the identities of all coconspirators or provide evidence of the purpose and content of conspiratorial meetings. The application also listed specific investigative goals not yet achieved through the use of conventional techniques, including the identification of all coconspirators of the target subjects, the manner in which they were laundering the proceeds, and the locations where they were manufacturing and distributing the ecstasy.
Forrester’s reliance on
United States v. Gonzalez, Inc.,
*987
The necessity requirement was intended to ensure that wiretaps are not used as the initial step in a criminal investigation.
United States v. Giordano,
C. The Fourth Amendment Wiretap Claim
Forrester argues that, even if the necessity requirement was met, the application violated the Fourth Amendment standard set forth in
Berger v. New York,
because of a lack of exigent circumstances.
[The wiretap statute] permits uncontested entry without any showing of exigent circumstances. Such a showing of exigency, in order to avoid notice would appear more important in eavesdropping, with its inherent dangers, than that required when conventional procedures of search and seizure are utilized.
Id.
at 60,
Furthermore, the Supreme Court has routinely acknowledged that § 2518 “prescribes the procedure for securing judicial authority to intercept wire communications,”
Giordano,
Y. Sentencing
A. Temporary Amendment to the Ecstasy Act
The November 2000 sentencing manual provided that one gram of MDA was the equivalent of 50 grams of marijuana. U.S.S.G. § 2D1.1 (2000). The Ecstasy Anti-Proliferation Act of 2000 (Ecstasy Act), contained in Pub.L. 106-310, directed the Sentencing Commission to increase penalties for ecstasy. Pub.L. 106-310 §§ 3663(a), 3664. Accordingly, the Sentencing Commission promulgated a temporary amendment to § 2D1.1 that increased this ratio to 500:1, effective retroactively as of May 1, 2001. The district court relied on this temporary amendment in setting the base offense level. Forrester argues that subjecting him to a heightened sentence pursuant to the temporary amendment violated the ex post facto clause of the Constitution.
1. The end date listed in the indictment
The indictment alleged that the conspiracy continued until October 18, *988 2001. The indictment was reproduced in full in the plea agreement. The plea’s “Factual Basis” section mentioned only a beginning date, stating that “[i]n or about November, 2000, ... Forrester entered into an agreement with Alba, and others, to manufacture and distribute” ecstasy.
We have declined to treat “guilty pleas as admitting factual allegations in the indictment not essential to the government’s proof of the offense.”
United States v. Cazares,
2. Effective Date of the 500:1 Ratio
Forrester also argues that even if the October 18, 2001 end date can be used for sentencing, the increased ratio of 500:1 did not become effective until November 1, 2001, at the earliest, because the temporary amendment was invalid. We agree that the temporary amendment’s retroactivity was invalid, but hold that the amendment became effective on June 6, 2001 when it was initially published.
In
United States v. DeLeon,
the Eighth Circuit considered whether the referenced temporary amendment violated the Administrative Procedures Act (APA).
The court’s reasoning was two-fold. First, § 553(d) of the APA ordinarily requires that a rule be published at least 30 days prior to its effective date and, upon a showing of good cause, permits a rule to take effect immediately upon publication.
Id.
Therefore, even if the good cause exception applies, the earliest effective date would be the June 6 publication date. Second, the court considered whether the amendments could be retroactive to May 1. Agencies cannot adopt retroactive regulations “unless that power is conveyed by Congress in express terms.”
Bowen v. Georgetown Univ. Hosp.,
Therefore, if on remand the district court finds by a preponderance of the evidence that the conspiracy continued until at least October 2001, then the enhanced 500:1 ratio was appropriately applied to Forrester’s sentence because it ended after June 6 2001, when the enhanced ratio became effective.
B. Estimating Ecstasy Quantities
Under the Sentencing Guidelines, “[wjhere there is no drug seizure or the amount seized does not reflect the scale of the offense,” a district court may estimate the quantity of the drug and may consider “the size or capability of any laboratory involved.” U.S.S.G. § 2D1.1 cmt. n. 12;
see also United States v. Putney,
1. Insufficient Findings as to the Amount of Ecstasy Involved
Forrester claims that the district court failed to make specific findings regarding the parties’ factual disputes about the amount of ecstasy involved, in violation of Federal Rule of Criminal Procedure 32. In
United States v. Carter,
we held that “[f]or each disputed fact upon which the district court intends to rely in imposing the sentence, the district court must make an explicit factual finding that resolves the dispute [or] must clearly state that the disputed fact was not taken into account....”
Here, the district court held a lengthy hearing in which the government presented evidence about the estimated yield, which led to an extensive exchange between the parties regarding the chemist’s theoretical yield estimate, the PSR, the reliability of Alba’s statement corroborating that estimate, and Alba’s business plan indicating that the goal of the conspiracy was to manufacture 440 kilos of ecstasy per month. The district court must rule on each of these disputed facts individually. See id. at 866-67. In doing so, the court ensures meaningful appellate review and avoids “the unfairness that would result to a defendant if prison or parole officials were to rely on false allegations or uncorrected reports.” Id. at 866.
The district judge calculated a base level offense of 38 based on the “testimony of the chemist at trial, the grafts that were seized from the lab up there, and just tangentially the fact that the Ninth Circuit actually upheld the same base offense level in Mr. Alba’s case.” 9 Although the sen- *990 fencing hearing was very thorough, a specific finding was not made as to the amount of ecstasy involved in the conspiracy. 10 While a base offense level of 38 may well have been reasonable, that particular level applies to a range of quantities beginning at 60 kilos, so it cannot be used as a proxy for an exact finding as to the amount of ecstasy involved in this case.
Since this case is being remanded for additional findings as to the end date of the conspiracy, we also direct that the district court make explicit findings on all contested issues raised at sentencing, the most important of which is the amount of ecstasy involved in the conspiracy.
2. The Amount of Ecstasy Involved
Although the district court did not make explicit findings as to the amount of ecstasy involved, it necessarily relied on some implicit finding of quantity in determining the base offense level. There are three criteria for approximations of drug quantity.
United States v. Kilby,
First, the government is required to prove the approximate quantity by a preponderance of the evidence ... which means that the district court must conclude that the defendant is more likely than not actually responsible for a quantity greater than or equal to the quantity for which the defendant is being held responsible. Second, the information which supports an approximation must possess sufficient indicia of reliability to support its probable accuracy. Third, since the sentence depends in large part upon the amount of drugs ... and approximation is by definition imprecise, the district court must err on the side of caution in approximating the drug quantity.
Id. (internal quotation marks omitted).
We have repeatedly held that a court must “err on the side of caution” when estimating drug quantity,
Chase,
*991 Here, the government’s expert, DEA chemist Skinner, testified that one of his calculations was a maximum theoretical yield of 183.6 kilos of ecstasy. In Chase, the government’s expert had “quite candidly admitted that his calculation was a maximum theoretical yield,” an approach that this court found “unreliable as a method of estimating how much methamphetamine [the defendant] produced.” Id. However, Skinner also testified that “there is a wide range in the yield ... from lab to lab,” and that he had also calculated a substantially lower “actual yield” of 63.1 kilos of ecstasy based upon the quantities of seized materials. The actual yield assumed that Forrester’s lab could achieve a “conservative” 50% yield at each reaction state from the seized precursor chemicals, instead of the 100% yield assumed in the TMY calculation. The chemist based his estimates to some extent on his conversation with Forrester’s co-conspirator Alba. The district judge indicated that he had calculated the base offense level of 38 relying on, among other things, the testimony of the government’s chemist, but did not specify on which of the two estimates he was relying.
Since the district court did not make any explicit findings about the amount of ecstasy involved when it imposed a base offense level of 38, we need not reach the question of whether the court relied on an improper method of calculating the amount of ecstasy. However, we note that when there are two reasonable methods of calculation, the district court should select the measure that brings the lesser punishment,
Hardy,
Forrester also claims that his sentence was substantively unreasonable under 18 U.S.C. § 3553(a), but we decline to reach this issue because we are remanding for additional findings and resentencing.
CONCLUSION
For the foregoing reasons, we AFFIRM Forrester’s conviction, VACATE his sentence, and REMAND for additional findings and resentencing in conformity with this opinion.
Notes
. The maximum Schedule I and III sentences for offenses committed by a defendant with a prior drug conviction are 30 years and 10 years, respectively. See §§ 841(b)(1)(C), (D).
. Congress delegated the authority to schedule drugs to the AG, 21 U.S.C. § 811(h) and the AG, in turn, has delegated the authority to update the CSA schedules to the Drug Enforcement Agency (DEA). 28 C.F.R. § 0.100. However, the legitimacy of this delegation is not at issue here; accordingly, for purposes of this opinion, we attribute scheduling decisions to the AG.
. This allows the AG to bypass, for a limited time, the lengthy procedure required for permanent scheduling and thus enables the government to respond more quickly to dangerous new drugs. Temporary scheduling orders remain valid for one year. Section 811(h)(6) provides that a temporary order is not subject to “judicial review.” Id.
. Forrester pleaded guilty and thus waived his right to a jury trial. His guilty plea thus stands in the place of a jury's findings.
See United States v. Banuelos,
. See supra note 2.
. In
Forrester I,
we rejected a similar argument that the district court's overstatement made Forrester less likely to waive counsel.
. The
Arreguin
court, in contrast, held that the statutory disclosure requirement of § 2518(9) always trumps the informant privilege set forth in
Roviaro. See Arreguin,
. At least two other district courts have also found
Danovaro
more persuasive than
Arreguin. See United States v. Coles,
No. 05-440,
. The finding that “the Ninth Circuit actually upheld the same base offense level” for Alba *990 was erroneous. That issue was not raised on appeal in Foirester I. This error demonstrates the importance of having each finding explained so that its merits can be assessed later.
. The lack of a specific finding as to the amount of ecstasy has, in turn, hampered us in determining whether the appropriate drug estimation method was used.
. Forrester observes that the TMY result is particularly suspect in this case because, "according to the government, the conspiracy was only able to manufacture 24.6 kilos during the preceding year, but it would then suddenly produce 159 kilos with the seized chemicals.”
. Theoretical yield calculations are clearly permissible; it is the use of a
maximum
theoretical estimate that is problematic.
See, e.g., United States v. Williams,
