A 303 beer can bottom end is a can-end size designation, but the code alone does not confirm that an end will fit a particular can body or seaming setup. Before requesting a quote, compare the end drawing with the can maker’s body dimensions, the seamer and tooling, and the required double-seam specifications. If the designation follows the traditional can-size convention, “303” represents 3 3/16 inches, or approximately 80.96 mm, as a nominal size reference—not a substitute for a controlled technical drawing. Use this guide to define the information your supplier needs to assess compatibility and prepare a reliable quotation.
This guide is intended for beverage can manufacturers, breweries, contract packers, packaging purchasers, and engineering teams sourcing 303 beer can bottom ends. It is especially useful when qualifying a new supplier, changing a can component, or investigating a mismatch between ends and existing equipment. Buyers should involve both procurement and production personnel, since commercial availability and line compatibility are separate questions. The final specification should be approved by the parties responsible for the can body and seaming process.
Can-end size codes are used as shorthand, but their interpretation and the dimensions associated with them should be confirmed with the supplier. Under a traditional fractional-inch convention, the first digit indicates whole inches and the remaining digits indicate sixteenths; on that basis, 303 corresponds to 3 3/16 inches. Since 1 inch equals 25.4 mm, this nominal reference converts to approximately 80.96 mm. The conversion explains the code; it does not establish the finished end’s outside diameter, fit, or seam dimensions.
Do not approve a purchase based on “303” alone. Suppliers may use product-specific drawings, internal codes, or dimensional definitions, and a size label may not capture every feature required for your application. Ask for a current drawing and confirm which diameter the drawing identifies, such as the curl or another specified measurement. Compare that drawing with the can-body specification and seamer tooling before placing a production order.
Ask the supplier to identify the proposed substrate, material thickness, and coating or lacquer system. The appropriate construction depends on the product, contact requirements, forming process, and the buyer’s packaging specification. Request written confirmation of the material and coating details instead of assuming that two ends with the same size code are interchangeable. Any food-contact or regulatory requirements should be stated explicitly and supported by documentation applicable to the intended market.
For a bottom end, confirm the panel profile, curl, countersink, and other features shown on the technical drawing. Also state whether the component is a plain bottom end or has a special design requirement, and clarify whether it must match a particular end family. Opening features are generally associated with can tops, but buyers should still specify whether the top and bottom ends need to match in material, appearance, or coating. Wanhua can review the information supplied and discuss the available product options against the buyer’s documented requirements.
A useful inquiry includes the nominal size code, a dimensioned drawing, the can-body dimensions, material and coating requirements, and the intended application. Provide the seamer make and model, relevant chuck and roll information, and the target seam requirements defined by your equipment or packaging standard. If you are evaluating a replacement part, include the existing end’s part number and a sample or drawing where available. These details help distinguish a genuinely compatible option from one that merely shares a size label.
Start with the can-body drawing and identify the body flange and other interface dimensions used in the seam. Compare these with the end curl and profile on the proposed end drawing. A dimensional discrepancy at the interface can affect feeding, engagement, or the resulting seam, so have the can-body and end suppliers review the same revision-controlled documents. Do not rely on visual comparison or a size code as the sole acceptance method.
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Confirm that the end profile is suitable for the seamer, chuck, and seaming rolls used on your line. Seaming settings and tooling are machine- and component-dependent, so a setting that works with one combination should not be assumed to work with another. Ask the supplier and equipment provider to identify any setup changes or validation steps required before production. Record the approved combination of can body, end, tooling, and machine settings for future reference.
Where practical, conduct a controlled trial using the intended can body and production equipment before approving routine supply. Inspect the resulting double seam using the measurement and evaluation methods specified by your quality system or equipment provider. Review dimensional results and visual condition together, and resolve any deviations with the responsible technical teams before release. A sample trial is a validation step, not a guarantee that every line or product will perform identically.
Evaluate each candidate against four areas: documented dimensions, material and coating suitability, line compatibility, and supply terms. First, confirm that the drawing matches the interface and equipment requirements. Next, check that the proposed construction meets your product and market requirements, with supporting documentation where needed. Finally, establish how samples, production approval, changes, and repeat orders will be managed.
| Selection Area | What to Confirm | Why It Matters |
|---|---|---|
| Dimensions | Drawing revision, end profile, curl, and interface dimensions | Helps establish fit with the can body and tooling |
| Construction | Material, thickness, coating, and finish | Connects the component to product and packaging requirements |
| Production use | Seamer details, trial plan, and inspection criteria | Supports a controlled compatibility assessment |
| Supply | MOQ, lead time, packaging, and change communication | Allows buyers to plan purchasing and production |
Pricing for a 303 beer can bottom end can depend on the specified material, coating, order volume, packaging, and any customization or qualification work. Minimum order quantities and lead times are supplier- and order-specific, so request current figures rather than relying on an assumed industry standard. For a comparable quotation, send the same drawing revision and annual or order-volume estimate to each supplier. Ask whether sample charges, tooling requirements, freight, and packaging are included or quoted separately.
Include the required delivery location and timing in your inquiry, and ask the supplier to state the basis of its lead-time estimate. If a specification is still under review, separate sample evaluation from the expected production order so that both steps can be planned. Confirm how changes to material, drawing, or packaging will be communicated and approved. These questions help buyers compare the full supply arrangement rather than unit price alone.
Before selecting a supplier, check whether it can provide a clear drawing, answer dimensional questions, and explain what information is needed to assess your seaming application. Request the material and coating details relevant to your market, along with any applicable product documentation. Establish whether the supplier can support sample evaluation and how technical issues will be handled during qualification. Also confirm order terms, packaging, delivery assumptions, and procedures for communicating specification changes.
When contacting Wanhua, share your 303 requirement together with the can-body drawing, seamer information, desired material and coating, destination market, and estimated order quantity. This gives our team a practical basis for discussing specification fit, available options, samples, and quotation details. If you have an existing end, include its drawing or part reference so the requested replacement can be reviewed against the current design. Final compatibility should be confirmed through document review and, where needed, a production trial on the intended line.
A 303 designation can help identify a nominal size, but it does not by itself prove that a beer can bottom end will form an acceptable seam on your equipment. Confirm the complete drawing, material and coating requirements, can-body interface, and seamer setup before approving supply. Treat the 3 3/16-inch or 80.96 mm conversion as a size-code reference only, and verify the actual dimensions on the supplier’s controlled drawing. For a clear next step, send Wanhua your technical documents and sourcing requirements to begin a specification review and request a quotation.
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