Wilson Expanding Mandrel

(10 customer reviews)



To be used with the NEW Wilson Expanding Mandrel Sizing Die. Designed to be used on NEW brass cases to prepare the case for the seating opeation. 

Over the past few years we have seen a greater need to run new brass cases over and expanding mandrel to properly prepare them for their first firing.  New brass cases are often damaged when shipped in bulk, this die will give you a consistant neck diameter on your cases.  With correct neck tension you can expect a more consistant seating depth and shot!

Please select size below.

Additional mandrels sold separately

    • Interchangeable Mandrels depending on caliber
    • Expands neck to slightly under bullet diameter 
    • Stainless Parts for a Long Lasting Finish
  • Durable and Accurate



Additional information

Weight N/A
Dimensions N/A

10 reviews for Wilson Expanding Mandrel

  1. Jeff Mertens (verified owner)

    Perfect machining. No burrs and perfect sizing. Service and products offered by Kansas Arms Supply are top notch

  2. marlon elmore (verified owner)

    Very well made and should last a very long time.
    Checked dimensions and all were accurate with mi micrometer.
    Will buy more.

  3. Gregory Webster (verified owner)

    Quality of machine work is excellent, calipers indicate each mandrel is exactly the diameter/caliber it should be

  4. Anonymous (verified owner)

  5. Jeff Mitchel (verified owner)

    I was looking for expander mandrels for setting neck tension, and these are 1. perfect and 2. in stock. Machining is perfect as you’d expect from Wilson and KAS actually had them in stock and got them to me in a timely manner.

  6. Frederick Nordi (verified owner)

    Excellent Service

  7. Hossein (verified owner)

    Great for neck sizing new brass!

  8. MBranden F. (verified owner)

    Best shopping experience in an awful long time. Excellent service, immediate fulfillment. Buy with confidence. Oh, and the mandrel and die are fantastic.

  9. Anthony Camp (verified owner)

  10. Corey S. (verified owner)

    Works as it should, I like being able to swap them out easily when jumping between calibers

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