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GENERATION II EXPANDER DIES Reviews & Ratings

SINCLAIR INTERNATIONAL GENERATION II EXPANDER DIES

Large caliber die body for use with our large caliber mandrels.

Expander dies are an essential companion to neck turning tools. They enable the expander mandrel to produce the correct fir of the case neck on the neck-turning mandrel which is vital for accurate, easy neck turning. Expander dies and mandrels can also “iron out” dinged case necks, set consistent case neck size for uniform bullet tension or to “neck up” cases one caliber at time for wildcat cartridges.

Our Generation II Expander Dies completely capture the mandrel within the die so the mandrel cannot pull out. An O-ring in the die allows the mandrel to float a bit and find its own center within the case neck. All three Generation II dies are precision machined from stainless steel and the 7/8”-14 dies include the Sinclair Stainless Steel Split Lock Ring.

All expander mandrels for Sinclair Expander Bodies are sold separately: Find Mandrels here.

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5 Stars

91%

4 Stars

3 Stars

2 Stars

1 Stars

Reviews Summary

Users highly appreciate the GENERATION II EXPANDER DIES for its high quality, precision, and effective neck tension control in brass resizing. Many report improved accuracy and maintain that it’s well worth the investment despite some concerns about price and occasional issues with smaller cases. Overall, it's regarded as a must-have tool for reloading enthusiasts.

What Reviewers Are Saying

Product Quality

75%

Many reviews highlight the exceptional build quality of the expander die, noting that it features robust construction and precise machining. Users express satisfaction with its effectiveness in providing accurate neck sizing and improving case neck tension, consistent with the high standards expected from Sinclair products.

Performance

70%

Reviewers frequently mention the positive impact on accuracy when using the expander die, with many reporting improvements in their shooting performance and reduced runout. The die's ability to control neck tension while resizing brass cases is widely regarded as a significant benefit, thus enhancing overall precision.

Ease of Use

60%

Customers find the expander die user-friendly, appreciating features like the O-ring that allows for some float, which aids in centering the brass during resizing. Many users share that it integrates well with other equipment and is easy to set up, making the reloading process smoother and more efficient.

Value for Money

50%

While a significant number of reviewers recognize the great quality and performance of the expander die, there are sentiments about its pricing. Some consider it a bit overpriced compared to alternatives, but many justify the cost due to the benefits and quality it delivers, making it a worthwhile investment for serious reloaders.

Compatibility Issues

40%

Several users report minor issues when using the die with smaller cases, cautioning that proper alignment is crucial to avoid damage. While many highlight its versatility across different calibers, detailing usage with both carbide and HSS mandrels, some mention the need for careful handling to achieve desired results.

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Simple solution

I'm not sure why I took so long to switch from expander ball to mandrel to set neck tension. The Sinclair solution is simple, fast and effective. I just ordered my 4th mandrel now.

Would you recommend this? Yes, I would recommend to a friend

by KEVIN NEUMANN on June 16, 2026

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Thanks

Been waiting for some time for these to come back in stock.Love the units. I use them for .223, 6.5 and .308. Nice not to have to change the mandrel and reset each time.

by ARTHUR J BANKS on August 24, 2025

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Die for carbide mandrel

Everything i read about the carbide mandrel being the Mercedes Benz of mandrels is true,no lube required. Use on new brass to set neck tension,remove out of round on spent brass,a must have. Thanks to all at Brownells!

Would you recommend this? Yes, I would recommend to a friend

by CLAY TOMLINSON on January 26, 2025

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Sinclair is always good

Well made good Sinclair quality. At a reasonable price.

Would you recommend this? Yes, I would recommend to a friend

by Shawn Rupp on December 06, 2024

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Great expander

An effective process to control neck runout. It's an extra step, but it is worth it.

by KENNETH MYERS on March 25, 2024

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Always great value

I can count on Sinclair/Brownells

by BLAIN BURGESS on November 01, 2023

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Excellent Mandrel Die

The Sinclair mandrel die is manufactured to high standards and features robust construction. This die works well with the tungsten carbide mandrel for producing accurate neck size

by Ronald Spees on August 20, 2023

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Precision Product.

I am not sure why the standard die set doesn't come with an expander mandrel. I.M.O. The regular expander ball (even in expensive die sets) is not the best way to resize without stretching the brass cases. This is a great product that is precisely manufactured - I am glad that I finally found it!

by PAUL WILLIAMS on August 07, 2023

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Only way to go

Bought one for every caliber I own.Now I get the perfect neck tension on all my shells. Be aware on the small cases you must make sure that they line up with the mandral or you will damage some of your small cases.like your 223s. All bigger case are a breeze.takes a little longer but well worth your time.

by Larry on July 14, 2023

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expander die

haven't used it yet but looks like quality made .