Pilot Diameter Chart
Copyright 2019, Fred Zeglin, reprinted by permission of the author.



These Charts come from Fred’s book, “Gunsmith Tools, Cutters, & Gauges – A Primer“.
There is so much more in the book, check it out!

Copyright 2019, Fred Zeglin, reprinted by permission of the author.
These Charts come from Fred’s book, “Gunsmith Tools, Cutters, & Gauges – A Primer“.
There is so much more in the book, check it out!
You hear some things on the phone that really make you laugh when you rent tools. They might not be funny to the average tool user but maybe we need to share them to clear up some misunderstandings? One of my favorites is, “That barrel has been in the lathe forever waiting for the reamer.”…
Being in the gun business for almost 40 years now I have become acutely aware if the lack of basics being taught in schools. In particular in Occupational Trades institutions. Before you send me a nasty gram defending your favorite school keep in mind I teach at one of these colleges and have friends at…
By Brady Kirkpatirick Introduction If you’re in the world of firearms, you’ve likely heard the term ‘headspace.’ But what is it, and why is it so vital? My name is Brady Kirkpatrick, the founder of GunMade.com, and I’ve spent years delving into the intricacies of firearms, including the concept of headspace. In the simplest terms,…
4D is proud to announce that we have made an exclusive deal with Tyler Jacobs, Owner of Sherman Wildcat Cartridges. We are now the exclusive source to rent proprietary reamers and headspace gauges for the entire Sherman lineup. While Fred Zeglin was working on the second edition of his Wildcat Cartridges book for Gun Digest…
We have seen a ton of demand for Ackley calibers since the publication of Fred Zeglin’s two new books in 2017. For this reason we have created a category on the 4D web site to separate out all Ackley cartridges making them easier to find. They still appear in the standard caliber listings as well….
Fred Zeglin released two titles in his new series of instructional books for anyone who wants to understand how guns work. Tailored to students of gunsmithing, whether you are a hobbyist or a professional Zeglin bring over 3 decades of gunsmithing and teaching to the table. These books are clear and concise detailing specific subjects. Lee…
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