Working with old and interesting guns likely requires precise custom internal measurements. Here’s why and how to slug your barrel.

by Paul Mazan

Many old guns have bores that do not conform to what today are “standardized” dimensions. To get them to shoot accurately, you must measure the bore and match a bullet to it. Here is how to do it.

Barrel Slugging

To achieve any degree of accuracy, you cannot simply depend on commercially loaded ammunition to load a bullet that will fit the bore of your rifle or that the bore matches the stated caliber. You will want to be sure to slug the bore and find a bullet that is at least bore diameter. Unlike modern guns, there is much more variation in the actual barrel diameters in old guns of the same model and caliber. These guns were built in the early part of the Industrial Revolution and tolerances, especially between manufactures, was not as closely held as they are today.

The chart published with my article provides examples of…

Read more in the May 2022 issue.

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