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Oval Egg Sinkers to Slug Your Barrel!
J. Marshall Stanton on 2012-07-07

In slugging firearm barrels to determine internal barrel dimensions, common ordinary oval egg sinkers do a wonderful job. They are ideally suited to the task, they are pure lead, so they are butter-soft and go down a bore easily, secondly, their egg shape facilitates starting them down the bore, and also, there’s a limited amount of bearing surface of the sinker that is actually full groove diameter. Lastly, the fact that they have the longitudinal hole running the length of the sinker gives compressed lead a place to migrate to when it goes through a constriction, and thereby gives a much more accurate and true dimension of the internal measurements of the barrel since a solid lead ball would have a residual “spring-back” memory, which can actually give up to .0015” oversize readings when measured, simply because it is a solid ball, unlike the oval egg sinker with the hole running though it.

Oval egg sinkers come in a variety of sizes, and for the purposes of slugging firearm barrels, however, no one sinker is absolutely suited to doing all jobs, that’s why we have different sizes. For instance a #8 oval egg sinker is about ideal for .40 caliber, .41 caliber and .44 caliber applications. However, when used in .45 caliber barrels, both handgun and rifle, this #8 oval egg sinker is too small to totally fit to the bottom of the grooves in a .45 caliber barrel.

The nice thing about these little jewels, is if you squeeze them endways in either a bench vise or a large pair of pliers, the middle section of the sinker grows in diameter as it is reduced in length. It works like a charm, and can be used in many applications where a given size egg sinker is just a little too small, but the next size up would be WAY too big!

The nice thing is, that you can basically tailor them to fit your application with just a little finesse on how much they are squeezed.