Sinclair International Shoulder Bump Gage Insert #21, 21 Degree, 220 Swift

The Sinclair International Shoulder Bump Gage Insert #21, cut at a 21-degree shoulder angle for 220 Swift, lets precision handloaders measure exactly how much shoulder they are bumping back during full-length sizing. Bumping the shoulder too far shortens headspace and can lead to case stretching and shorter brass life, while not bumping enough risks a chamber that will not close smoothly. This insert works with Sinclair’s comparator body to give a repeatable, caliber-correct shoulder measurement before and after sizing, so you dial in the 0.001 to 0.002-inch bump precision bench rest and long-range shooters rely on.

Key Specifications

• Cut to a 21-degree shoulder angle to match 220 Swift.
• Numbered insert #21 in Sinclair’s shoulder bump gage system.
• Designed for use with a comparator or bump gauge body.

Frequently Asked Questions

What does this insert measure? It measures shoulder position on a case, letting you confirm precisely how much shoulder you bumped back during full-length sizing.

What caliber family is this insert cut for? This insert is cut for 220 Swift, matching that family’s shoulder angle.

Do I need a comparator body to use this insert? Yes, this insert is designed to be used with a Sinclair comparator or bump gauge body.

Buy the Sinclair Shoulder Bump Gage Insert #21

Order yours from Sinclair International in our reloading equipment lineup and dial in your shoulder bump with confidence. Order it from our Lubbock, Texas gun shop for fast, insured shipping.