Sinclair Shoulder Bump Gage Insert #23A 23 Degree .25-270 Caliber

The Sinclair Shoulder Bump Gage Insert #23A is a precision reloading tool built with a 23-degree angle for accurate shoulder measurement on .25-270 caliber cartridge cases. It is machined to fit the Sinclair Shoulder Bump Gage system, giving reloaders a dedicated insert for checking shoulder position on this specific case family.

Because the insert matches the 23-degree shoulder angle of the .25-270, it lets you measure and set shoulder bump consistently, which supports uniform cartridge dimensions, reliable chambering, and longer case life. It is a simple, single-purpose accessory for reloaders who want repeatable shoulder measurements rather than guesswork.

Key Features

Compatibility

Fits the Sinclair Shoulder Bump Gage system and is intended for .25-270 caliber cartridge cases.

How to use

Install the #23A insert into a Sinclair Shoulder Bump Gage, then use it to measure shoulder position on .25-270 caliber cases. The 23-degree angle matches the case shoulder for accurate readings.