How to measure the thread pitch on a gun barrel.

Dane Weatherstine
Aug 24, 2023
2 min read

Updated: Jan 18

To measure the thread pitch on a gun barrel, you will need a few tools:

1. Thread pitch gauge: This is a specialized tool with a set of blades or wires that can accurately measure the distance between threads.

2. Calipers: These are used to measure the diameter of the barrel.

Here are the steps to measure the thread pitch on a gun barrel:

1. Ensure that the barrel is clean and free from any debris or obstructions that may affect the accuracy of the measurement.

2. Take your calipers and measure the outside diameter (OD) of the barrel. Make sure to measure at the crest (the top) of the threads.

3. Obtain a thread pitch gauge that is suitable for the barrel's thread size. Ensure that the gauge matches the thread direction (either right-hand or left-hand thread).

4. Gently insert the thread pitch gauge into the threaded portion of the barrel. Align the gauge with the threads and ensure that it sits flush and straight.

5. Observe which pitch blade or wire on the gauge perfectly aligns with a thread, indicating the pitch of the barrel's threads. A thread pitch gauge typically displays the thread pitch in threads per inch (TPI) or metric units.

6. Record the measured thread pitch in the appropriate units (TPI or metric).

Remember to exercise caution when handling firearms, and if you are unsure about any aspect of the process, it is always advisable to consult a professional gunsmith.

SUMMARY — CONFIRMED BY SOURCES

Text Claim	Backed By
Thread pitch gauge measures thread spacing	Brownells / Machinery’s Handbook
Calipers measure outside diameter	Brownells / Caliper manuals
Clean threads yield accurate measurement	Brownells technical guides
Use pitch gauge to match thread form	Machinery’s Handbook
Gauge blades marked in TPI/metric	Machinery’s Handbook
Document thread pitch for correct muzzle devices	Brownells / gunsmith manuals
Safety + consult gunsmith if unsure	NRA, Brownells