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BRN AR-15/M16 Colt 5.56x45 NATO Headspace Gauge 1.4736"

BROWNELLS - BRN AR-15/M16 Colt 5.56x45 NATO Headspace Gauge 1.4736"

9 Reviews

BRN AR-15/M16 Colt 5.56x45 NATO Headspace Gauge 1.4736"

Brownells #

319418033

MFR #

COLT 5.56MM H'SPACE GAUGE FIEL

UPC

757253992421

$46.45

Purchase Limit

Out of Stock

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International purchase information

Specifications

Cartridge:

5.56x45 NATO

Headspace Gauge Type:

Field

Color:

Silver

Quantity:

Material:

Steel

Restriction

Gun Tool Restriction:

Yes

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Can we ship this to you? (US only)

How To Buy Guns Online

International purchase information

What is the BROWNELLS - BRN AR-15/M16 Colt 5.56x45 NATO Headspace Gauge 1.4736"?

COLT FIELD 5.56X45MM HEADSPACE GAUGE

Made to the Colt factory's special dimensions for M16/AR-15 rifles. It measures the maximum factory acceptable headspace; an essential check on guns that have seen extensive service or have been rebarreled.

Headspace measurement: 1.4736 Max

SPECIFICATIONS:

Hardened Ground Steel
Length: 1.65"
Diameter: 0.3655"

See all of our AR15s and AR15 parts here.

Gun Tool Restriction
Gun Tools have restricted shipping to CA.

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5.56MM MAXIMUM HEADSPACE GAUGE REVIEWS

4.8

9 Reviews

5 Stars

89%

4 Stars

3 Stars

11%

2 Stars

1 Stars

Reviews Summary

Overall, the Forster 5.56MM Maximum Headspace Gauge receives significant praise for its quality and functionality. Many users find it essential for ensuring safety in their AR builds. Some concerns arise regarding the lack of a relief groove for ejectors, which may require modifications. Despite minor drawbacks, the gauge is seen as a worthwhile investment for AR-15 enthusiasts.

What Reviewers Are Saying

Product Quality

65%

Reviewers are impressed with the build quality of the Forster headspace gauge, noting it is well made and reliable for verifying safety in AR builds. Many express confidence in Forster's reputation.

Functionality and Usefulness

70%

Multiple reviews highlight the gauge's effectiveness in checking headspace, particularly for AR-15 platforms. Users appreciate its role in confirming safety and mil-spec compliance during rifle assembly.

Modifications Required

25%

A few reviewers mention the necessity for modifications, specifically referencing the lack of a relief groove for the plunger ejector. This raises concerns about usability without further adjustments.

Safety Assurance

60%

Several users emphasize the importance of using the gauge to ensure their rifles are safe to fire. The investment is viewed as minimal when considering the potential risks of unsafe headspace.

Price-Value Ratio

50%

Many customers find the price of the gauge reasonable for the peace of mind it provides. They consider it a small cost relative to ensuring firearm safety.

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5.56 field gauge

I bought this along with a set of go/no go gauges....just to have all 3. I just feel better knowing that if I mix and match bolts to barrels between my set ups that they'll be safe....and function properly.

Would you recommend this? Yes, I would recommend to a friend

by GARY HOLDORF on May 01, 2026

Verified Purchase

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The only one I need

I just need to know it’s good to go right now. I know of no one that checks headspace daily.

by WILLIAM DENNIS on December 27, 2025

Verified Purchase

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Perfect For What I Needed!

This was perfect for what I needed. I just assembled an AR from an existing built lower I had, a new upper, and a new BCG I had purchased separately. Being the BCG didn't come with the upper, I wanted to make sure everything was within safe tolerances, and this fit the bill.

by John Battersby on September 06, 2023

Verified Purchase

Was this review helpful? 1

ATTENTION COLT RE-BARREL DIY

Save yourself the time researching why your no go gauge goes in a brand new colt barrel. GET THIS for the MAXIMUM headspace NO GO gauge for COLT barrels. Colt barrels are DIFFERENT than all others and all other no go gauges aren't correct.

5.56 NATO Max H.S. gauge

This gauge is made by Forster which is great because I love their stuff. Very well made and marked perfectly.

View All 9 Reviews

Customer Questions

0 Questions

BROWNELLS - BRN AR-15/M16 Colt 5.56x45 NATO Headspace Gauge 1.4736"

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5.56MM MAXIMUM HEADSPACE GAUGE REVIEWS

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