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Ar-15/M16 Magazine Feed Lip Gauge - Ar-15 Magazine Lip Gauge
Our editorial team reviews specifications, product data, and field-use information to keep pages accurate.
$64.99
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SKU: 080000744
Overview
This gauge is designed to help verify magazine feed lip spacing on standard .223/5.56mm AR-15/M16 magazines before they are put back into service. Its simple go/no-go design provides a quick check for feed lip gap, making it useful for shooters who want to identify magazines that may need adjustment or removal from use. If the gauge passes through the feed lips, the magazine is out of spec and should be corrected with the appropriate tool or discarded; if it will not pass, the gap is too narrow. It is a practical bench tool for maintaining magazine function, but it is limited to standard magazines only and does not address other possible causes of feeding issues.
Why Hunters Choose the Brownells
Convenient Go/no-go
Gauge for checking magazine feed
Helps Identify
Magazines that may need adjustment
Simple Slip-over
Design makes inspection quick and
Machined From
Heat-treated 4140 chrome-moly steel for
Sized Standard
.223/5.56mm magazines only
Key Features
- Convenient Go/No-Go gauge for checking AR-15/M16 magazine feed lip gap.
- Helps verify proper feed lip specs for reliable ammunition feeding.
- Designed to identify magazines with feed lip gaps that are too wide or too narrow.
- Use on standard .223/5.56mm magazines only.
- Go gauge measures .454 inches; No-Go gauge measures .476 inches.
- Machined from 4140 chrome-moly steel and heat treated for dimensional stability.
Best Used For
- Armorer or gunsmith checking standard .223/5.56mm magazines for feed lip spec
- Range user diagnosing suspect magazines before relying on them for training
- Shop workflow needing a quick Go/No-Go check for feed lip gap
- Owners of standard AR-15/M16 magazines wanting to identify out-of-spec feed lips
Specifications
| Compatibility | Standard .223/5.56mm magazines only |
|---|---|
| Go Gauge | 0.454" |
| Hardness | Rc 52-60 |
| Material | 4140 chrome-moly heat treated steel, in-the-white |
| No Go Gauge | 0.476" |
| Purpose | Check correct feed lip gap |
| Tool Type | Go/No-Go gauge |
Pros
- Convenient go/no-go gauge for checking magazine feed lip gap
- Helps identify magazines that may need adjustment or removal from service
- Simple slip-over design makes inspection quick and straightforward
- Machined from heat-treated 4140 chrome-moly steel for dimensional stability
- Sized for standard .223/5.56mm magazines only
Considerations & Trade-offs
- This is a diagnostic gauge, so it does not correct feed lip issues on its own; a separate feed lip tool is needed if the magazine is out of spec.
- It is limited to standard .223/5.56mm magazines only, so it is not a universal check for other magazine types or calibers.
- The gauge provides a pass/fail check for feed lip gap, but it does not evaluate other possible causes of feeding problems.
- Magazines that fail the check may need to be discarded or adjusted, which adds an extra decision step before the magazine can be put back into service.
Suggested Comparisons
- AR-15 magazine maintenance tools
- Magazine repair and adjustment tools
- AR-15 / M16 magazine accessories
Suggested Accessories
- Magazine cleaning brush
- Magazine loader
- Magazine maintenance tool
- Range bag
Frequently Asked Questions
What does this magazine feed lip gauge check?
It is a Go/No-Go gauge for checking the feed lip gap on standard .223/5.56mm AR-15/M16 magazines.
How is the gauge used?
Slip it over the back of the magazine and lightly press it between the feed lips. If it passes through, the magazine is out of spec; if it will not pass, the gap is too narrow.
What are the Go and No-Go dimensions?
The listed specs are Go: .454" and No-Go: .476".
What should I do if the gauge passes through the feed lips?
The product description says to either discard that magazine or use the Brownells Magazine Feed Lip Tool, sold separately, to bring it back into spec.
What magazines is this gauge intended for?
It is for standard .223/5.56mm magazines only.