I know it seems like I’m pimping the heck out of it, but the 82nd Abn Div Small Arms Master Gunner Facebook page continues to share accurate and relevant content on the use of the M4/M16. Take for instance the info they recently shared on the USGI 30 rd Magazine Go/NoGo Gauge.
The Small Arms Master Gunner writes:
According to Maintenance Information Message #16-039, the Enhanced Performance Magazine is meant to replace the existing approved magazine (with a Tan follower) in the Army’s inventory as the old magazines become unserviceable. This does not include all the magazines that have black and green followers that are still out there from the M16 that should be turned into DRMO, not issued. But how do we know when our approved magazines are unserviceable?
PS Magazine from March of 2011 gives us the answer. There is a Magazine Go/NoGo gauge available to let you know if the feed lips are out of tolerance, and therefore likely to cause feed issues.
Picture two shows the article discussing its use and the NSN. If you have magazines that do not pass the test with the Go/NoGo gauge, they are supposed to be replaced as per PSMagazine.
The NSN for this gauge is 5120-01-574-0036. If you cannot get it through supply channels, Brownell’s also has it for sale where it is known as the AR-15/M16 MAGAZINE FEED LIP GAUGE. Picture three shows it on their website. Brownell’s also has GSA pricing, so it is possible for GPC purchase of this item.
There should at least be one of these per Arms room. Ideally, there should be one of these per Platoon, as then soldiers can diagnose their magazines as a part of their weekly PMCS. And as their magazines fail to meet the spec of the gauge, they can be turned in, and replacements ordered. This is a way around the supply NCO issuing out bad magazines. Any magazines that are turned into the supply NCO that are bad need to be marked in some way so as to leave no doubt in that supply NCO’s mind that these magazines are broken and should not be reissued.
So to sum up: Any magazine that does not look like the magazine on the left in picture 1 or a Magpul Gen3 magazine is a NOGO and should not be used, as they will cause damage to the M4 or M16 with the M855A1 EPR. Existing approved magazines should be checked for spec with the Go/NoGo Gauge regularly, and if they do not meet the spec, they should be turned into the supply sergeant for a new magazine.
I didn’t realize there was even a gauge, let alone what it looked like. These guys went a step further and shared photos to help you understand how it’s used.
Some people had questions from the feed lips tool post as to how much of a difference there was between a go and nogo. I’ve got one of the prototype tools present ton give you an example of its use.
If you look in picture one, you will see the tool on the back side of a tan follower USGI magazine.
As you can see, the nogo side is the top side, if it stops before reaching the nogo side, the feed lips are within tolerance. There is a considerable difference between go and nogo.