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The U.S. Army's Preventive Maintenance Magazine
The U.S. Army's Preventive Maintenance Magazine
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PS How-To Videos
70th Anniversary Blog
MK19 Grenade Machine Gun: Army Continues to Perform Semiannual DTI
| Oct. 17, 2023
The Army will continue to perform the MK19 grenade machine gun semi-annual bolt and backplate detailed technical inspection (DTI). Read on for the full story…...
M240B Machine Gun: Don’t Forget the Scraper Tool
| Sept. 13, 2023
Cleaning the M240B machine gun’s gas system is an important part of maintaining your weapon. Clean the whole gas system to keep your weapon firing. Keep reading to get the whole story…...
M240 Machine Gun: Need a BFA Discriminator?
| Aug. 10, 2023
The discriminator will be added to the M240 machine gun additional authorization list (AAL) according to TACOM. Here's how to get one...
MK19 Grenade Machine Gun: Upgraded Rear Sight Assembly
| June 13, 2023
The MK19 grenade machine gun has an updated rear sight assembly. Contact the MWO coordinator if your unit needs to have the MWO installed. Read on to learn more…...
M240 Machine Gun: Dry Firing Can Crack the Receiver
| June 9, 2023
When handling the M240, it’s important to never dry fire the weapon. When the locking bar strikes the guide rails, the force can cause it to crack. This will take your M240 out of the fight. Keep reading to find out more…...
M2A1 Machine Gun: Enhance Training with Visual User Guide
| March 6, 2023
The visual user guide (VUG) is a great resource to train soldiers on the M2A1 machine gun. It was issued when the weapon was fielded but if you need a copy, we have the link. There's also a headspace and timing VUG for the...
M240B Machine Gun: Properly Clean the Gas System to Avoid Malfunction
| Feb. 14, 2023
If the M240 machine gun isn’t cleaned properly, to include using the proper special tools, then the weapon can malfunction. Keep reading to see how to properly clean the gas port system...
Small Arms Year-in-Review: New and Updated NSNs Captured in 2022
| Jan. 13, 2023
Updated or new NSNs are a challenge to keep up with. Here’s a list that PS captured in 2022 for small arms. Get them here...
MK19 Grenade Machine Gun: Rear Sight Parts
| Dec. 21, 2022
If you need an MK19 machine gun rear sight, there’s a new NSN. Keep reading to get the info…...
M2A1 Machine Gun: Enroll Wear Limit Gage in TMDE
| Dec. 21, 2022
It is important to have your wear limit gages enrolled in the TMDE program. Here's why...
M2A1 Machine Gun: Turn in Barrel Carrying Handle?
| Dec. 8, 2022
If your unit has an unserviceable M2A1 barrel, don’t turn in the carrying handle if it’s still serviceable. Here's why...
Small Arms: Does Your Weapon Need LAW Instead of CLP?
| Dec. 7, 2022
When operating your weapon in extremely cold weather environments, CLP may not be the right lubricant. Keep reading to find out how to determine if you need to use lubricating oil arctic weapons (LAW)…...
M240H Machine Gun: Need an Egress Kit?
| Oct. 4, 2022
If you need an M240H emergency egress kit or one of its components, keep reading...
Weapon Installed on CROWS? Lock on Lowest Elevation for Travel!
| Sept. 29, 2022
When operating a vehicle with CROWS installed keep the CROWS locked at the lowest elevation unless in use. Keep reading for the facts...
MK19 Machine Gun: Spring Measurement No Longer Needed
| Aug. 30, 2022
Mechanics, continue to inspect the condition of the MK19 shuttle and sear springs but disregard any references to measuring the springs. Keep reading for the full story...
M249 Machine Gun: Ejection Port Covers Working Loose
| June 27, 2022
After operators fire their M249 machine guns, they should take a minute and check the ejection port cover pin to see if it’s coming loose. If unchecked, the pin will work its way out. Read on to learn what to do if this...
M242 Automatic Gun: Safety Handle Trouble? Read MA 22-032!
| April 25, 2022
Operators and maintainers, the M242 automatic gun safety pawl, NSN 3040-01-167-8326, may not be to standard because hundreds were made using outdated drawings and specifications. Here's how to deal with this issue...
M249 Machine Gun: 3D-Printed Front Sight Post Adjustment Tool
| April 21, 2022
TACOM has adopted 3D printing, an advanced manufacturing technique, to produce parts. One of the first parts produced using this method is the M249 machine gun front sight post adjustment tool...
M2A1 Machine Gun: Confirm Your Weapon Was Gaged Prior to Firing
| April 13, 2022
Gunners, one of the biggest improvements of the M2A1 machine gun over the M2 machine gun is that you no longer need to headspace and time your weapon before firing. But you can’t forget about headspace and timing (HS&T)...
M2/M2A1 Machine Guns: Ammo for Training on Short Range
| March 21, 2022
Don’t let limited space to fire the M2/M2A1 machine gun stop your unit from training. With an impact area of only 700 meters, short-range training ammunition (SRTA) is an available solution. You can order SRTA under DODICs...
M240/M249 Machine Gun: Store With the Bolt Forward
| Feb. 2, 2022
Some M240 and M249 machine guns are being stored with the bolts locked to the rear...
M249 Machine Gun: Is Your Buttstock Coming Loose?
| Dec. 1, 2021
Dear Editor, we work at TACOM FMX and have noticed the adjustable buttstock on M249 machine guns is coming loose from the back plate. This can be fixed by tightening the buttstock. Here's how...
MK 19 Grenade Machine Gun: Always Lock the Sear in Place
| Nov. 29, 2021
Dear Editor, when Soldiers disassemble the MK 19 grenade machine gun, they should make sure after removing the sear plate assembly from the receiver that their priority is putting the sear safety lock on. Read on to discover...
M2/M2A1 Machine Guns: Are There Mandatory Replacement Parts?
| Nov. 3, 2021
There was an article on Page 41 of PS 767 (Oct 16) that said the M2A1 machine gun’s mandatory replacement parts had been eliminated. Has there been any change to this statement? The M2A1’s -23&P TM still shows these parts...
M249 Machine Gun: Don’t Clog the Gas Port
| Sept. 22, 2021
Dear Editor, in our weapons shop, we’ve noticed some Soldiers have cleaned their M249 gas piston assembly and left cleaning patches or other cleaning material behind inside the weapon. Here's what we recommend doing to avoid...
M249 Machine Gun: Won't Fire? Check Piston Pin
| Aug. 12, 2021
This article initially appeared in PS 758 (May 16), p. 42. Dear Editor, Recently I was trying to repair an M249 that wouldn’t fire. It would chamber rounds and extract them with no problem...
UH-60M: How to Get an M240 Ammo Can
| July 20, 2021
Dear Half-Mast, I’m trying to find information on the M240 ammo can used in the UH-60M Black Hawk. What’s the ammo can’s NSN and which TM should I use to learn more about it? SFC V.C...
M249 Machine Gun: Dimple Usually Not a Problem
| July 14, 2021
This article initially appeared in PS 788 (Jul 18), p. 42. When M885A1 rounds are fired through an M249 machine gun, a small dimple is often created in the feed throat of the barrel...
MK 19 Grenade Machine Gun: Make Sure to Lace the Bolt Correctly
| May 10, 2021
Dear Editor, during several MK 19 grenade machine gun services, we’ve noticed what could be considered incorrect wire lacing on the bolt. Nuts are laced together to reduce any and all movement or as much movement as possible...
M2A1 Machine Gun: Barrel Extension Excessive Wear and Timing Adjustment
| March 18, 2021
Dear Editor, there are reports that some M2A1 barrel extensions have excessive wear and damage. This damage is occurring because the M2A1 timing adjustment isn’t being performed during...
M2A1 Machine Gun: When Is the Flat Spring Needed?
| Nov. 12, 2020
Don’t know if your M2A1 machine gun requires the flat spring, PN 5140428? Here’s some help. The flat spring, NSN 1005-00-514-0428, PN 5140428, on the bottom of the M2A1 machine gun’s receiver...
M2 and M2A1 Machine Guns: Not All Parts Are Interchangeable
| July 27, 2020
Although the M2 and M2A1 .50-cal machine guns look alike, they aren’t. So when units swap parts from one model to the other, they risk damaging the weapon and injuring Soldiers. If your unit has both machine guns, keep the...
M2A1 Machine Gun: How to Install the Barrel Correctly
| May 14, 2020
Here at PS, we like to remind Soldiers and other readers of the importance of doing things right. History has shown that some Soldiers install the M2A1 barrel incorrectly. As a result, the barrel’s alignment pin shears off...
M48 Machine Gun: Replacing Missing Solenoid Parts
| April 7, 2020
Dear Editor, When adjusting the timing on the solenoid of an M48 machine gun mounted on the M1117 ASV, sometimes the locking screw and washer get lost. Our search in both the M48 and M1117 TMs showed no replacements for the...
M240 Machine Gun: Not All Buffers Are the Same
| March 30, 2020
The story on the top of Page 39 in PS 801 (Aug 19) pointed out that units are seeing cracks in the M240 gun’s channels where the buffer assembly and buttstock slide in. Cracks mean the M240 must be replaced...
M240 Machine Gun: Front Mounting Bushing Can Spin
| March 20, 2020
Soldiers, we have an update on the M240 machine gun’s front mounting bushing. If it spins, that doesn’t deadline the weapon. On Page 41 of PS 788 (Jul 18), we said if there was any movement of the front mounting bushing, the...
M2A1 Machine Gun: Protect the Mounting Pin and CROWS Elevation Servo
| March 9, 2020
Dear Editor, Which is stronger: the CROWS elevation servo motor or the M2A1 machine gun mounting pin? Trick question! The answer is, neither. After the machine gun is removed from the mount, make sure to push the pin back in...
M249 and M240 Machine Guns: Tag the Barrels
| Jan. 24, 2020
Soldiers, your M240 and M249 machine guns have two or more barrels. As you probably know, the barrel has to be gaged to the weapon. So make sure they’re marked with the weapon serial number. Otherwise, confusion can occur...
M2A1 Machine Gun: Feed Tray Pin PM
| Jan. 13, 2020
Some Soldiers aren’t using the right pin on their M2A1 machine gun’s feed tray and that’s an accident waiting to happen...
M2A1 Machine Gun: Marking the Gage
| Jan. 13, 2020
Marking the M2A1 gage with a serial number is required. But care must be taken not to mark it in a critical area. Instead, Soldiers should attach a dog tag marked with the serial number...
M2A1 Machine Gun: Install the M19 BFA the Right Way
| Jan. 7, 2020
Some Soldiers out there are just doing it wrong! They're trying to install the M19 blank firing attachment (BFA) over the flash suppressor of the M2A1 machine gun. Spoiler alert: it won't fit!...
MK19: Property Book Serial Number Confusion Cleared
| Dec. 19, 2019
Dear Editor, some units with MK19 grenade machine guns (Mods 3 and 4) have incorrect serial numbers listed on the property book. That's because the weapon is etched/engraved with both a serial number and the month/year of...
M240 Machine Gun: Clean Your Weapon After Firing It
| Dec. 17, 2019
Soldiers, it’s important to clean your weapon every time you fire it! A maintenance facility reported receiving M240 machine guns with barrels stuck in the receiver. The cause of the problem was the weapons didn’t get cleaned...
M230 Automatic Gun: Target These Tips
| Dec. 9, 2019
Target these tips to keep your M230 automatic gun on target, particularly in a desert environment:...
M240L Machine Gun: BFA Correction
| Nov. 18, 2019
On Page 31 of PS 797 (Apr 19), we said to use the M24 BFA, NSN 1005-01-480-0289, with the M240L machine gun. But with the application of MWO 9-1005-313-23-4, the M240L changed from the standard barrel to a short barrel...
M249: Carrying Handle Collar Inspection Criteria Clarification
| Oct. 30, 2019
Soldiers,We need to clarify what was stated in our M249 barrel collar story on Page 39 of PS 802 (click on image below to access copy of the article). Yes, it’s true the barrel is NMC if there is any movement of the barrel...
M249 Machine Gun: Scraper NSN Changes
| Oct. 22, 2019
When your M249 machine gun’s scraper tool wears out, don’t use NSN 1005-01-131-1914 to order a new one. Here's the new NSN...
M2/M2A1 Machine Gun: How To Stop M2/M2A1 Damage
| Oct. 16, 2019
Too many M2s and M2A1s are being damaged because Soldiers aren’t thoroughly trained on how to fire and maintain them. Here’s What units need to do to stop that damage...
M2A1 Machine Gun: How Much Bolt Erosion is Too Much?
| Sept. 30, 2019
Dear Half-Mast, WP 0018 00-3 in the M2A1 machine gun’s TM 9-1005-347-23&P (Jul 11) says to inspect the bolt face for pits and/or eroded areas up to .062 inches long or wide, .031 inches deep in scattered or random patterns,...
MK19 Machine Gun: Stop Slamming and Jamming
| Sept. 3, 2019
Even on a heavy-duty weapon like the MK 19 machine gun, slamming and jamming can cause heavy-duty damage. Keep reading to learn more...
M2/M2A1 Machine Gun: Load Like This
| Aug. 1, 2019
Loading your M2/M2A1 machine gun incorrectly can do a number on its bolt...