Cleaning The MP5SD

    Good evening everyone and thank you for joining us for the 75th edition of TFB’s Silencer Saturday. After a year and a half we have covered a lot of suppressed ground. But we still have a solid supply of topics, review ideas and unique silencer host combinations. As we discussed last week, we will kick the summer off with the review of the YHM Turbo K coming up soon. But for this week, let’s take a brief look at cleaning the MP5SD.

    SILENCER SATURDAY #75: Cleaning The MP5SD

    SILENCER SATURDAY #75: Cleaning The MP5SD

    First, if you are looking for a field strip guide for the MP5, one of TFB’s resident experts, Vlad O., put together a step-by-step pictorial just this week:

    Don’t forget the four rules of gun safety.

    Today’s walkthrough will be specific to the MP5SD and it’s silencer. First, a suppressed MP5 calls for a 500 round cleaning schedule. From the H&K manual:

    H&K MP5 Operators Manual

    At H&K we recommend two types of operator cleaning. Normal cleaning and Major cleaning.

    • Normal cleaning – Performed after each firing or every twelve (12) months.
    • Major cleaning – Often referred to as “detailed cleaning”. Performed on an unsuppressed MP5 after 1,000 rounds (500 for a suppressed MP5) or when the weapon is exposed to or excessively laden with sand, dust, water or other visible contaminants or foreign matter.

    SILENCER SATURDAY #75: Cleaning The MP5SD

    On top of the obvious effects of being suppressed, cleaning the MP5SD focuses on the ported barrel and the silencer attachment area. Take a look at the barrel porting and note why the MP5SD requires additional maintenance over non-integrally suppressed firearms.

    Here’s the ported barrel as installed on a TPMSD from TPM with the SD silencer removed.

    SILENCER SATURDAY #75: Cleaning The MP5SD

    SILENCER SATURDAY #75: Cleaning The MP5SD

    From the H&K MP5 armorers manual, here’s a diagram showing the barrel ports related to the chamber and barrel extension. Check out the 300 round cleaning recommendation.

    The operators manual calls for the use of a barrel cleaning device which can be purchased from several retailers. We’ll get into that specific part and the actual cleaning process below. Check out the “more aggressive cleaning method” if the MP5SD exceeds its recommended cleaning schedule.

    H&K MP5 Operators Manual – MP5SD

    On the MP5SD only, attach the optional Barrel Cleaning Device (H&K ID # 225376) to the end of the sound suppressor body. Push the entire assembly over the end of the barrel all the way down until the cleaning device (similar to a battery terminal cleaning brush used on car batteries) makes contact with the base of the barrel. Rotate the sound suppressor and the cleaning device in a clockwise direction 6-7 complete turns and remove.

    This will clean the exterior of the barrel and the thirty (30) barrel ports that vent the propellent gases (and carbon) into the sound suppressor when the weapon is fired.

    In a weapon with a severe buildup of carbon on the outside surface of the barrel the sound suppressor may be difficult to unscrew or remove from the barrel. This excessive buildup occurs when the barrel cleaning device is not used frequently enough during and/or after firing. The carbon has accumulated to the point where it bonds the sound suppressor to the threads of the barrel.

    At this point a more aggressive cleaning method must be taken. Remove the sound suppressor without using tools. Have one person hold the weapon down while the other unscrews the sound suppressor. For a sound suppressor that is impossible to remove immerse the upper portion of the sound suppressor and barrel in solvent to help loosen the carbon bond. Let the solvent work for one hour. Try again to remove the sound suppressor, with your bare hands only. The use of tools to try and remove the sound suppressor will damage the aluminum housing and destroy the unit. If at this point you can still not unscrew the sound suppressor, contact H&K’s Repair Department for further assistance.

    Once the sound suppressor is unscrewed it may be difficult to slide it off of the barrel over the ring of carbon built up around the gas ports. Work the sound suppressor back and forth along the length of the barrel to break up the ring of carbon so that it can be removed.

    Once the sound suppressor is removed, use a large, flat head screwdriver to scrape away the build up of carbon on the exterior of the barrel only. If possible, cut a dull concave shape into the end of the screwdriver so that it conforms to the outside radius of the barrel to prevent gouging of the barrel’s surface. Keep the screwdriver away from the threads and the front one inch of the barrel, which acts as a bearing surface for the sound suppressor. Remove the carbon by holding the screwdriver on a shallow angle attaching the barrel through the slots in the barrel casing. Do not use too much force. Take care only to remove the carbon build up. Once you have finished with the flathead screwdriver, use the barrel cleaning device as described above to clean off the remaining carbon particles.

    For all H&K Sound Suppressors – Use a nylon bristle toothbrush and rag or swab to remove all fouling from the threads of the sound suppressor. Tap the sound suppressor lightly on a padded surface or blow it out with compressed air to remove any loose fouling from inside the suppressor body. (Do Not immerse the sound suppressor in solvent or insert any rods, brushes or patches into the sound suppressor body!
    Wipe the outside of the sound suppressor off with a clean, oil-free rag. Do not apply oil to the outside of the sound suppressor or it will burn off during firing and obscure the firers view of the target.

    Credit r/MP5 – reddit 

    There’s a sealing ring that is in between the silencer and the barrel extension. I’ve attempted to photograph the ring in place below.


    SILENCER SATURDAY #75: Cleaning The MP5SD

    SILENCER SATURDAY #75: Cleaning The MP5SD

    Also of interesting note is the recommended ammunition that should be run in the MP5SD and the advantages of running standard supersonic 9mm rounds available around the world.

    H&K MP5 Operators Manual – MP5SD

    MP5SD/SD-N with integral suppressor

    The MP5SD was designed to be used exclusively with supersonic ammunition with a muzzle velocity of at least 1,088 feet/ second at sea level. It should not be used with subsonic ammunition with a projectile weight of less than 140 grains! While subsonic ammunition with a projectile weight of less than 140 grains fired in the MP5SD may provide enough recoil energy to cycle the action of the weapon it may not provide sufficient terminal ballistics downrange to incapacitate the target.

    The use of subsonic ammunition in the MP5SD will not result in an appreciable increase in the sound reduction of the weapon (only about 1 dB in fact) . Thus there is little or no reduction in the report of the weapon yet there will be a considerable (16 – 24 %) reduction in the velocity of the projectile and subsequently the terminal effect of that projectile on target.

    The advantage of the MP5SD is that the user can use standard supersonic ammunition, available worldwide, and have an effective sound suppressed weapon without the need for special subsonic ammunition. The disadvantage to the MP5SD is that it should not be used with the subsonic loads with projectile weighing less than 140 grains and it must be used at all times with the sound suppressor attached.

    Attached to the MP5SD is a 12 inch long, sealed, all aluminum sound suppressor that can be removed by the operator for cleaning. This integral sound suppressor surrounds the weapon’s 5.73 inch barrel which has thirty (30) gas ports drilled into it close to the receiver. Like all MP5 barrels the MP5SD barrel is cold hammer forged with six conventional lands and grooves arranged in a constant right hand twist and is pressed and pinned into the receiver.

    The thirty gas ports in the MP5SD barrel vent propellent gases into the sound suppressor and lower the velocity of the bullet anywhere from 16 to 26 percent. This reduction depends greatly on the cartridge used.

    Located at the base of the attached sound suppressor is a 1 3/8 inch rubber 0-ring that seals off the back end of the sound suppressor. This O-ring should be checked for serviceability (complete and pliable) during inspection and should be replaced when the sound suppressor is replaced.

    The sound suppressor of the MP5SD was not designed to be fired full of water. The MP5SD-N “Navy” incorporates a stainless steel sound suppressor of nearly the same dimensions as the standard aluminum version that does allow it to be fired with water inside, should water enter the unit during an operation in or near water.

    Fitting the stainless steel MP5SD-N sound suppressor to the standard MP5SD requires the modification of the cocking lever support to account for the slightly larger diameter (@ .50 mm) of the “Navy” MP5SD sound suppressor.

    The special Barrel Cleaning Device (H&K ID # 225376) should be used to clean the barrel and gas ports of the MP5SD after every firing or every 500 rounds. If it is not used regularly the sound suppressor may become hard to unscrew or remove due to the excessive buildup of carbon fouling during firing, especially when using excessively dirty ammunition. (See “Normal Cleaning” of the sound suppresssor on page 53)”

    Credit r/MP5 – reddit 

    Below are two SD silencers. The one on the right is prepped for reinstallation with anti-seize grease.

    SILENCER SATURDAY #75: Cleaning The MP5SD

    SILENCER SATURDAY #75: Cleaning The MP5SD

    Notations, warnings and cautions from the operators manual:

    H&K MP5 Operators Manual – MP5SD

    Observe the following recommendations

    • DO NOT use subsonic ammunition in the MP5SD with a bullet weight of less than 140 grains
    • DO NOT attempt to open the sound suppressor body
    • DO NOT allow the gas ports to become clogged. Use the MP5SD Barrel Cleaning Device every 500 rounds to clean the barrel and gas ports.
    • DO NOT allow the sound suppressor to loosen during use. Do not use any form of tool or wrench to install or remove the sound suppressor. Sound suppressors should be hand tightened only. If the sound suppressor will not unscrew from the weapon, consult the section entitled “Normal Cleaning” of the sound suppressor on page 53 or call Heckler & Koch for guidance.
    • DO NOT fire the MP5SD, MP5/10 or MP5/40 with the standard aluminum sound suppressor full of water. Allow the water to drain from the sound suppressor before attempting to fire the weapon.
    • DO NOT fire the MP5SD without the sound suppressor attached.
    • DO NOT fire the MP5SD if the rubber O-ring is not present around the base of the barrel.
    • DO NOT attempt to fire the weapon if the sound suppressor has been dented or damaged or fits loosely on the weapon.
    • DO NOT exchange locking pieces between various models of the MP5.
    • DO NOT insert anything into the body of the sound suppressor such as a cleaning rod or brush.
    • DO NOT add to or fire the weapon with oil, grease or any foreign matter inside.
    • Keep the protective cap for the muzzle threads of the MP5-N, MP5K-N, MP5K-PDW, MP5/10 and MP5/40 on the barrel at all times when the sound suppressor is not attached. Store the cap on the optional holder in the pistol grip (H&K ID# 205483) when the sound suppressor is attached.
    • Keep the muzzle threads and threads of the sound suppressors and protective cap as clean as possible at all time to insure that the sound suppressor can be easily attached when required. Clean the threads with a nylon toothbrush or patch soaked in oil or solvent. Lightly lube the clean threads once they are clean. Dirty threads make it very difficult to attach the sound suppressor.”
    Credit r/MP5 – reddit 

    Now for the cleaning. Here’s the official barrel port brush recommended by H&K. If you click through the link, you’ll notice the brush alone costs about $120.

    Luckily there are alternatives. Here’s a battery terminal brush converted by my friend and dealer MAC Tactical.

    SILENCER SATURDAY #75: Cleaning The MP5SD

    SILENCER SATURDAY #75: Cleaning The MP5SD

    Properly attached to a length of PVC pipe, the brush can be run down the length of the barrel and on to the ports.

    SILENCER SATURDAY #75: Cleaning The MP5SD

    SILENCER SATURDAY #75: Cleaning The MP5SD

    SILENCER SATURDAY #75: Cleaning The MP5SD

    SILENCER SATURDAY #75: Cleaning The MP5SD

    Some SD cans, like the one from TPM, can be disassembled for cleaning. Using a spinner wrench, the end cap unscrews counterclockwise and the spacers and baffles are tapped out.

    SILENCER SATURDAY #75: Cleaning The MP5SD

    SILENCER SATURDAY #75: Cleaning The MP5SD

    After reassembly, use some high temperature anti-seize grease on the threads and the silencer cap face that mates with the sealing ring. Be careful, the stuff is messy.

    SILENCER SATURDAY #75: Cleaning The MP5SD

    SILENCER SATURDAY #75: Cleaning The MP5SD

    Reinstall the SD silencer on the barrel firmly to ensure proper seating. Enjoy for another 300-500 rounds.

    Have fun, be safe and we’ll see you next Saturday.

    Silencer Saturday is Sponsored by Yankee Hill Machine:


    Buy YHM silencers and accessories at:

    Silencer Shop – Hansohn BrOthers dead eye gun supply

    Mac tactical

    All YHM Products At Brownells

    DEALERS: If you want your link to buy YHM suppressors included in future Silencer Saturday posts, email: [email protected]

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    special Thanks: Mac Tactical


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    LE – Silencers – Science
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