I know you guys said the SD guns are dirty but oh man. I only shot about 300 rounds of WWB (I know, I know...) but the entire thing is covered in carbon. I’ve shot suppressed ARs for over a decade and never experienced anything like this

Are there any particular areas of focus needed for cleaning on the SD platform? Muzzle threads, bolt, etc? Anything special needed for the can itself? I am not the type to completely disassemble a gun every time I am done shooting to clean it, but I want it to be reliable and maintained so I’d appreciate any info on what to focus on.

I just clean like a normal gun beyond using a battery terminal brush attached to some PVC for the barrel and threads.

Yes it gets really dirty.

I stopped cleaning my can a long time ago. It was just more trouble than its worth. I just take a rubber mallet and hit it around the can to try and get the powder debris out over a trashcan. Everytime I cleaned it I would get wild accuracy for a few hundred rounds.

I might be a bad parent, but I don't really clean mine much.

Old terry cloth towels... spray aerosol cleaner / clp... clean it the best you can then dont sweat it.. it was designed to operate like that.

In another world, I was a MP5SD gunner.

1.  Semiauto or two round burst only except in dire emergencies.

2.  By 500 rounds w/o cleaning, you are going to start getting failure to extract and failure to eject frequently.

3.  Anytime in the field setting that you can wipe down the bolt carrier and bolt, do so.  CLP is your friend.  Chamber cleaning and spray out the chamber flutes when ever time and situation permit.

4.  non-seize on suppressor threads will make life easier.

5.  Eye pro at all times, I used to look like a Finnish racoon at the end of shoot house session.

6.  Clean your magazines, the carbon and unburnt powder will quickly build up on the magazine follower.

 Bottom line, the SD is like a redhead, It's finicky and a bitch when dirty, but it will rock your world when you take care of it.

18Z50...old school Nous Defions before it was trendy

HK recommends cleaning the SD every 300 rounds. I noticed a post on another site at least 10 years ago. The owner had not done so well at prepping or cleaning. Carbon had built up on the mounting threads of the barrel inside the can. It was so hard that when he used a strap wrench to remove the can, the end cap remained on the barrel and the can unscrewed from the end cap. I think the owner ended up sending the gun to a Smith who had to press out the barrel because the owner could not get at the threads through the cage to clean the mounting threads enough to get the end cap off the barrel. Over the years I have seen several owners post of the carbon in the mounting threads on the barrel galled the mounting threads from carbon buildup on the threads. I use the notched O-ring and high temperature grease on the mounting threads of my SD barrels. I have three 9mm SDs so after 300 rds, I pull the can and put it on another one. Doing so is expensive but effective. I don't do that very often because it makes for a lot of cleaning SDs. YMMV.

Scott

I used this thread to build my own barrel port brush.

https://www.hkpro.com/threads/mp5sd-%E2%80%93-barrel-port-brush-tool-build.257233/

Thanks for all of the replies guys. This is very helpful. I never considered anything to do with the ports.

What about ammo types? I have heard ammo with exposed lead bases is the worst. Any truth to this?