Sig MPX - Cleaning?

[ZOSO]

Hi all.  I just purchased a Sig MPX.  It will be a competition gun.  I clean my competition guns after each match, and plan to do the same with the MPX.  Just wondering if the gas plug and piston should also be cleaned after each match.  How often do you clean your gas plug and piston?  Thanks!

 

Edit: I plan on shooting plated bullets. 

Edited June 12, 2022 by ZOSO

[fbzero]

For the MPX, it seems to depend a lot on the ammo you shoot.  FMJ's with a relatively clean powder and you should be good for at least 1-1.5K before needing that.  They don't recommend coated bullets, but I've gone over 1K with Blue Bullets and had no issues, but would still do it at 1K to be safe.  Used another brand of coated bullets a year or so ago and they gummed up the works and caused constant malfunctions within 100 rounds.

[ZOSO]

5 hours ago, fbzero said:

For the MPX, it seems to depend a lot on the ammo you shoot.  FMJ's with a relatively clean powder and you should be good for at least 1-1.5K before needing that.  They don't recommend coated bullets, but I've gone over 1K with Blue Bullets and had no issues, but would still do it at 1K to be safe.  Used another brand of coated bullets a year or so ago and they gummed up the works and caused constant malfunctions within 100 rounds.

 

Thanks fbzero.

[Shootingaggie]

Syntech 150 required cleaning gas port often if want to run reliably. 
 

I have a question in this similar vain, what is best method for cleaning comp. that thing is starting to get a lot of build up. 

[fbzero]

12 hours ago, Shootingaggie said:

Syntech 150 required cleaning gas port often if want to run reliably. 
 

I have a question in this similar vain, what is best method for cleaning comp. that thing is starting to get a lot of build up. 

 

Soak and scrape has been my method.  I've seen some videos on YouTube suggesting that an ultrasonic works well if you have one.  

[Polaris13]

For sure clean the gas port every time you clean.  I let it go once and the headache wasn't worth it.  Yes it takes extra time....

[davebenson]

Hi. I shoot an MPX in competition and have over 50k rounds through one. 
 

I tested to find failures due to not cleaning. At about 1,800 rounds I get light primer hits. Clean the firing pin channel in bolt good for another 1,800

 

during multi day matches I clean the bolt and bolt carrier light oil and good to go. 
 

I remove and cleans the gas port at the 3-4k mark.  Any more and I find the rings start to carbon up and it is a pain to free them.  I soak parts in oven cleaner.  
 

if the gas plug get too much carbon it can impact timing and could cause jams worse case bent op rods. 
 

there is a new FB group called Sig Sauer MPX discussion. 
 

lots of good technical information shared there 

Edited June 24, 2022 by davebenson

[davebenson]

Fixed spelling 

[Bdh821]

a clean gun is a reliable gun...  I take the gas piston/plug out every 1500ish rounds.  Wipe down BCG every 500ish.  I dont recommend painted bullets.  I recommend using Alliant Sport Pistol powder with 115s or 124s around 140pf.  Make sure you clean the expansion chamber on the gas plug.  Clean the side ports on the gas block clean.  and behind the extractor.  otherwise the rest is pretty straight forward

 

[davebenson]

25 minutes ago, Bdh821 said:

a clean gun is a reliable gun...  I take the gas piston/plug out every 1500ish rounds.  Wipe down BCG every 500ish.  I dont recommend painted bullets.  I recommend using Alliant Sport Pistol powder with 115s or 124s around 140pf.  Make sure you clean the expansion chamber on the gas plug.  Clean the side ports on the gas block clean.  and behind the extractor.  otherwise the rest is pretty straight forward

 

Have you ever let cleaning the gas plug/port and piston ring go a little too long?  I have and ended up replacing the piston and rings.  
 

if they are really full of carbon I let them soak over night in oven cleaner.  It is designed to soften carbon in ovens and won’t damage any parts. 
 

I use a welders tip cleaning wire bent at 90 degrees to get into the gas port. 

[Boomstick303]

On 6/12/2022 at 7:26 PM, Shootingaggie said:

what is best method for cleaning comp. that thing is starting to get a lot of build up.

 

I do not own a MPX, but for the JP I own I had horrible lead build up that needed to be removed.  I used the mixture named on here numerous times.  Peracetic acid, which is a mixture of Hydrogen Peroxide and White Vinegar.  I used a 50/50 mix.  Note this is acid and can do some damage if not used right.  Use breathing protection, and in a well ventilated area.  

 

After soaking over night, I used a Dremel Engraver where I modified the tip into a chisel shape. When I felt the Engraver was having a hard time removing any more lead, I would soak for another hour or two and repeat the process.  The Dremel Engraver did not damage my comp, but my comp is Titanium or stainless.  If you have a DLC or similar coating the Dremel engraver and the wire brush may damage the finish.  

 

I also used a Dremel with a wire brush bit to do the final cleanup.  

 

Comp came out like new.