I need to change out the Muzzle device on my MPX. Does anyone know if Sig uses any adhesive on their barrels?
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Sig MPX Barrel Glue
- Thread starter les_garten
- Start date
FWIW
18” breaker bar took care of my MPX’s. Unsure which compound they used.
The new Spears LT required 2 hr soak with hot water and 18” breaker barrel with Midwest Industries upper receiver rod.
18” breaker bar took care of my MPX’s. Unsure which compound they used.
The new Spears LT required 2 hr soak with hot water and 18” breaker barrel with Midwest Industries upper receiver rod.
Don’t be worried just have the barrel and receiver well supported.
Be VERY careful. There's all sorts of horror stories out there concerning the MCX line as they use Rocksett and on some, apparently, quite a bit of the stuff. Take the business end of the barrel and stick it in a bucket of water for at least 24 hours and make sure it's immersed past the muzzle device. Doesn't have to be boiling water as heat does not affect it (at that temp range). Use an action wrench or barrel vice and remove barrel from the upper receiver. DO NOT clamp the upper receiver as you could very easily damage it.
I was fortunate. I let mine sit for 48 hours and it came off with a loud crack. There have been people who have damaged their upper receivers trying to remove them. If that fails, can send it back to Sig and they'll remove it for you.
I was fortunate. I let mine sit for 48 hours and it came off with a loud crack. There have been people who have damaged their upper receivers trying to remove them. If that fails, can send it back to Sig and they'll remove it for you.
I don't think there is an action rod for the MPX. My barrel is 4.5" long, 9mm. The barrel separates from the receiver super easy. I got to look up this water/Rocksett thing?
Any AR action wrench should work I think? But it "softens" in water, just need to allow some time for it to get in there hence the 24 hour minimum soak time. They use it due to the high melt temp. Just do a search here in this forum for rocksett and plenty of threads will come up.
If heating it won't loosen it, it's probably rockset. As others have said putting it in water overnight works, evidently hot water works faster, but the real issue usually is how fast/well the water penetrates to the threads. Rockset is extremely heat resistant but loosens up with water, which is why it's somewhat popular for threaded muzzle devices.
Some of the Sig muzzle devices, MCX and MPX are on just ridiculously tight. I'd recommend using a barrel vice. So tight in fact I've read of quite a few folks with accuracy problems with MCX's that once they loosened the muzzle device and tightened it to a reasonable amount accuracy improved significantly. They were on so tight it seems they were deforming the end of the barrel.
Some of the Sig muzzle devices, MCX and MPX are on just ridiculously tight. I'd recommend using a barrel vice. So tight in fact I've read of quite a few folks with accuracy problems with MCX's that once they loosened the muzzle device and tightened it to a reasonable amount accuracy improved significantly. They were on so tight it seems they were deforming the end of the barrel.
These are some of the issues I am worried about. Also the barrel is so short you can't get a barrel clamp on it. No action rods work. I need to change the muzzle device but there are numerous accuracy issues associated with these barrels after being messed with. Somebody mentioned sending the barrel to Sig, is that really an option?
Pull the barrel and use barrel blocks. You can get barrel vise blocks for under $20 including shipping at Squirrel Daddy and cut them down as needed.
As I said above. 18” breaker bar was all that was need for our 2 MPX’s. I took the barrel and clamped it in a vice using magnetic plastic jaws around the gas assembly.
Best advise would be soak in hot water for 2 hrs. Have never needed more time than that with any Sig barrel we have MPX/MCX/Spear and some 10-12 barrels. Put in a vice, clock the gas tube against the side so that it won’t twist/move and use a long breaker bar with a tight fitting jaw. I have found on one occasion that a sharp tap of a metal hammer was needed. Give it a try.
I've got a monster vice(like 150#) and those magnetic pads. Like boil the barrel for two hours?
I suppose you could. I boil a cup of water then put the barrel in, don’t keep it boiling. Haven’t needed too. 2hrs has worked every time.
Crows foot wrench or similar on the breaker
I removed the muzzle brake from the 16 inch barrel. It's on there with RockSet. That was verified with a phone call to Sig.
Heat won't break it. You need to stick the muzzle in a bucket or can of water for 24 hours. Then you can remove it.
Remember it has a LEFT hand thread. To REMOVE the brake turn to the RIGHT!
Yeah, I'm scared to death I'll forget the thread direction. I need to put a post it note on my vise I think.
I was just thinking that also. Which can be a pain in the butt with certain supressors
After I soaked the muzzle in water it came off without any problem. I use the Sig pistol suppressor WITHOUT the spring for the piston. Use the sleeve that goes over the piston and it will stay on the barrel.
For some reason the fouling on the baffles and inside the tube was really hard. Nothing would take it off except; boiling the parts in vinegar!
You read that correctly. I disassembled the suppressor and boiled everything in vinegar in an old pot on an old hot plate in my driveway. I didn't want the smell of vinegar permeating the house.
Everything EXCEPT the end cap is boiled. I'm leery about the vinegar attacking the aluminum end cap. Besides, the fouling on that part isn't difficult to remove.
After you boil the parts, pour them and the vinegar through a strainer. The fouling will still be on everything. The next step is very messy but easier than trying to scrape hard encrusted fouling off everything.
I went to the bathtub and wore rubber gloves. You can use dishwashing soap or scouring powder. Apply the soap or scouring powder to an old tooth brush and scrub the fouled parts. Rinse in running water in the bathtub.
The fouling in the tube will be a little difficult to get to and sometime hard to remove but can be done. You might have to boil it longer than the baffles.
After you are done there will be a lot of black spots in your bathtub but scour it good before the SWMBO sees it.
I prefer this method over tumbling with water, steel pins, citric acid and Dawn dishwashing soap because I don't need to worry about separating the pins.
If you try the boiling vinegar method, let me know how it works for you.
Here is the Rocksett Tip Sheet from Flexbar (the mfg). The removal process is one small paragraph which says the same as others here, hot water for more than 20 minutes.
Rocksett Tip Sheet pdf
That said, one of Flexbar's technical reps posted elsewhere a number of years ago on removal. He said that Rocksett is crystalline in structure and will fracture when subjected to heavy shock. He mentioned how one of the biggest names in AR manufacturing, who uses Rocksett, removes their muzzle devices. They smack the end of the MD with a BFH and it screws right off. Not sure that I would have the guts to do that, seeing that I would have to pay for any damage.
Rocksett Tip Sheet pdf
That said, one of Flexbar's technical reps posted elsewhere a number of years ago on removal. He said that Rocksett is crystalline in structure and will fracture when subjected to heavy shock. He mentioned how one of the biggest names in AR manufacturing, who uses Rocksett, removes their muzzle devices. They smack the end of the MD with a BFH and it screws right off. Not sure that I would have the guts to do that, seeing that I would have to pay for any damage.
A few pix of the project.
I call this the Secret Squirrel addition.
I call this the Secret Squirrel addition.
I may smack it with a dead blow hammer before the hot water therapy.
Are you removing the flash hider from the short pistol barrel or the 16 inch carbine barrel?
If so, I don't recall the flash hider on either one of my 4.5" and 8" barrels being difficult to remove at all. The Carbine barrel required the water treatment.
The pistol flash hiders came off rather easy AND they are still LEFT hand threads.
I didn't have any issues with my mpx mounting a can on it. Just soak in hot water for 2 hrs in case there is rock set and Clamp the barrel down and break it loose. A good smack to brake any bond also never hurts
Its been a while since I did mine, but I seem to recall it was easiest to pull the barrel out of the receiver and clamp the gas block with soft jaws to hold it.
Well, 2 reasons.
1) A joke, I called it the Secret Squirrel edition. Hint -- Look up Secret Squirrel on youtube
2) I am going to take it to the range with that scope to verify accuracy before and after the muzzle device swap. There are a lot of issues there and I have to know if I am moving in the right decision with my muzzle device and suppressor.
I'll probably know if I am having issues without it, but it's QD so no big deal to pop it on and off.
I have a Holosun 510 that will live on it afterwards.
With the short barrel, you may find that the accuracy gets down right awful after installing a suppressor. That was my experience.
I can't find the video now but the MAC channel on YouTube had the same problem.
I discovered, before he did, that going to a longer 8" barrel solved the accuracy problem. I also removed the shorter key-mod handguard and put a MI M-Loc one in place.
So with the 8" barrel the braced pistol shot great. Then after the pistol brace issue raised it's ugly head, I decided to convert it to a PCC and couldn't be happier. I should have bought the PCC in the first place but we all live and learn.
I know that I won't be able to talk you out of it but will say that you will probably be wasting ammunition if you try to shoot the 4.5 inch barrel with a suppressor. Regardless of that, please let us know how it works.
It actually wasn't the suppressor. They had the problem with the muzzle device. Problem was they attached the MD to use with the suppressor, so they added them at the same time. They spent a lot of troubleshooting time blaming the suppressor. I spent a lot of time getting what I think is the right muzzle device. They have to locate on the taper. If they just screw down and don't index off the taper, it's a chit show as soon as the MD is attached. I mean REALLY bad. The other mistakes made were running pistons and springs when they shouldn't have with a fixed barrel. Also most of the problems came from the tri-lug muzzle devices. The Sig barrels are known to be real accurate, so I want to try and make that work. I bought a JMAC Muzzle device made for the MPX. Got my fingers crossed as well as a very expensive MD in my possession. Lots of really ugly threads on this subject.
I really am gonna shoot it with that scope the first time out. Then again with the muzzle device changed out.
I didn't use the muzzle device with the suppressor. Mine is a Sig SDR9 and it's a direct thread. You are correct, the barrels are very accurate. However, both me and MAC had the same problems. He was also using a direct thread can, IIRC. I wish I could find that video.
Since I converted it to a PCC, I haven't had any problems and am able to hot a 10 inch steel plate at 100 yards about 80-90% of the time.
Some of the direct thread cans had "various stuff" between the can and the barrel.
Wish me luck, I want to run my Wolfman on a KeyMicro system. I did get the MI 8" Handguard real cheap at DVOR this week.
Smack it after, when the water has had its chance to work. You could be putting undue stress and impact if you do it before. Like I said above I did have to do this once.
You will be good man. Soak it and smack the end of it and brake that baby loose. You will be fine.
He's just asking you about the type of breaking bar or wrench you are using. Length of Rachel or breaker or whatever
Ahhh, ok. The barrel removes super fast with a few torx bolts. I have that big azz vise with the plastic jaws I'll chuk it up in. Then use a breaker bar with a crows foot it think. First thing I may try is a long pattern 19mm open end wrench just to see if it breaks easy and get an idea of how tight it is. I believe the birdcage is 19mm.
Ah. Size matters. Lol. I found less than 18” made removing any hider more difficult. Longer arm = less felt force/effort.
My MPX was a "First Responder Edition" made in Jan 2023. It had a Sig trigger in it. Heavy, Heavy, Heavy. About 8 1/2 - 9#. Felt good, just Heavy as hell.
Put in the Geissele SSA MPX tonight and went to about 4 1/4#.
Had ordered some 20rd magz to shoot it off some bags but the place I ordered them from was a scam sight I think. So re-ordered those and will have to wait to shoot it.
Put in the Geissele SSA MPX tonight and went to about 4 1/4#.
Had ordered some 20rd magz to shoot it off some bags but the place I ordered them from was a scam sight I think. So re-ordered those and will have to wait to shoot it.
I shot the stock muzzle device and it easily grouped under 2" with a 2 MOA red dot at 25 yards.
The muzzle device came off really easy. No glue.
I put on my JMAC muzzle device and I'll shoot it again with the same ammo to see if I have any accuracy issues with the new muzzle device.
JMAC Brake
The muzzle device came off really easy. No glue.
I put on my JMAC muzzle device and I'll shoot it again with the same ammo to see if I have any accuracy issues with the new muzzle device.
JMAC Brake
Shot it today with the new Muzzle device and it was around 1" for 5 shots at 25 yards. So next month the range where my Wolfman is being held hostage will be renovated and I'll shoot it then and we'll see.
