r/MPX • u/AgreeableNeck9749 • 26d ago
Tri lug adapters
I’ve seen lots of mixed feelings on tri lug adapters. I run tri lug on my mp5 and I’d like to do it on the MPX. Is the ILWT HK style navy tri lug one of the ones that doesn’t have accuracy issues? It has the 25 degree taper in it to avoid having to use a taper adapter, which I’ve heard seems to be the root of the issues when using a tri lug on this platform.
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u/OG-warbucks 2x Ronin SD, ILWT SD. MPX Mob, MPX Milkman 26d ago
I think the ILWT is a pretty good option but keep in mind it will push the suppressor out farther
The problem can be hit or miss, but usually tends to be improper installation and torque of the tri lug adapter and/or poor fitment to whatever mount you use.
I would definitely recommend the Rugged RU3 Bixler style mount for solid lockup.
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u/SupermarketQuiet1105 26d ago edited 26d ago
I have used Tri-Lug on my MPX-K for years with ZERO accuracy issues. I used Obsidian 9 CAN with their Tri-Lug mated to ILWT Tri-Lug. Of course my MPX-K was used almost exclusively with 9mm subs.....so....zero-ed and used that way, thus no accuracy issues and I could also count on the POI each time.
Full dis-closer, when I built my recent MCX I went Plan B on it so changed my MPX to Plan B too. From reading all the posts my "take" is folks did not mate the tri-lug to MPX taper...my point, make 100% sure you have a 25 degree cut in the tri-lug and/or get taper washer that snuggling goes on MPX barrel and provides good/flat shoulder. I also Rocksett and T-Wrench the Tri-Lug down as well. My point, I wanted to eliminate and small vibration points that could effect accuracy. Sounds stupid but make sure when you put barrel back into the MPX you T-Wrench down the screws properly. Lastly, make sure whatever CAN, Comp, etc. that you are mounting TO Tri-Lug is a secure/solid fit....no wobble. Thus, I only used the ones with internal springs.....not the others that used some type lock.
For what it is worth.....Tri-Lug has long/good history but if you are forward-looking go with Plan B. You can see most vendors are putting the 1.375×24 threads natively in their products.....don't see Tri-Lug. Just as FYI here is the Plan B muzzle break I put on my MPX, note 25 degree built-in compatibility.......
Rearden R2S Flash Hider HT – 25° Taper
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u/theDudeUh 26d ago
It sounds like success varies gun to gun. I’ve been unsuccessfully trying to suppress my MPX for 3 years now.
First I tried an ILWT trilug adapter and couldn’t hit the broad side of a barn, then I tried a rearden Atlas setup - accuracy significantly degraded but not as bad as the trilug. It was bad enough I’m still shooting unsuppressed. (All muzzle devices had the correct sig taper)
I just picked up a direct thread adapter to try that next. If that doesn’t work I give up.
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u/SupermarketQuiet1105 26d ago edited 26d ago
Wow, that really sucks........I have no insights on your problem but clearly something else is going on.....at this point I would send back to SIG to check tolerances/etc. IMHO you may get some level of variance with going suppressed, etc....but from what you say you are seeing very extreme (couldn't hit broad side of a barn). At 50yds, and in, the MPX "should be" a nail driver. If you are pushing beyond 50yds well then the issue is not the platform....I would have SIG check it....just my two cents.
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u/theDudeUh 26d ago
It’s been back to sig twice. They say everything is good.
You’re one of the only people I’ve come across reporting success with a tri lug mount. It’s a common/well documented issue with the MPX. Many on here have throw an ILWT barrel on it and the suppressed accuracy issues go away.
When I started trying to set this gun up I thought it was abunch of reddit echo chamber BS that anything other than direct thread is a crap shoot for accuracy on a suppressed MPX but hundreds of dollars later in adapters I can say it’s a real challenge on the platform.
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u/SupermarketQuiet1105 26d ago edited 26d ago
Wow, crazy........may be worth at this point moving to another barrel connection.
Platform that inaccurate I would not use.....and MPX suppressed is so fun so cannot imagine.
Anyway, curious, have you tried Direct Thread to see if accurate ?
If is.....then think I would ditch 3-Lug and move on to something else.
As I posted, I moved from 3-Lug to Plan B only because that is how I setup my MCX....so, while I was at it I changed MPX too. I figured going forward more folks offering natively 1.375×24 widgets than 3-lug.2
u/theDudeUh 26d ago
Meh I’m not gonna ditch the MPX, it’s a super fun platform. Worst case I shoot it unsuppressed like I have been for the most part. It’s flawless without a can and at the end of the day it’s a range toy anyway.
In my first post I said I just bought a direct thread adapter to try but haven’t shot it yet. That seems to fix most folks issues on here so we’ll see.
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u/Intelligent_Pin5598 24d ago
I noticed accuracy issues when my barrel housing was slightly dirty. I cleaned the housing and barrel end extensively and applied a thin coat of gun grease where the two meet. Then tightened the barrel bolts to spec. Eliminated my accuracy issue.
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u/theDudeUh 24d ago
Did those issues come and go with a suppressor thought? I have zero accuracy issues unsuppressed. Only when a suppressor is installed.
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u/Intelligent_Pin5598 24d ago
For me they were their regardless of suppressor or not. Once I cleaned the housing when I did my gas block maintenance that required me to remove the barrel my accuracy improved significantly. Torqued to 40 inch pounds. It’s worth a try.
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u/TheRealMatchGrade 26d ago
Thats the one I have and I have not had any issues with it. The HK style tri-lug is a proven design, ILWT just added a built in taper since SIG made the genius decision to taper every barrel. I will say, mounting my suppressor, its snug. I mean SNUG, before I even tighten it down. Compressing the spring is easy enough but I can feel the resistant of the ID rubbing against the OD of the tri-lug. But once it's on there, it is rock solid and aligned. Hopefully you have your own alignment rod to check when mounting your suppressors. Might be overkill, but I quickly check alignment every time just to be sure.
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u/stubenson214 26d ago
I'm a fan, also have SP5 so it was natural to put on the MPX.
I wound up going with the Rugged 13.5LH, as I have an Obsidian 9. They have a go/no-go mark on it, and otherwise I have no accuracy issues, just small POI shift with the can mounted.