Looking for real-world experience with the main MPX FRT options. My current setup is rare breed + Frankenstein trip bar. From what I’ve found, these are the options out there.

- Cassette-style FRT (Rare Breed, DTT, Partisan Disruptor/LAT) + trip bar (Frankenstein armory, Parker Mountain Machine). It’s extremely reliable (2k+ rounds), but trigger slap and mushy semi auto trigger are bad enough for me to be making this post. - I only have experience with the rare breed and delta team tactical FRT so can’t speak to the disruptor/LAT.

- AS Designs Arc-Fire V2 / MPX Slip Trip: Selector/cam-style forced-reset system that can retain a conventional trigger. Seems appealing for better semi-auto trigger feel and potentially less trigger slap, but appears more sensitive to tolerances and individual MPX configuration.

- Atrius Development X-Series FRS: Newer purpose-built forced-reset selector system designed around SIG platforms. Seems like the most integrated approach, but it’s new enough that there isn’t nearly as much long-term or high-round-count feedback yet. Very interested to see how these turn out.

For anyone who has actually run one or more of these in an MPX, which would you choose and why? Mainly interested in reliability, trigger feel, trigger slap, durability, and overall experience. Please include MPX generation and approximate round count if possible.

New to the platform here, confused about the basepad and magazine compatibility. The TTI website says this only works with the Thril magazines, but the mags I found on Gunmag Warehouse doesn't say Thril, and says it's Sig OEM. I also found somewhere else that says "Thril 35 round magazine Gen 2". Does anyone know if the TTI basepad is compatible with the magazine in my second screenshot? Thanks!

Mostly cosmetic but I like it.

Sbr stamp just got approved

Just needs an frt.

Mpx k

4.5” sig barrel with ilwt adjustable gas plug

Boe incolite 9

Comstock armory recessed plan b mount

Rearden mini plan b muzzle device/adapter

MI iron sights

Surefire scout

Schaffer surefire/ qd sling mount

Surefire picatinny mount to bridge upper and keep things tight

Arisaka indexer

Aimpoint t2

Scalar works mount

Ilwt ejection port cover

Driven arms co UCG

Taccom buffer pad

Reptilia puller charging handle

Pmm kate moss stock

Painted some plastidip on the uppers front takedown pin mount and inside the receiver connection to solve the upper/lower play.

Anyone rocking this FRT?

It got out of jail in 4 days not bad 😍

It's just a magpul qd sling mount torqued to 45 in lbs bridging the gap between the upper and the rail... Zero noticeable rail wobble now, I'll see how much moa shift my IR laser has soon but I don't expect it to be that much and should definitely be adequate for the distances I'd take a shot with 9mm.

Do ronin setups still exist? I haven’t seen any for sale recently and went to there website to see if I could send in my setup soon but the the conversion service is OOS. I am mainly looking to get the barrel ported because i haven’t seen a lot of positives about the ILWT SD barrel.

I recently got a MPX K and took it to the range today. When putting the mag in sometimes the round wouldn’t go into battery and I would have to rack it back hard to do so. Is this a common problem or do I need to upgrade/replace something?

Anyone using one of these with the ILWT SD barrel? I have a Rugged Obsidian 9 that I’d like to use for it but idk if it will have enough room considering the blast chamber is smaller than other cans. Can anyone tell me what the length of the barrel is from the outer threads? I sent an email to ILWT a few days ago but haven’t heard back yet.

To all the people who have a direct mounted 9k is this all you need?

What a beast. Thought I’d share.

Run this combo for direct amount ilwt taper along with M13.5X1LH TO 1/2X28 adapter

Had anyone done this? Good idea bad idea?

Anyone have experience with either or preferably both of these charging handles? Which do you prefer? Notice any difference in either while running suppressed?

I been doing a little research on getting a suppressed MPX K. I want to keep the stock barrel. The suppressor that I want is the Huxwrx flow 9k. Heard a lot of issues with accuracy when people use the tri lug. I just want to direct mount this suppressor. I do not plan on taking the suppressor off. What do I need to get to make this fit?

Care to share your results with this set up or have something similar. My goal is getting a suppressor under $800 price tag and not get gassed to much. Also plan to get the radian charging handle.

Such a fun gun!

Is amazing. Recently bought an mpx k. Put 500 rds through it on day one,m, with the floppy and just not good stock charging handle. Ordered the reptilia puller the same day. 500 rds last range day and the reptilia is way better, Plus it’s the perfect size and is pretty much the same as the G$ changing handle on my ar. Would highly recommend.

Now just waiting on silencer shop to do their job and ship my can… Went with the rearden plan b 3 prong flash hider and I picked up a titanium plan b to hub adapter.

Hello everyone Im wanting help in adding an attachment. Im wanting to buy this suppressor ( https://www.silencercentral.com/products/silencerco-omega-9k ) for my 8inch MPX shown in the photo. I'm wanting to also know if I'm needing any other parts or if i can just screw it on? Thanks!!

Still gotta get a better optic and switch away from tri-lug but I like how the rapco accents turned out.

My First Sig Acquisition! Been On The Wish List Some Time Now And Finally Had A Reason To Pull The Trigger.

June 2026 Production Sticker, 3rd Gen 8” MIL/LE