Wondering if you could use RLL with Sig MCX?
It does look like an AR type of firearm... any thoughts?


Pix borrowed from Sig section of AR15.com

I guess the first question is if it'll physically fit, and function in the same manner.  Without dimensions and pics of the internals I couldn't hazard a guess.

Bingo.  

An RLL requires an sp1 bcg.  An mcx doesn't use a standard bcg, so I very much doubt it would work in the first place.  I too would like to see an internal picture or schematic of it though.  Damn things might not even work with a DIAS

Gotta know it it would even fit and function before thinking about whether it would be legal.  My guess is that it wouldn't be anyway, but I'm not sure.

Folding buttstock means it's going to require a forward mounted sear trip.  I would say that's probably a no-go for a LL or DIAS.        
 

I have to say, it looks pretty sweet.  Any word on release date or MSRP?        
 

Out of the box the answer appears to be no.

Look at the BCG and how short it is.  While the rear lug could be used to trip the link, the bolt carrier is too short.

That said, from a mechanical perspective I suspect that you could make a trip that could actuate a link.  Think of a scaled  up sear trip similar to what is used in a Ciener M16 22LR kit that sits in the upper and the bolt carrier hits which in turn trips the link paddle.

Whether it would all be kosher per the ATF, I don't know but I suspect the answer may be No.

Teardown pics of the MCX below

http://www.recoilweb.com/recoil-exclusive-breakdown-of-the-sig-mcx-56367.html

Very interesting sear trip extension on the 5.56 version.

Indeed, interesting!  With a modified sear trip extension, it might be possible to make it work with an RLL.  After that the next question would be if ATF would consider doing so to be "making a new, post-86 machinegun" out of the combination.

ETA: If it works with what looks to be standard M16 FCG in the lower, it'll almost certainly work with an RDIAS.  Same question as above about legality would remain.

If a Ciener is kosher, this should be too.

I had wondered the same about the MPX model coming out.  Have yet to see the inside of one of those but I do know standard AR/M16 FCG parts work.  I tried to look inside one at the SHOT show last year and stupid me I asked if I could open it and the guy said no and why I wanted to.  I told him I was curious if a Geiselle trigger would work and he said the SSF was tested and worked fine.   If it is the same as the MCX pictures linked here it might work.  Not sure if the ATF would allow or not.  They did approve the use in the Colt 901 (someone here posted they have a letter at least for themselves) and that is a little different than a standard AR pattern firearm.

That is ingenious. I look forward to putting one on my M16 lower.