According to SIG, they have decided to do a Mandatory Recall of the MCX to upgrade the Carriage Assembly. Read about the recall from SIG:
SIG SAUER is conducting a mandatory replacement of the carriage assembly in SIG MCX rifles. SIG has found through extensive factory testing that in extremely rare instances, not reported in the field and extremely difficult to replicate, a condition may exist causing an unintended discharge. Failure to follow the loading procedures and basic rules of safe firearms handling outlined in the user’s manual has the potential to cause serious bodily harm or death. Although this has only been witnessed in 300 blackout, SIG has decided to upgrade all MCX models since the MCX is a modular platform and we want to ensure the quality and reliability of all products we manufacture.
Stop use of firearm immediately, and visit the SIG SAUER website listed below as soon as possible to register your firearm, initiate the process and view a video explaining how to change out your carriage assembly. SIG will send you a prepaid box to return your complete carriage assembly to the factory. A new assembly, designed with the firing pin locking mechanism, will be shipped out to you within 5-7 working days of the receipt of your parts at no cost to you. Please note total in transit times will vary based on geographic locations. SIG will also send you a $50 gift voucher for any inconvenience this may have caused. This upgraded carriage assembly addresses this potential issue while enhancing the performance and longevity of your rifle. You may also contact SIG SAUER customer service at the number below with any questions if needed.
SIG SAUER is committed to addressing this issue in an expedited manner, and appreciates your support.
Firearm Registration – https://www.sigsauer.com/support/warranty/warranty-registration/
For Customer Service – 603-610-3000: Option 1
For Instructional Video – https://www.sigsauer.com/press-releases/mcx-mandatory-carriage-assembly-replacement-program
*Serial numbers 63C000044 – 63C003702 – Contact SIG Customer Service for instructions.
*If you have replaced your trigger group with an aftermarket trigger please contact SIG Customer Service for instructions.
*SIG SAUER Dealers should call designated Commercial Sales Support Representative.
**Any MCX rifle with a serial number ending in 25000 or higher is exempt from this program.**
If you have any questions, comments, or concerns, please contact SIG directly or contact your nearest SIG Dealer. Here is what they are changing Gen 1 Version is the original and the Gen 2 Version is the updated one.
It looks like the firing pin removing pin is non-removeable, the firing pin has a spring attached to it, and the cap rod is being changed from dovetail to dog leg type attachment. Hopefully with this recall, it won’t damage this popular rifles reputation.