Quoted:
Hey Guys - just to eliminate any confusion here, let me shed some light:

The Virtus now uses a tapered bolt.  The carrier is exactly the same.  MCX barrels WILL work in the Virtus, you just need to use the M16-style bolt that is in current MCX.  The new Virtus barrels use the new tapered bolt.  The barrels are designed so that if you put the wrong bolt with the wrong barrel, the weapon will NOT go into battery.  If you buy a CALX/barrel kit going forward, it will be a Virtus model and WILL come with the tapered bolt required to use said barrel.

We WILL continue to support the MCX.  We have tenders and contracts on this gun and it will be in our production schedule for a long time. Support for the MCX is NOT going away.  Handguards, etc will continue to be produced and be available.  So, if you do not want to (also/upgrade to) purchase a Virtus, you will be perfectly fine with your existing MCX.

The Virtus/MLOK hadnguards have a much better lockup/solid lockup, which now allows you to mount lasers/optics/BUIS, etc onto the rail sections and allow them repeatability/return-to-zero.  

Honestly, the only "issue" you're going to run into is that the new MLOK hand guards are the only thing NOT compatible with the MCX.  Reason being, the upper/chassis of the MCX is longer than that which is on the Virtus going forward.  So, while the attachment points are the same, the top rail on the MCX is too long for the new hand guard.

Make sense?

Quoted:
I remember reading that the original MCX rail should not be used to mount lasers and iron sights because of zero shift.

Does this still hold true with the new Virtus?