MCX Virtus .... Brass over bolt malfunktion.

Metal dummy rounds of the correct type have run flawlessly through my MCXs.

The charging handle on the MCX has dual latches that move in unison. What I would do in your place would be first separate the upper from the lower by pushing out the take down pins. Then see what you can see if anything. Next comes the rubber tipped mallet. With one hand make sure that the dual latches on the charging handle are released and the other hand can give a good whack to the other side of the charging handle. Repeat as needed.

I wonder if you disassembled the bolt carrier and got the extractor on the wrong side on reassembly. The extractor goes on the right side looking down the barrel form the shooter's position. Personally, I would not hand over an MCX to a smith or armorer that isn't experienced working on the MCX. It's a bit different from other ARs as it is an AR180 design of sorts and not an AR15.

Bill

Thx for the replays.

@ Littlejacks I can pop the takedowns and separate the upper reciever. But i cant remove the recoil assembly as i cant move the charging handle enough. It stucks very firm with hardly any possible movement. 1-2 mm that´s it. I need to move it at last a few cm to remove the assembly.

@MrMcGoo I think now, the plastic ones were a bad idea, too! Coming from pistoles I just started with a long gun. I tried the "wacking" before but as there is no movement on the charging handle possible so nothing happend. This idea seems to work at " normal" AR as i saw at youtube, but not at a MCX. And as i never disassembled the gun before this fault cant be.... everything worked fine until i added this §$%$§ plastic dummy rounds! Next friday i will visit my smith who "married" the optics and the gun. I hope he can help. I will post her what will happen. ;-)

Understand SIG manual's instructions applies to a normal status with the bolt locked into the barrel extension. You've described a very different condition with a plastic round jammed inside the breech. Seems unlikely your bolt is actually locked in the barrel extension as anticipated by the manual's instruction.

Removing MCX barrel is an easy, loosen 2 retained torx fastener procedure. Your particular jam may have placed the barrel extension in a bind, making the barrel difficult to remove, but it's an easy <5 minute task to try.

It's only a suggestion, something I would do with no risk of damaging the rifle. If you're uncomfortable that's fine, I'll suggest calling SIG customer service before going to a gun smith. Am sure they'll get you fixed. I mention SIG because while MCX looks like an AR15, it's action components are very different. You don't want a smith's initial MCX experiance to be on your rifle.

Sadly, seeing a photo of your broken receiver on Sig Talk wouldn't be the first we've seen here..

Cheers