Sent a msg to SIG asking:
How do I get the adaptor to use the MCX upper on the AR lower? I want to put a MCX pistol upper on a SBR registered AR lower. The adaptor allows for the use of SIG buttstocks and holds the recoil springs and rods in the upper.
Is the adaptor required? One SIG commercial shows it being used and the newer commercial (viewed this week) doesn't show it being used on the AR lower. Looks too dangerous to not use the adaptor with the resulting unsecured op rod springs and rods aimed right at the shooter's face.
Why is the original MCX advertised as a 50,000 round firearm and the improved version, the Virtus, only rated at 20,000 round before parts replacement? I suggested they show this to their marketing people.
How do I get the taper cap adaptor to mount a non-SIG suppressor on the MCX 5.56 bbl?
How do I get the trip lever that allows the MCX upper to function full auto on the M16 lower? The uppers are already cut for the trip lever. The SIG bolt carrier, upon going forward, pulls the trip lever which then pulls the auto sear if the selector is set to AUTO.
FWIW, the msg was sent direct to a SIG employee who just posted a video saying send questions directly to him.
Well, I actually got a REPLY from SIG. Note that I did not say I got ANSWERS to all my questions! Don't you just hate it when your question is not answered or you get an answer instead to a question you didn't ask?
1) An adaptor to use the MCX upper on an AR lower is required. One answer I got implies to me that if you buy an upper you get the adaptor ("The uppers all ship with this piece."). I was not told how to get the adaptor if you already have a complete MCX that you want to use the upper on your AR lower. I will ask the question again.
2) No reply to why one commercial shows the adaptor in place and another one doesn't show it.
3) Trip levers for full auto fire aren't available for sale. Guess if I ever got the AR upper adaptor, I could try and make a trip.
4) Taper cap suppressor adaptor is available through customer service.
5) One has to interpret their ads/statements VERY carefully. It turns out the up to 50,000 round life only refers to the receiver itself, not any of the other parts attached. Here's the actual quote: "On a rifle such as the MCX, which was required to have an upper receiver that could fire up to 50,000 rounds before failure, it is important for parts to last." Dummy me, I read that and thought the whole upper had a long life. The 20,000 rounds of the Virtus refers to all parts.
Edited to add: I suppose companies sometimes dislike people like me for asking probing questions.
Last edited: