Ppl
The people that got the original MCX where the beta testers.. Sig even changed the name to Virtus they changed so much lol
I'm not sure they were beta testers since the beginning the MCX was designed at the request of SOCOM by the designers of the HK416 as an improvement upon it.
The major generational changes to the MCX the improve or change performance have been;
1. The recall of the Legacy which was done to give the MCX a spring loaded firing pin to alleviate firing pin stirkes on one particular type of out of spec 300 BLK ammo with soft primers Chris Bartochi clarifies this in his video of the Legacy on his YT channel Small Arms Solutions. There was no issue with 556 guns that was resolved during the recall. However as a result of this recall the MCX lost compatibility with both standard AR15 triggers and bolts.
2. The Virtus comes with a better trigger than the Legacy's which stunk however again you lose compatibility with standard AR15 triggers that the original MCX had.
3. The Virtus comes with a better charging handle. Giessele makes a Legacy MCX charging handle
4. Both guns came with the same CHF nitrided barrels however Sig added approx 8oz the barrel profile of the Virtus. My guess is that Sig did it to meet SOCOM's 1.5 MOA at 300 yards even after 10,000 rounds on the barrel requirement. In reality adding 8oz to a barrel profile will make accuracy improvements but it won't make an inaccurate gun sub MOA the improvements will be marginal. As stated in an earlier post I don't have a need to heat cycle the suppressor up to 900° on full auto and then meet accuracy requirements..
5. Sig beefed up the rail and went to MLOK. There is a Midwest MLOK rail available for the Legacy.
6. Sig went to the tapped lug bolt in order to meet the 20,000 rounds without a need for parts replacements. Which if that's the only change that affected reliability Sig needed to do to get there then it goes to show you how inherently reliable of a design that the MCX is and that the Legacy was incredibly reliable as well.
7. They went to metal spring cup retention plate instead of plastic. This is the same plate that failed on Nutnfancy who admittedly ran his MCX on standard AR lower without the proper adapter during the majority of his testing. Doing so leaves the springs cup retention plate only partially supported and is indeed running the rifle in a way that is against manufacturer recommendations and the way it was intended. To his credit in a later follow up video of the MCX Nutnfancy acknowledged veiwer concerns of this and admitted that he might have caused the failure. None the less Sig redesigned and improved this part which is backwards compatible with a Legacy MCX and be ordered from Sig. The new retention plate is pinned in you'll have to remove it by punching out the pin.
8. The Virtus comes with a telescopic stock. Personally I liked the skeleton stock because weight most people report liking the new stock better however if you have a skeleton stock you dont like they are selling for $300 on Gunbroker right now they are discontinued and it seems people want them.
All in all for someone that does not run 300BLK those improvements are marginal IMO. The Legacy's trigger, stock and rail can be upgraded and it's a lighter platform however the Virtus comes that way is a bit more accurate and is rated for 20,000 rounds. Personally I prefer the lighter Legacy the gun is very well balanced and it handles very very well and mine is pre recall as I don't shoot 300BLK and I like having the ability to have AR15 bolt compatibility as one day parts may get hard to find especially for a proprietary gun but I already have spare AR15 bolts.
