We have some preliminary overhead piston designs that may eventually get released, after we get some of the more important work done.
We have alot of magwells and other items relating to our MGI Modular Weapon System to complete right now, and a piston operating system is sort of on the back burner.

If/when we release an overhead gas piston design for our MGI QCB, it will be able to easily allow the quick-change-barrel capabilities of our QCB, and not slow down the process of changing barrels, and will be easy for the user to work with in this role.

An overhead gas piston system is not "rocket science" and Mack has designed a number of guns 30 years ago which had piston gas systems, so it is not a big job for him to come up with one now.

There is a reason that no gas piston systems have replaced the direct impingement system on the AR15 for almost 50 years, even though many have been tried, and still trying. Some might say that it is because the direct impingement system that was designed into the AR15 is the best one for this job. Stoner knew all about piston systems, buy yet he decided to use direct impingement in this weapon, and he had reasons.

Piston systems will work in the AR15, as has been proven many times.
Whether they are actually an improvement, remains yet to be proven after 50 years of trying.
Some say they have "proven it" with their current piston offerings.
Time will tell.
I'd say that when you shorten the barrel so far that the direct impingement system starts to have trouble operating, then there is some argument for an overhead piston to be used.

If market demand is there for a piston operating system in our MGI Modular System, then we will provide a very good one for those who want it.

From my point of view as a marketer, I would personally rather ask the customer, "Piston system or Direct Impingment system on your MGI QCB order, sir?", than  spending an hour arguing the merits of one system agains the other.

Quoted: WHEN WILL THE NEW RECEIVERS BE AVAILABLE?   CAN THE NOVESKE BARRELS BE USED IN THIS RECEIVER?

From the most recent reports that I've had about the production status, the new Modular Lower Receivers should be done in about 3 weeks, and the new QCB Upper Receivers are scheduled for the end of March.

Yes, Noveske barrels can be used in them.

Quoted: Quoted: Stoner knew all about piston systems, buy yet he decided to use direct impingement in this weapon, and he had reasons. My theory is that he was trying to save as much weight as possible vs the M14. It is interesting to note that everything he did afterwards (AR180, Stoner 63) was piston driven.

It is my understanding that since the patent for the DI was sold to Colt with the AR15, that Stoner or Armalite had to use more conventional piston operating systems after Colt bought the AR15 and the patent rights.
Yes, the DI is lighter, and also resolves all the forces of firing and cycling in one single line of force in axis with the boreline. No piston system has ever done this before, or since.

Quoted: Quoted: . . .  the new Modular Lower Receivers should be done in about 3 weeks . . . Any word yet on pricing and general availability?

THe price for the MGI Modular Lwer receiver with AR15 magwell included, in "complete lower" form, with collapsible 6-position buttstock, pistol grip and complete LPK is $599.95.

The delay at CMT in getting these items started for the 2nd production run has now been hurdled, and they have been started. Can't estimate an exact time right now, but I think they will be within that 3 week time frame.

We are taking back-orders on the lowers, and won't charge the card until the unit ships.
You can just call me or email me to get on the list.
The 2nd run is almost halfway sold-out already from back-orders already placed.