Glad you like it.

We finish the forend after rail mounting, to ensure that the rails mount flat against the even surface of the tube. I have used barbecue black high-heat paint on my forend for touch-ups, and that works out pretty good, and it is quick and easy.
The finish applied to the fore-end is actually a powder-coat, which should hold up better than a simple spray paint in that application.

Regarding the relief-cuts inside the upper receiver for using it with AK mags, it has been tested with higher-recoiling calibers than the 223 with no ill-effects seen.

It looks really cool!
Very nice clear pics, too!

Quoted: Quoted: It looks really cool! Very nice clear pics, too! This might not be your forte', but how 'bout some take down pins  with a split ring in them to make it easier to pull them out and disassemble the gun?   No more stressing the finger nails or looking for a punch.  The perfect accessory for those who like to tear it down alot.....yea. Why did you guys go with a powdercoat instead of anodization?  It is pretty thick and makes it tough to crank down an ARMS mount.  My vfg's mount has already taken the paint off of where it mounts just from being attached.

I think that the improved take-down pins are a good idea.
I've already mentioned that to Mack a while back, because I feel the same way you do.
He's too busy right now, but we may get around to something like that.

As for the powder coating, it is strictly a cost saving process that helped us to keep the price of the QCB unit in the affordable range. We could have done a fancy railed fore-end, but we didn't want to have to price the unit at $1000. We wanted to make it so that as many folks as possible could afford it.

At this time, the relief cuts are done after anodizing, and they are not re-anodized after cutting.
In the future, when we have the new forging dies made, they will be finished with anodizing on these cuts.
These are not areas which have any wear, and anodizing would only provide additional corrosion protection anyway.
It is an evolutionary process that is being undertaken. We have additional things we are incorporating in this new forging die we are having made, and these will all appear in a future upgrade at a later date.
I know that we'd all like to have everything done in one process, but we cannot do it all at once, and we are making the product available to people while we are still in the evolutionary process.

Zissou,
Here are the photos that I have of the operational area of the locking block for the MGI QCB upper receiver unit.
This unit shown in the photos is a very early model when they first came out 2 years ago. There are several changes that have been made to clean up the appearance of the system over the years, but this illustrates the basic design and operation of it.

First, this is a photo showing the levers opened up halfway. They must be rotated fully out toward the sides(90 degrees from the barrel axis) to allow barrel insertion/withdrawl.



Next, is a photo shwing the system with the levers closed, and held captive by the spring loaded capture plungers. This is how the levers are positioned when a barrel is inserted, holding the barrel in place.



I have no photos of the unit disassembled at this time.
It is a simple rotating-cam arrangement, which has sections of the lever-operated cams that hold the barrel in tight against the barrel extension flange when closed, and rotate open to allow room for the barrel to be removed/inserted when opened. It is all steel, except for the handguard components, which are aluminum. Weight of the entire upper receiver unit with handguards and rail system all toghether is approximately 26 ounces in the current form.
The unit is field-strippable by the user, for cleaning or maintenance, should that become necessary.
Simple tensioning techniques on the levers allow for adjustments and take-up for any wear over time.
The entire system is very strong, robust in design and materials.
Over 2 years of use in the marketplace is showing very good record for the design overall.
Regular AR15 barrels are used, so you can use any of your existing barrels, or any typical AR15 barrel, as long as the barrel nut, delta ring, and handguard keeper are removed, much like most other free-float tube systems.

Barrel changes are very quick and easy, in the field by the user with no tools required.
Probably about 15-30 second time of barrel change, once you get used to using it.
Our system is what we feel is best for returning to zero, because there are no screw-torques to worry about changing the POI if different torque is applied.
In our system, barrel holding pressure is always consistent when returning barrels into the system, because of the simple cam tension principle.
This was designed by Mack Gwinn, who designed the quick-change barrel system for the current model of FN-M2-HBQCB 50cal heavy machine gun in use all over the world today. He is an expert in quick-change barrel systems, and it shows with this simple but very effective design for the AR15. In fact, it is the simplicity of the design that provides the strong points of the system, and also its robust and long lasting qualites, as well as the great overall performance characteristics.
It is the most affordable quick-change barrel system for the AR15 that is available today, by far.
We feel that it is also the very best performing system at any price, and certainly the fastest.

Mack strives for functional simplicity in his designs.
In fact, as Yekimak mentions, it is almost  deceptively simple.
The fact that he could include all the benefits that are in this system into such a few parts is very commendable.
Even I, as an assistant designer, am continually amazed to see the total functionality of this system.
Especially, the fact that this type of locking of the barrel extension with the cams provides a better lockup with virtually perfect consistency in barrel pressure, that is essentially passive to the user. He just closes the levers, and the exact correct pressure on both sides of the barrel is automatically performed, without any attention to screws or wrenches or torque-settings, and they cannot back-out under use like screws can. They are alot faster than screws. They cannot strip out or get lost like screws can.
It is really an amazing piece of design work, which is so simple-looking that it would be easy for a non-designer to totally overlook just how comprehensively well-designed this basic cam system is. It's not until you try to sit down and design any improvements into it, that you find out how close to functionally-perfect this idea is. I have tried that, and Mack is a pretty tough act to follow.

When you are a designer, you soon learn that there is no such thing as perfect. Any design can be "nit-picked", no matter how good it is. The success of a design will relate to how well it performs, and how few compromises it makes, at the price point target. Ultimately, it is the consumers who will decide how well we did.

We know what people have said that needs improvements for better market acceptance, and we are moving in that direction with some upgrades as we go along. At the same time, we are making products that give even more versatility to the QCB, by adding the  modular lower for different magazines, and working on barrel packages for other calibers. We have a "high reliabillity" action-parts line coming along, which will help to deal with sand and dust like the military is encountering in Iraq.  We have several select-fire fire control groups coming up. We have plans for a piston-operated system option too, for those who want to go that way. We have belt-feed under development.

We are some very busy folks right now.

Our MGI QCB uppers are all coming now with true M4 feedramps in them.

In standard rifle barrel extensions, there will be an overhang over the M4 ramps, which could present a feed problem in certain guns.

Generally, in most guns, it does not present a problem, because the cartridge should feed directly into the barrel extension, and not contact the upper receiver walls at all.
If the mag feed lips are bent down at all, or if the mag catch is loose, or if there are overcycling issues, causing the ammo to be at the wrong feed angle during cycling, this problem can occur.

The barrel extension should be perfectly aligned with the front wall of the receiver.
If this is not the case, please contact me about it.

Thanks,
Tom

Sounds like you have everything under control now.
I'm happy that were were skilled enough to handle the issue.

Timantaor,
The newer systems have updated lever assemblies, and no longer look like those older photos that I've posted.
The levers now go thru the cam shafts.
We no longer weld the levers to the bottom of the cam shafts, like the older units were.

Here is a shot of the newer lever arrangement, that is lifted from another thread, of LArifleMAN's MGI upper with a 357 Sig setup.

I know, that welding bugged some people, so  we changed it a while back.
I still have my original QCB unit, which was one of the first ones that ever came out, and it has the welded levers on it.
Still working like a champ.
While my unit may look a bit like a prototype, it still has the same functionality, and there's nothing from anywhere else that can match it for performance.
Even after more than 2 years on the market, it still stands at the top of the list in quick-change barrel systems for the AR15.
It is the fastest, requires no tools, uses regular AR15 barrels, and provides the best accuracy and return-to-zero of anything out there.
It is still the lowest cost changeable barrel system for the AR15, too.

Oh, I've slowed down completely to a full-stop right here days ago.

I stop posting when it becomes clear that my input is not needed.

Quoted: I IM'd twl to apologize for the car salesman thing.   This is part of what I sent him: "I know the upper is a good product.  I think most everyone else does as well.  Your input on the technical aspects of your products is invaluable.  I got a little frustrated with the "it's the best" and "it's the only" stuff but it was out of line for me to chastise you in the forum that way." TWL, I am sorry for being a jerk.  I apologize for insulting you, and I apologize to everyone else whom may have lost out on some of your insight because of my comments.

Thanks Yekimak,
I appreciate your IM'ing me about it.
Sometimes I get a bit too excited about the products we make, because I use them and really do like them alot.
Maybe that sounds like a sales line, but it is how I really feel.
Anyway, no hard feelings, and I'll try to keep to the technical side of things on your thread.
Best regards,
Tom

Quoted: I wonder what kind of goodies Mack has for the M1A...

Mack isn't designing anything specifically for the M1A at this time.
However, we are friends with Sadlak, and we offer the Sadlak competition parts for the M1A.
Sadlak makes some of the finest M1A parts available.