What do you want to know? I was holding one yesterday at the gunshop. I'm still stewing as to whether to get it or not. Check my post for some other info.
I've found a couple other things on it. It seems that Beretta and Sig were colaborating on a rifle, then dropped the project. They both developed their rifles separately, and resulted in the strong resemblence of the AR-70 to the Sig 550. They are not the same gun though, and in no way should be confused with being so.
Here's what I've figured out:
There is a detachable 22mm (NATO STD) flash suppressor that allows firing of rifle grenades. The quick detach feature allows the use of BFAs, suppressors, etc without having to get out the wrench (where you'd find such an attatchment and what it would cost would be a search unto itself). There is a gas block located on the top of the barrel. There is no gas adjustment, just an "on-off" switch for grenade firing. It uses a normal piston arangement with a return spring. The bolt carrier is a square block that holds the bolt, which is a two lug deal, pretty much like an M-1 or AK. The operating handle is a separate piece, the same as an AR-180 or Daewoo. Obviously you can push forward on it as well as pushing back. The handguard is a removeable, one piece plastic unit.
The upper receiver is stamped and rectangular in shape. There is a take-down pin at the rear and a pivot pin at the front, similar to an AR-15. The rear pin is just pushed out, but the front pin is not easily removed. It's held in place by a splitring that would require special pliers to remove. Evidently they figured just "shotgunning" the weapon was enough for troop level maintenance. The front sight is a post, adjustable for elevation. The rear sight is a 150/300M flip, adjustable for windage.
The lower is stamped as well. The bolt holds open on the last round, and there is a release similar to the M-16, in a similar position. The internals were conventional, and similar in function to the AR, which is similar to plenty of other rifles as well. The pistol grip was VERY comfortable. It was just the right size, shape and angle. There is a removeable plate on the bottom of the pistol grip to form a storage compartment, and the little door is used as a tool to adjust windage. The buttstock was plastic as well. It was very lightweight, and thin-walled. There was a slot cut in the side, I assume for the sling. The buttplate was just a recoil pad. The example I saw had black electrical tape around the mating area of the buttstock and pad. I don't know if they're removeable and this one is now too removeable, or if they are trying to disguise a fault. I didn't bother to actually take the tape off to find out unless I become serious about buying it.
The 30rd mag is described in detail in my post on the rifle. It was very postitive in locking and unlocking. No abnormal movements were needed. It was very easy to use. Not as fast as the button release of the AR-15, but far more secure.
Technical specs you can get at the websites already mentioned.
Ross