The Mac 5, Affordable MP5 Clone allowing ability to Upgrade.

 The Mac 5, Poor Man's MP5. First upgrade is to add a rail and M-LOC forgrip system from UTG PRO. This was made to modernize the MP5 and other clones. 

I received the Mac 5 with an SB Tactical pistol brace, 4 mags, flash hider, cleaning kit, sling, and hard case. It was a great deal for around 1200.00. The huge savings allowed me to upgrade and accessorize. Had I bought the HK equivalent, it would be around 3K for the exact same gun. This takes all the HK Parts. Yes, it's a clone, but a damn good one. This is one of those wishlist guns I've always wanted. Great truck or home defence gun. 

 

Start by removing the current forgrip. Using a plastic punch and a small hammer I tap out the retaining pin.

Next, if the bolt is forward, you will want to cock it back and lock it to the rear. This will be required to slide the rail over the cocking knob.

Once locked back to the rear, you can slide the rail into position.

With the gun turned sideways, you can insert the little round nut. Pay attention to the engraved arrows for proper orientation.

Once dropped in, you will notice additional line engraving on the face of the circular nut as well as on the rail and foregrip upper piece. These locks are designed to use the built-in scope mounting locations.

The lines are there to help you properly orient the nuts, so the screws can line up with the threaded holes. 

Now, I use blue Locktite on all screws. For now, get all mounting started and apply Locktite to all screws to ensure nothing will back out. 

When aligning be sure the upper falls into the groove that are milled out. 

Be careful with the lower; it does have a direction it needs to be installed in. The front section must be flush with the upper piece, and if it's not, you have it backward. 

The torque spec for all the screws is 20 in-lbs

Reinstall the optional flash hider if you like. In the future, this will be replaced by another suppressor. 

The completed upgrade is pictured below. Not only are the ergonomics better with this upgrade, but it will allow for many accessory options from laser sight, to lights, to red/green dot, or even a low variable optic.