Armory Dynamics Stainless Spring Loaded Receiver Tension Screw replaces the standard Nylon Tip Screw. This is an upgrade feature that allows easier and quicker breakdown of the receivers.
Approximately 6-12 pounds of spring loaded force between upper and lower receiver. The tighter the screw is set the more force of the spring.
With a standard set screw you have to set the tension with the grip off and then remove the grip to adjust tension if it is needed later. With the spring loaded set screw you set it once and forget it..
Once installed though the bottom and the grip is in place, you can actually set it set the tension from the top and not have to remove the grip.
Requires a small flat blade screwdriver to install.