The Lancer Adaptive Magwell (LAM) is a bolt-on upgrade for all milspec AR-15's which increases the effective diameter of the magazine well, decreasing reload time and improving reliability under stressful or adverse conditions. Available in one-piece and two-piece configurations (see chart below for compatibility details) Designed for milspec AR-15 rifles and standard forged lower receivers with removable trigger guards Machined from 6061 T6 aluminum Includes rubber gaskets for a snug rattle-free fit Compatible with most standard M4/M16/AR15 pattern magazines NOTE: Lancer's Adaptive Magwell is not compatible with third generation (G3) Magpul PMAG's due to the magazine's over-travel stop The two-piece LAM is designed to fit S&W M&P models, along with some billet and non-standard lower receivers. It's rear tensioning screws allow for a greater range of adjustment. The two-piece LAM includes the hex key for tensioning the magwell during installation.COMPATIBILITYLower ReceiverOne-PieceTwo-PieceColtS&WXLMTDPMSStagOlympicBillet / Non-Standard ForgedX Select Models OnlyINSTALLATION INSTRUCTIONS (TWO-PIECE) Remove spring pin (or roll pin) from the front of the trigger guard where it connects the existing magwell. Swing the trigger guard down so that you have approximately 1/2 of clearance below the magwell. Using the supplied hex key, remove the (2) tensioning screws on the rear of the two-piece Lancer Adaptive Magwell (LAM) and separate the two halves. Slide the lower half of the LAM onto the lower lip of the receiver until it stops. Using a small screwdriver or the tip of a dummy round, depress the spring-loaded pin on the LAM and slide it the rest of the way onto the receiver until the spring-pin pops into place in the trigger guard pin hole. Re-install the front of the trigger guard into the mounting location on the LAM. Slide the upper half of the LAM onto the magwell and re-insert the tensioning screws. Tighten both screws evenly until the LAM is snug on the magwell. Do not over-tighten. Check to make sure the LAM is secure and perform a basic function test on the rifle prior to live-fire use.