LMT MARS-L Slip Fit Magwell (SFM™)

Now for the prevalent MARS-L lowers from LMT, we bring you our Slip Fit Magwell (SFM™)

Our tried and true attachment method, co-developed with Darq Industries, embraces simplicity, allowing our magwells to be comprised of only three pieces – the polymer “funnel”/magwell itself, one 4-40 socket head screw, and one threaded insert. This package offers a secure and reliable fit, while also keeping the overall weight right at .55 oz, making it nearly invisible on your weapon system until you utilize the 150%+ increased funnel size – all function, no fluff.

*only compatible with LMT MARS-L lower receivers. For Aero M4E1/BA Enhanced, please use this variant. For standard forged models, please use this one. For Radian ADAC, please use this one, and for ADM UIC/ADM4, please use this one. If you have any trouble when installing your SFM™ please contact us for assistance.

Please Note:

1 – We’ve seen increasing variance in LMT lower receiver machining over the past few years. While the vast majority of tested units fit cleanly, some newer serial numbers may show a slight internal lip at the funnel, usually only on one side. This has zero impact on function and is purely cosmetic.

Rather than compromising fit on well-machined lowers by overcompensating for outliers, we designed this part to strike the best overall balance—prioritizing clean lines, secure fitment, and reliable performance across the widest range of LMT receivers. If you have any questions, please contact us for assistance.

2 – Due to the efficient attachment method, minimal torque is needed when tightening the screw. Simply tighten the screw until the split section begins to touch, then just shy of a 1/2 turn of the screw for final torquing.