A match made in hell.


Well maybe not hell, but it just doesn’t work.

Sometimes you see people who think that buying the best individual components and slapping them all together will result in the best results.  Sometimes that just doesn’t work.

For example, the rifle in this picture does not function.

The lower is a LMT MARS-LS, which some say is the best ambi lower on the market.  The upper is a Larue Ultimate Upper.

It doesn’t work because the UU upper has some additional material by the brass defector/ejection port.  That material pushes the right side bolt catch out causing the bolt catch to mash into the bolt carrier preventing it from moving.

This upper, and this lower are awesome on their own.  But together they are a non functional mess.

I’ll do a proper review of the MARS-LS after I have some trigger time on it.  But it won’t be with the upper in the picture.


      • Yup, in this case both companies products deviate from the standard (in good ways) but because of that they do not work together. It isn’t a QA or tolerance stacking issue in this case.


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