Hello, I want to run Magpul furniture on my Sporter II. Should I order their 'Commercial' or 'Mil Spec.' stock, handguard and grip?
Cheers, Bill

It depends which model you have.. my CA compliant version had commerical sized buffer tube, but most normal versions use mil-spec. Best to measure yourself. I prefer mil-spec on all my ARs, so I just spent extra $25 and changed out the buffer tube.

Measure your buffer tube. My former employer bought a slew of M&P15s back around 2003-2004 and they came with commercial extensions/tubes. After comparing commercial and actual Colt examples rather than theoretical blueprint specs, and metal characteristics, we decided there wasn't any reason to worry about the source. In fact, looking at metal specs, the commercial tubes actually had a higher shear strength.

FWIW, the nominal diameter of a commercial carbine buffer tube is 1.170 in. The diameter of the mil spec carbine tube is 1.140 in at the area of the stock. If you have a mil spec tube, you'll see it reduce outside diameter a short distance behind the tube nut/threads.

SFAIK, the grips are the same-but you might find a different contour grip a big help. Dunno why there'd be a difference in handguards. I didn't see a choice in their catalog ten years ago.

My Sport II wears the mil-spec Magpul fixed carbine stock. Fit is snug enough that the commercial one won't go on. As to handguard and grip, just go with the one you like the best and is comfortable.

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Peace was my Profession

Mill spec, that's what I use.