Smith & Wesson M&P 15 Sport III 5.56 NATO
Model: 13807
Smith & Wesson M&P 15 Sport III 5.56 NATO
Model: 13807
Full Specifications
About This Firearm
The Sport III is Smith & Wesson's revision of the long-running M&P 15 Sport line, updating the Sport II with a free-floating M-LOK handguard and a faster 1:8 twist barrel. Those two changes address the Sport II's biggest limitations without fundamentally changing what made it popular. The 16-inch 4140 chrome-moly barrel keeps the same Armornite finish and the 7075-T6 receivers still get a hardcoat anodize treatment.
At 104.32 oz, the Sport III weighs roughly 1 oz more than its predecessor, a difference that disappears once you mount an optic. The M-LOK handguard accepts lights and accessories directly, eliminating the rail section adapters the Sport II required. Both the A2 front sight post and Magpul MBUS rear sight carry over, so the rifle still ships ready to shoot on irons.
If you already own a Sport II and it runs well, the Sport III does not offer enough to justify a swap. But for a new buyer choosing between the two, the 1:8 twist and M-LOK handguard make the Sport III the better starting point. It handles 77gr match ammunition that the Sport II's 1:9 twist cannot reliably stabilize, and the free-float rail improves accuracy potential for shooters who eventually add a magnified optic.
Best For
Strengths & Limitations
- The 1:8 twist rate handles 55gr through 77gr projectiles, giving it wider ammunition compatibility than the Sport II's 1:9 twist or the PA-15's faster 1:7 twist (which can over-spin lightweight varmint bullets)
- Free-floating M-LOK handguard accepts lights, grips, and bipods without rail adapters, matching mid-tier rifles like the IWI Zion-15 in attachment flexibility
- The mil-spec single-stage trigger has no published pull weight from Smith & Wesson, and community reports put it around 6-7 lbs, heavier than the Sig M400 Tread V2's factory two-stage Matchlite Duo
- Ships with only 1 magazine, same as every other budget AR in this group, though the Ruger Mini-14 includes 2
- No ambidextrous safety selector or bolt catch, limiting left-handed shooters compared to the Sig M400 Tread V2's ambidextrous controls
Category Rankings
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Frequently Asked Questions
What is the actual difference between the Sport II and Sport III?
Two things: the Sport III has a free-floating M-LOK handguard (the Sport II uses a drop-in Picatinny handguard) and a 1:8 twist barrel (the Sport II has a 1:9 twist). Everything else, including the Armornite-finished 4140 chrome-moly barrel, 7075-T6 receivers, and included sights, is the same. The weight difference is about 1 oz.
Does the Sport III need a break-in period?
Smith & Wesson does not specify a break-in procedure. Most owners on the M&P forums report running the first 200 rounds without any cleaning or issues. A light coat of oil on the bolt carrier group before the first range trip is standard practice for any new AR.