Smith & Wesson M&P15 in 300 Whisper, 300 BLACKOUT

Smith & Wesson M&P15 300 Whisper

The new S&W M&P15 rifle comes chambered in 300 Whisper and will also chamber 300 BLACKOUT cartridge.

Smith & Wesson announced a new M&P15 rifle chambered in 300 Whisper.  The S&W rifle will also chamber the popular new 300 BLACKOUT cartridge.

Two versions of the new M&P rifle will be available: one with a Realtree APG finish (shown here) and one with a black finish.  The Realtree version of the M&P15 will feature a 5/8-24 threaded barrel along with an A2-style flash hider, while the black version of the rifle will use a Yankee Hill flash hider.  Both rifles will have a 16″ barrel.

The black version of the 300 Whisper rifle will have a free floating, 10″ quad rail for accessory attachments.  Both rifles are “optic ready” with a Picatinny rail for the addition of traditional or electronic sights.

Both the 300 Whisper and the 300 BLACKOUT cartridges are design to work well with suppressors.  According to Smith & Wesson, “The feed ramps and gas system have been optimized to run effectively with a full-range of factory loaded sub-sonic and supersonic ammunition, both suppressed and unsuppressed. The barrel’s twist rate is compatible with a wide variety of bullet weights from 110 to 220+ grains.”

Smith & Wesson M&P15 300 Whisper

caliber.300 Whisper/.300 AAC Blackout
standard magazine capacity10 rounds
barrel length16"
twist rate1:7.5"
overall length32" - 35"
weight (unloaded)6.38 pounds
receiver material7075 T6 aluminium
barrel material4140 steel
finishRealtree APG

Smith & Wesson M&P15

Smith & Wesson M&P15 300 Whisper Rifle


The black version of the rifle is no longer offered by Smith & Wesson.  The camo (hunting) version of the rifle is still available from the company.

For a time, S&W offered uppers chambered for the .300 Whisper cartridge, but right now it does not appear the company is selling them.  A single reference on the company website states that the uppers are “out of stock” and lists a MSRP of $819.  The upper pictured matches the uppers that used to be sold on the non-camo version of the rifle (black and using the Yankee Hill flash suppressor.)

Here is the current Smith & Wesson literature on the .300 Whisper upper:

SureFire X300 WeaponLight

surefire x300Trust the brand that has been combat tested by US Special Forces and elite law enforcement units the world over. The X300 WeaponLight is battle hardened and ready for duty on your pistol, rifle or shotgun.

500 lumens and instant on activation will give you the decisive advantage if you are faced with a lethal force encounter.  Accept only the best - your life is worth it.
About Richard Johnson

Richard Johnson is a gun writer, police trainer and really bad joke teller. Check out his other writing in Combat Handguns, Guns & Weapons for Law Enforcement, on The Firearm Blog and at BlueSheepdog.