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:

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.