The Guns & Ammo Network

S&W Chambers .300 Whisper

by J. Scott Rupp • November 2, 2011 • 3 comments
Smith & Wesson M&P15 in .300 Whisper

The Smith & Wesson M&P15 is now available in .300 Whisper, the first production rifle so chambered.

Smith & Wesson is adding the .300 Whisper chambering to its M&P15 lineup. It’s the first production AR-15 to chamber the cartridge. It has a 16-inch Melonite finished chrome-moly barrel with 1:7.5 twist and 5R rifling (the latter a contribution from the designers at Thompson/Center, who have been using 5R for years; T/C is owned by S&W). The twist rate is designed to accommodate the very light/very heavy bullets employed in the .300 Whisper—more on that in a minute—and the barrel is threaded 5/8-24 for a suppressor and comes with an A2-style flash hider. The gas key and bolt carrier are chrome-lined.

Hornady .300 Whisper

The .300 Whisper is available from Hornady in two versions: heavy-bullet subsonic, and light-bullet moderate velocity.

The upper and lower receivers are forged 7075 aluminum and coated with Realtree APG finish. It’s optics ready, courtesy of a Picatinny-style rail on the upper. The rifle sports a single-stage trigger, integral one-piece trigger guard, dust cover, forward assist and six-position collapsible CAR stock. It ships with a 10-round magazine.

The M&P15 300 Whisper will also be available with a black tactical upper featuring a 10-inch free-float quad rail and a Yankee Hill Phantom flash hider. The upper is compatible with any mil-spec AR lower.

If you’re not familiar with the .300 Whisper, the cartridge was designed by JD Jones of SSK Industriesand is currently a

factory round from Hornady. It’s based on the .221 Remington case necked up to .308. The round was designed to meet two criteria: be compatible with the AR-15 platform, Contenders and bolt-action rifles; and be easily suppressed.

The low-recoiling .300 Whisper comes in two flavors: subsonic, heavy-for-caliber bullets; and moderate velocity with light-for-caliber bullets. Hornady’s loads include a 208-grain A-Max at 1,020 fps muzzle velocity, with a muzzle energy of 480 ft.-lbs., out of a 16-inch test barrel. At 100 yards it’s doing 993 fps and 455 ft.-lbs. and at 200 it’s generating 968 fps and 433 ft.-lbs.

Hornady’s light-for-caliber offering is a 110-grain V-Max that produces 2,375 fps at the muzzle for 1,377 ft.-lbs. of energy (16-inch test barrel). At 100 yards it’s going 2,094 fps (1,071 ft.-lbs.), and it’s still running 1,833 fps for 820 ft.-lbs. at 200.

In Ammo, Ballistics • Tagged , , , , , , ,
  • Lopaka Kanaka

    The bullet looks like a hand guns ammunition? Short but a 308 size 208g or a 110g bullet with lots of fps at a 100 yards. The 300 whisper is a untested ammuntion for hunting? All NRA Life Members, Hunters, and Target Buffs, Keep doing what you do best, good hunting and shooting. We need to protect "Our Rights to Bear Arms" We need a new commander in chief who will protect Our Rights To Bear Arms so every Amercan Citizen can have GUNS in his home to protect his family and have a CCW. Vote to protect your GUN rights!

  • Joseph H

    I was really disappointed in my S&W M&P 15 in Whisper/Blackout. Couple of failures to feed, and a couple to eject. Plus the trigger broke during my first range session. I believe the chamber was a little too tight on mine, causing some of the ejection issues and probably some of the feeding issues as well. After about a 120 rounds the trigger just stopped working. S&W should rethink how they package this rifle. I know it's main use is 200 yards or shorter, but it would be nice to have a free float tube and to lose that huge front sight/gas block/sling mount. Maybe it's not meant to be a tack drive, bur for a $1000 gun, that handguard, gas block/sling mount sure aren't helping any thing. Hope it's better when it gets back from S&W. Two weeks and no word.

  • cam miller

    I have a friend that has a300accblackout he thinks it great. iam not sold.yes its easy to put a can on it but it has no down range horsepower you couldnt get from a large cal pistol. I would rather carry a 460 s/w.In short for the power a gun in a holster is hard to beat.