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Smith & Wesson M&P 15 Upper Assembly .300 Whisper 16 Inch Threaded Barrel 5R Rifling Quad Rail Flash Suppressor 812012S

Smith & Wesson M&P 15 Upper Assembly .300 Whisper 16 Inch Threaded Barrel 5R Rifling Quad Rail Flash Suppressor
Smith & Wesson M&P 15 Upper Assembly .300 Whisper 16 Inch Threaded Barrel 5R Rifling Quad Rail Flash Suppressor
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Smith & Wesson M&P 15 Upper Assembly .300 Whisper 16 Inch Threaded Barrel 5R Rifling Quad Rail Flash Suppressor

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Questions & Answers
Will this fit on a Bushmaster AR-15 5.56 lower? Expert Answer

Yes. The Smith & Wesson M&P 15 Upper Assembly is compatible with a Bushmaster AR-15 lower receiver.

by Ethan, Gear Expert, July 6, 2022
Is the upper suppressor ready or do I need to order a new barrel? Manufacturer Answer

The barrel on this upper is threaded with a 5/8-24 thread pitch. A suppressor can be directly mounted to the barrel.

by Smith and Wesson, Manufacturer, January 21, 2021
View All Q&A You Have a Question? Ask!
Customer Reviews
Helpful Positive Review
M&P 15 300 blackout/whisper by Bill, March 17, 2016
Excellent quality and functionality. Reliable subsonic functionality. 300 blackout/300 Whisper marked on the barrel. 200 characters is required but I think I said it all in the first three sentences.
4/6 found this helpful
Helpful Positive Review
S&W 300 Blackout Upper by Chuck, Verified Owner, February 28, 2016
Initially bought this upper to swap out with the 5.56 on my S&W MP15. I wanted the gun to match regardless if using 300 or 5.56. I probably could have done it cheaper with pieces and parts but I like the look of my 5.56 S&W so I went for this 300 B...
Read More...
7/7 found this helpful
Read All 2 Reviews

Product Discontinued by Manufacturer

Smith & Wesson M&P 15 Upper Assembly .300 Whisper 16 Inch Threaded Barrel 5R Rifling Quad Rail Flash Suppressor 812012S has been discontinued by Smith & Wesson and is no longer available. Our product experts have helped us select these available replacements below.You can also explore other items in the Gun Parts, AR 15 Parts, Rifle Parts, AR15 Upper Receivers yourself to try and find the perfect replacement for you!

ATTENTION! We currently do not ship this product to P.O. Boxes, AK, CA, CT, DE, HI, MA, NJ, NY, U.S. Territories, or select Colorado locations. Please see our policies for more information or a detailed list of locations.

Product Info for Smith & Wesson M&P 15 Upper Assembly .300 Whisper 16 Inch Threaded Barrel 5R Rifling Quad Rail Flash Suppressor 812012S

Manufactured on the M&P15 modern sporting rifle platform Chambered in .300 Whisper Will also safely fire .300 AAC Blackout Very effective short range round (approx. 200 yards) for hunting deer-sized game Tactical application for the cartridge is for short-range target shooting Cartridge has a very low recoil and muzzle blast Designed to operate with or without sound suppressor Barrel threaded to 5/8-2. Feed ramps and gas system optimized to run efficiently with a full range of factory loaded sub-sonic and super-sonic ammunition both suppressed and unsuppressed Barrel twist rate (1 in 7.5?) is compatible with a wide variety of bullet weights from 110 to 220+ grains.image

Package Contents:

  • Smith & Wesson M&P 15 Upper Assembly .300 Whisper 16 Inch Threaded Barrel 5R Rifling Quad Rail Flash Suppressor 812012S

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Smith & Wesson M&P 15 Upper Assembly .300 Whisper 16 Inch Threaded Barrel 5R Rifling Quad Rail Flash Suppressor 812012S Unavailable & Discontinued Models

List of Unorderable Models

  • Smith & Wesson M&P 15 Upper Assembly .300 Whisper 16 Inch Threaded Barrel 5R Rifling Quad Rail Flash Suppressor , MPN: 812012S , UPC: 022188147773 , Code: SN-UFH-812012S
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Last updated 2026-11-04 UTC.