Left Hand Complete AR15 Upper Receiver- 17-5.56, 18" Barrel, 15" Mlok

Upper

• Barrel Length-18”
• Barrel Material- 416 R Stainless, Blasted Matte Grey
• Chamber 17-556 KAK
• Twist Rate 1:9
• Muzzle Device- KAK SAW Flash Hider 
• Extension- M4
• Gas System- Magnum Length
• Gas Block- Low profile .750 phosphate Finish
• Upper Receiver- Billet Aluminum, High Quality, Precision Machined to M16/M4 Spec, Slick Side Configuration
• Handguard- 15” Mlok, High Quality 6061 T6 Material Mlok with Proprietary Clamping System and Heavy-Duty Barrel Nut
•  Charging Handle- Milspec with Enhanced Large Billet Latch

BCG 

• M16 Auto Profile Carrier Machined from Aircraft/ Bearing Quality 8620 Steel, Properly Heat Treated, Ground to Perfection
• Bolt is machined from a single piece aircraft/bearing quality 9310 steel, heat treated properly, precision ground, Shot Peened and MPI’d
• Firing pin is machined to the mil-spec print from 8740, precision ground, and chrome plated
• One Piece Billet Fully Machined Enhanced Extractor, Phosphate coated for Increased reliability and corrosion resistance
• S7 tool steel ejector and extractor retaining pin
• 4130 Gas Key, precision staked using our hydraulic staking machine
• KAK Carrier Key Screws- T25 drive, Grade 8, Properly Heat Treated

All KAK complete upper receivers are test fired for feed and function using commercially loaded ammunition

NOTICE- 17-556 Was created by KAK Industry and is our proprietary chamber design. This chambering is NOT cross compatible with similar cartridges, do not attempt using other rounds in the 17-556 chamber.

We wanted to use brass that was plentiful and inexpensive, like lake city 5.56 military brass. We developed sub .5" loads or better with powder ranging from 4198- Ramshot Tac in correlation to the burn range data. Base loads can be worked up from 17-223 and 17 Remington load data for a base load. While using 20 gr bullets, and even faster with 15.5 gr. Velocities from 4200- Exceeding 4600+ FPS fps depending on charge and bullet weight is what we found to be optimal with this barrel.

We are producing KAK Industry 17-556 Custom chambered barrels for this cartridge currently.

Our Custom Chamber Reamers offer improvements such as reliable extraction, no neck turning needed, and the correct amount free bore in correlation to these light varmint bullets liking a jump to be accurate.

The barrels have optimized tweaks to aid in reliable extraction.

We worked with Redding to produce dies that match our chambers perfectly.

NOTICE- 17-556 Was created by KAK Industry and is our proprietary chamber design. This chambering is NOT cross compatible with similar cartridges, do not attempt using other rounds in the 17-556 chamber.

This chamber is NOT compatible with 17 Remington

DOWNLOAD 17-556 RELOADING DATA

"What's make this different from 17 Remington?"

The only commonality between 17 rem and 17-5.56 is that they shoot the same caliber bullet.

17-5.56 is 17 Remington on steroids, you can expect velocity gain at 100 ft/s per inch of barrel.

• 17-5.56 has 30% more case capacity compared to 17 Rem.
• Cheap 5.56/ 223 brass can be converted opposed to 17 rem brass being $1/ each (if you can find it).
• Our reamer/ chamber design has eliminated to notorious 17 cal bore fouling issue which requires frequent bore maintenance. 17-5.56 was designed to run clean or very dirty without compromising precision which eliminates the often talked about “17 cal flier” folks have experienced with 17 rem, 17 hmr, etc.
• 17-5.56 load data start loads are often 17 rem middle/max loads.
• 17-5.56 achieves higher velocity compared to 17 rem while utilizing a shorter barrel.

"How Long will my barrel last" is a question we get a lot, the fact of the matter is that we don't know as we have not been able to burn out a barrel, even with it's heavy firing schedules. Take our original prototype barrel which has been used internally for over a year now. It is well abused and used, more than 2000 rounds through it, all screamers, along with full auto use,  not to mention we did all of or pressure testing data with this barrel which far exceeds recommended load data. This barrel still shoots TINY groups. There are hundreds of these barrels on the market, no one has "burned out a barrel"