Rifle Kit, 16" M4, gas block, A3






AR15 / M16 A3 Complete Parts kit LESS lower receiver, with 16" inch M4 contour barrel and A3 Upper receiver. Item # AR-RKM4A3.

M4 Feed Ramp barrel extension
T-Marked forged upper receiver
1-9" twist, 6 grooves, right hand
5.56mm chamber (shoot either 5.56mm or .223)
11595E Barrel steel
Manganese Phosphate finish barrel

This 5.56mm caliber barrel is 16" long, threaded the standard 1/2 x 28 tpi, and has an A2 flash hider with the correct crush washer. The barrel has a four position gas block instead of the standard front sight base which can interfere with optics.  This gas block has picatinny rails on all four sides and it is USER adjustable for windage (simply loosen the screws, adjust for windage, and re-tighten.  It sports M4 contour and length cool tunnel handguards, and a correctly sized gas port for reliable function. The barrel is machined from chrome-moly, high vanadium steel and hardened to a U.S. government Mil-spec of Rc 26-32. The barrel, and all external steel parts, are manganese phosphate finished IAW of Mil-STD-171, the U. S. government's recommended protective finish for steel. This finish not only looks great, it affords complete corrosion protection. These barrels are of Mil-spec M4 contour (.750 under the front sight base) complete with the M203 groove in the front. This contour is the perfect balance between light weight, heat dissipation, and accuracy.

The barrel is mounted on a FORGED A3 upper receiver with built in Mil-spec M1913 Picatinny accessory rail, with the correct rail numbers engraved, made from certified forgings, hardcoat anodized IAW Mil Spec A8625, Type III, Class II, black per No. 37038, Table IX with nickel acetate seal, as per the Mil-spec. The upper features a forward assist and hinged ejection port cover.

The buttstock tube is the mil spec thickness (1.145" OD) M4 buttstock (not the cheaper carbine buttstock). This buttstock features 6 positions for maximum shooter comfort, reinforced honeycomb design for heavy duty use.

All semi auto lower receiver parts are INCLUDED as well as semi auto bolt, carrier, and charging handle. The upper is COMPLETELY ASSEMBLED. Each and every part to the gun is included EXCEPT the stripped lower receiver! (A complete firearm is pictured, the lower receiver and magazine, even though shown in the picture, are NOT included)  


PLEASE NOTE:  For CHROMED barrel interior and chamber, You must ACTUALLY Order part # AR-CHROME on your web order form, if you do not see it and it does not charge you $50 on your form, you have not ordered it and will not receive a chromed barrel. Do NOT just put it in the special instructions.  Here is the link: http://blackthorneproducts.com/cart/index.php?main_page=product_info&cPath=0&products_id=300

Since this parts kit does not include the receiver, no FFL is required. Like all of our AR parts kits, this is MADE IN USA!

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  • Model: AR-RK16M4A3block
  • 47 Units in Stock

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This product was added to our catalog on Wednesday 19 October, 2011.