SI Defense A2 billet upper receiver SI Defense
AR Upper Receivers

You have two options of AR-15 A3 upper receivers from SI Defense, uppers that are made from forgings and uppers that are made from billet.

Our A3 forged uppers are made from 7075 aluminum forgings and SI Defense forged A3 upper AR-15 receiverfeature a dust cover, shell deflector, forward assist and M4 feed ramps. The top rail is machined to MIL-1913 specifications. The upper is anodized per MIL-A-8625.

You have the option of getting your upper and lower receivers anodized in different colors: clear, flat dark earth, O.D. green, and desert sand.SI Defense FailZero forged A3 upper receiver

You can get an optional FailZero coating featuring EXO on your upper receiver as well. EXO Technology is a revolutionary surface technology that provides permanent dry lubricity, radically improves the performance of your AR-15 and eliminates the need to apply oil or grease to treated parts for the life of the weapon.

Our A2 billet uppers are made from a solid block of 7075 aluminum billet and feature a shell deflector, dust cover, removable picatinny side mount rail and M4 feed ramps. The top rail and removable side rail are machined to MIL-1913 specifications. The upper is anodized per MIL-A-8625. The side rail can be used to mount your light, laser or optic and re-distribute your weight of your rifle so that is is more balanced. The side mount picatinny rail has three 8-32 screws to mount it securely into place with a 3/32 allen wrench. The threaded holes in the upper receiver do not penetrate into the upper receiver bore, so you do not have to worry about any wear from protruding screws. The length of the picatinny rail is 5.025" The picatinny rail is compatible with the Generation 2 SI Defense HKG3 upper and the SI Defense .308 uppers.

SI Defense billet generation 2 upper receiver ar-15Standard Build Specifications

  • Fully machined from solid billet aluminum or forged
  • 5.56/.223 and 7.62/.308
  • Material: 7075 aluminum.
  • Coating: Black anodized to MIL-F-8625F and AMS 2471F.
  • M4 feed ramps

SI Defense billet upper AR-15 receiver

SI Defense AR-15 billet and forged upper receivers should fit most lowers on the market but SI will not guarantee fit, form, function or color match with any other manufacturer’s hardware. While we at SI Defense make every effort to manufacture aSI Defense 7075 billet aluminum upper receiver, generation 2 AR-15 product as compatible with the existing AR market as possible, we will not sacrifice quality in order to make a “universal” product.

 

 

 

 

7.62/.308 AR Upper Receivers

Because the are many different hardware manufacturers and suppliers of the 7.62/.308 receivers, these uppers are specifically manufactured to match each respective model. Our uppers will fit DPMS® parts. These models are not cross-compatible with Armalite® style receivers. Our upper has a forward assist and is fluted. We think you will find that we have the best looking, and functioning 7.62/308 receiver set on the market today.

Our 308 Generation II billet uppers are made from a solid block of 7075 aluminum billet and feature a shell deflector, dust cover, removable picatinny side mount rail and M4 feed ramps. There is no forward assist on the Gen. II. The top rail and removable side rail are machined to MIL-1913 specifications. The upper is anodized per MIL-A-8625. The side rail can be used to mount your light, laser or optic and re-distribute your weight of your rifle so that is is more balanced. The side mount picatinny rail has three 8-32 screws to mount it securely into place with a 3/32 allen wrench. The threaded holes in the upper receiver do not penetrate into the upper receiver bore, so you do not have to worry about any wear from protruding screws. The length of the picatinny rail is 5.025".

Our 308 Generation III billet uppers are made from a solid block of 7075 aluminum billet and feature a shell deflector, dust cover, forward assist and M4 feed ramps. The top rail and removable side rail are machined to MIL-1913 specifications. The upper is anodized per MIL-A-8625. There is no side rail on the Generation III upper receiver.

  • SI AR-D: Uppers will fit DPMS® lowers
  • SI AR-D Generation 2: Uppers will fit DPMS® lowers
  • SI AR-D Generation 3: Uppers will fit DPMS® lowers
  • SI HK: Uppers and lowers will NOT fit DPMS® lowers or uppers
  • SI HK Generation 2: Uppers and lowers will NOT fit DPMS® lowers or uppers

 

SI Defense generation 2 upper billet receiver will fit a DPMS style 308 lower receiver

generation 2 billet upper ar-10 dpms compatible

 

Both of our DPMS© compatible .308 receivers and the HK G3 receiver sets are made from 100% billet 7075 aluminum lowers and uppers that will fit DPMS© parts.

Please note: The HK G3 lower is not compatible with a DPMS upper, it must be modified. We will not modify a DPMS upper. You must purchase a matched set when ordering HK G3 compatible upper/lower. Because of liability concerns, we will not modify another manufacturer's product to make it fit our lower or upper G3 HK receiver. The matched set is compatible with DPMS hardware (lower parts kit and bolt carrier group, charging handle, barrels, etc.)

Because of the design on the HK G3 magazines, there is no bolt catch for the HK G3 matched set.

SI Defense HK G3 lowers will fit DPMS hardware and fit only HK G3 magazines. The magazine feed lips must be modified for proper feed and fit. Each receiver set comes with two used and modified HK G3 magazines. An instruction sheet will be included on how to modify your existing magazines. Don't worry, mags are cheap and the modifying is so easy a caveman can do it.