Sionics Weapon Systems 12.5″ Standard Upper Receiver Group – NP3 BCG – Radian Charging Handle

5R Rifling:

Our new 12.5” barrels utilize 5R Rifling.  5R Rifling helps fight bullet failure due to a softer angle on the sides of the lands vs. conventional style rifling that utilizes 90° corners of the lands, which is a very hard edge.  Furthermore, with 5R, you have 5 lands in the bore of the barrel.  The odd number of lands does not directly oppose one another. The combination of these two things deforms the bullet less – less distortion to the bullet jacket when the bullet makes the jump from the case into the rifling.  This helps fight bullet failure and increases the inherent accuracy of the barrel.  Lastly, the gentler edges of lands on the 5R Rifling allow easier cleaning of the bore.  The 90° corners of conventional rifling make it harder to reach lead and other contaminants when cleaning.  The softer edges of the lands on 5R Rifling allow for a much more thorough cleaning process.

Gas Port:

In terms of gas port sizing, we went with a perfectly sized port that will be optimal for both suppressed and unsuppressed use. Just like all of our barrels, we do not believe in over-gassing our platforms. Our new 12.5″ barrel is no different, you will notice an extremely pleasurable shooting experience. Our 12.5″ barrel has an unmatched recoil impulse and less wear and tear on your internals.

New Rail Length:

Our new 12.5″ Upper Receiver Groups will include our new 11.8″ Rail as well, which allows for the tightest and most minimal gap between silencers and the rail itself. Take a look at our product picture for an example of the perfect fitment!

Configuration-

AR15 Style Upper Receiver Group, 5.56mm NATO
Upper Receiver: 7075 M4
Barrel: SIONICS 12.5” Medium Contour, 41V50, NATO Chamber, 1:7, 5R Rifling, Chrome Lined, Air-Gauged, Radiograph and MP Inspected
Gas System: Carbine-Length – Direct-Impingement
Muzzle Device: A2 Flash Suppressor
Bolt Carrier: SIONICS 8620 M16 Phosphate Bolt Carrier included with options to upgrade to NP3  Coated with use of Ned Christiansen’s OCKS (Optimized Carrier Key Screws)
Bolt: SIONICS Carpenter No.158, HP/MPI Tested, NP3 or Phosphate Coated, Black Insert and Sprinco 5-Coil Heavy Duty Extractor Spring
Charging Handle: GI or upgrade to a Radian Raptor – Ambidextrous
Hand Guard: SIONICS 11.8″ M-LOK with 5-Slot Picatinny MLOK Adapter

Sights: No Sights included w/ option to upgrade to Magpul MBUS Pro Front and Rear