Build of materials:
- PSA 16" CLASSIC FREEDOM 9MM 15" KEYMOD UPPER W/BCG & CH $419
- PSA STRIPPED BILLET 9MM LOWER W/MAG CATCH ASSEMBLY AND EJECTOR $119
- Geissele 2 Stage G2S Trigger $160
- JP Enterprises Trigger Spring Kit AR-15 3-1/2 lb Reduced Power $11
- New Frontier Armory 8 oz blow back buffer $32
- .308 Carbine buffer spring $6
- Commercial carbine buffer tube (spare parts)
- Magpul Stock MOE FCS Fixed Carbine Stock $24
- Ergo grip $14
- Lower parts kit without fire control group (spare parts)
- C-More Railway 8 MOA TRW $204
- CMR-206 RAIL MASTER® UNIVERSAL GREEN LASER SIGHT $80
Build Notes:
Putting it together is the same as building any AR. However, there were a few tweaks.
- I used an 8oz buffer plus a .308 carbine spring after having a several out of battery discharges. I also keep the BCG very wet.
- I used the JP low power spring on the trigger and kept the stock Geissele G2S hammer spring, trigger breaks at 2.5 lbs. Note that the Geissele two stage triggers work with the PSA hybrid bolt, but not the Super 3 Gun. CMC triggers also don't work because the hammer is too short for the bolt to reset.
- I'm not entirely happy with the buffer and spring combo and might experiment with that a bit, but the most noticeable change in recoil and dot bounce is affected by ammo. Using Freedom Ammunition 124 grn reloads as a baseline, Atlanta Arms 147 grn has less recoil, and Stand1 Armory 147 grn chubbies has very little recoil.
- The C-More is sighted in at 25 yards, and the Crimson Trace laser is sighted in for 5 yards. If I decide to shoot it in a 3 Gun style match, I will probably switch out the laser module to one with a smaller MOA. Both the C-More and laser use the same battery, which is convenient.
- Still undecided on about a compensator, with so many coming out I'm waiting until there's a consensus. For now, I removed the birdcage flash hider and replaced it with a thread protector.