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Joined:
Sep 2025
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CA, USA
Posted: 9/26/2025 10:53:39 AM EDT
[Last Edit: WeR0206][Edited]
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Not sure what happened to my other thread on this. The use case for this build is a low cost shorter length SPR made with some parts that I already had on hand except for the barrel and gas block. Build list (note re: pricing, some of these parts were purchased during Holiday sales): * Upper receiver: BCM Demo Upper (# FLAT-TOP-UPPER-M4-DEMO) ($50) (thermofit) * BCG: Radian Enhanced Nitride BCG (# R0081) ($179) * Gas tube: Rosco Intermediate Nitrided Stainless Steel Gas Tube (comes with barrel) * Gas block: Rosco .750" V2 Set Screw Gas Block (# ROS-NGB-002) ($38) * Barrel: Rosco K9 16" 1:7 Intermediate 5.56 Nitrided 416R Barrel (# K9-16-HY-556-7-I) ($135) * Handguard: KAK 13" Handguard (# MO-441-1010-006) ($110) * Muzzle device: Cross Machine Tool Tactical Combat Flash Comp (QPQ Stainless) ($79) Total cost: $591 Upper build tools (1/2): https://youtu.be/9K5teuKivTs?si=95jbFddBybmM_7Jm Upper build tools (2/2): https://youtu.be/yUrGzfW89ZI?si=PAmtqU61xM2r80At Link to AR-15 upper build tools post: https://www.youtube.com/post/Ugkxl7ASgT3q4m5A1T9gGwWvzNZD85zbZXqC Link to AR-15 upper build steps post: https://www.youtube.com/post/Ugkx-OnosmRoszGgOf4Z-qEJY6IQqnokqAE3 6 Part Series of Videos Covering All My Build Steps:  AR-15 16" SPR Upper Build 5.56 (1/6): Taking Barrel Measurements and Checking Headspace #arbuild  AR-15 16” SPR Upper Build 5.56 (2/6): Installing Dust Cover and Forward Assist #arbuild  AR-15 16” SPR Upper Build 5.56 (3/6): Installing Barrel Into BCM Thermofit Upper  AR-15 16” SPR Upper Build 5.56 (4/6): Torquing The Barrel Nut and Attaching Gas Tube To Gas Block  AR-15 16” SPR Upper Build 5.56 (5/6): Installing Gas Block, Muzzle Device, and Handguard  AR-15 16” SPR Upper Build 5.56 (6/6): Things To Check Before Test Firing Barrel inspection notes: Weight: 34.6 oz (2.2 lbs) Gas system length: Intermediate Gas port size: 0.088" Gas block journal: 0.7505" Barrel Extension: 0.9975" Headspace gauge check (on fully stripped Radian bolt): 1.4636": closes 1.4646": doesn't close 1.4686": doesn't close 1.4736": doesn't close |
Joined:
Sep 2025
Posts:
8
EE: 0% (0)
CA, USA
AR Sponsor