R
RelentlessRobxsmall things to mention
Reviewed on May 15, 2026Verified with Build
works great. wish it came pre lapped
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Rosco Manufacturing Bloodline 5.56 AR-15 Barrel M4 Carbine - 14.5"
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Rosco Manufacturing
Overview
The Rosco Manufacturing Bloodline 5.56 AR-15 Barrel is a 14.5-inch M4 profile barrel designed for use with a carbine-length gas system. With a twist rate of 1:7, it effectively stabilizes a wide range of bullet weights, making it versatile for different ammunition choices. This barrel is commonly found in builds that emphasize a compact design while maintaining the reliability and performance expected from a 5.56 NATO caliber setup.
Specifications
MPNBL-145-M4-556-7-C
Caliber5.56 NATO
PlatformAR-15
Action TypeSemi-Auto
ColorBlack
Barrel Length14.5
ComplianceStandard
Thread Pitch1/2x28
Gas System LengthCarbine
Barrel ProfileM4
CoatingQPQ/Nitride
Twist Rate1:7
Rosco Manufacturing Bloodline 5.56 AR-15 Barrel M4 Carbine - 14.5"
August 2026 on GunPartPicker
Rosco Manufacturing Bloodline 5.56 AR-15 Barrel M4 Carbine - 14.5" was the most added barrel on GunPartPicker in August 2026, ahead of the FAXON Firearms 16" 223 Wylde Match Barrel Stainless Steel Black, with about 6% of all barrels added to builds. That's its 4th straight month at #1. Builds with this barrel are nearly all chambered in 5.56 NATO, nearly all on carbine-length gas, and mostly AR-15 (82%, then AR-10 18%).
Availability is good: it was in stock at one retailer or another nearly every day in August 2026, and today 6 of the 7 retailers we track have it in stock. The best price crept up from $131.49 to $137.50 over August 2026. Buying today, the lowest price is $147.60 at KY Gun Company, above August's low of $131.49, so a better deal may come back.
Updated · from real builds on GunPartPicker · Prices checked · refreshed daily across 31 retailers
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We ranked every barrel by how often it shows up in real builds on GunPartPicker.
Read the guide: AR-15 Barrel Length & Brand Report →Frequently Built With
The part most often added in each category by the 368 builds that include this one
Bravo Company Mfg Upper Receiver Assembly w/ Laser T-Markings, Hard Coated Anodized - 4-UR-M4
Upper Receiver$129 · out of stockin 111 builds
Aero Precision Stripped M4E1 AR-15 Lower Receiver - Special Edition - Freedom
Lower Receiver$155 · out of stockin 48 builds
Midwest Industries Suppressor Series M-LOK AR-15 Handguard - 10.5"
Handguard$155in 46 builds
Aero Precision AR-15 Breach Charging Handle Ambidextrous Small Levers
Charging Handle$69 · out of stockin 79 builds
Aero Precision AR-15 5.56 BCG W/C158 Bolt - Aero Logo - Phosphate
Bolt Carrier Group$149 · out of stockin 54 builds
Geissele Automatics AR-15 SSA-E X Lightning Bow Trigger
Trigger$335in 48 builds
Build Configuration Breakdown
Aggregated and anonymized data showing how builders use this product
PlatformBased on real build data showing which platform (AR-15, AR-10, AR-9) builders pair with this product.
81.6%
AR-1581.6%
AR-1018.4%
Builds Featuring This Part
See all 91 →Builds in the community that include the Rosco Manufacturing Bloodline 5.56 Ar-15 Barrel M4 Carbine - 14.5"
| Build | Parts | Total |
|---|---|---|
 | 23 | $4026.81 |
 | 16 | $4650.94 |
 | 17 | $1490.46 |
 | 11 | $1149.19 |
 | 14 | $2274.64 |
 | 22 | $1065.29 |
| 8 | $697.16 |
 | 22 | $1011.53 |
| 10 | $747.80 |
| 28 | $2656.56 |
 | 14 | $5026.85 |
 | 12 | $2331.37 |
Customer reviews
4.8out of 5
4 global ratings
Top reviews
J
Jamie_arexcellent
Reviewed on May 8, 2026Verified with Build
twist rate stabilized everything i fed it
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B
BradenKyle782014Rosco 14.5 M4 carbine groups
Reviewed on April 30, 2026Verified with Build
Rosco Bloodline 14.5 inch barrel in M4 contour groups consistently sub 1.5 MOA. Carbine gas at 14.5 is a bit harsh but it cycles reliably. Chrome lined for longevity. Solid mid-tier barrel choice.
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C
clarkclint10104Rosco 14.5 headspace good
Reviewed on April 22, 2026Verified with Build
Rosco Bloodline 14.5 inch M4 carbine barrel had correct headspace out of the box. Standard mil-spec gas port. Cycles 5.56 reliably with M193 and M855 ball. Chrome lined for longevity. Drops in to a standard upper with no fitting.
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