LMT’s 12" Piston Barrel vs. Reality - How Well Can an SBR Group?

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In this video, I put the LMT 12” 5.56 piston barrel through a full inspection and 3x 30-round group test to see how it really performs.

This chrome-lined barrel is proprietary to the LMT MRP platform and includes their selectable gas block and op rod. Thanks to Roy at Weapon Outfitters for loaning it in for testing!

🔧 What’s covered:
– Barrel inspection (gauging, headspace, borescope footage)
– Full shooting setup details
– 30-shot group tests at 100 yards with:
    ▪ Winchester M193
    ▪ AAC 77gr OTM
    ▪ IMI Razor Core 77gr

Each group was fired under consistent conditions using a Vortex scope, Geissele SD-3G trigger, A5 buffer system, and measured using Mantis X10 and Garmin C1 Pro chronograph. A-ZED scores are calculated for performance benchmarking.

📊 Highlights:
– M193 group showed extreme horizontal stringing
– AAC 77gr (2700 fps)
– IMI Razor Core delivered the best overall A-ZED score
– Discussion on gas feel, ejection patterns, and velocity comparisons

Is a 12” piston AR barrel really viable for precision-focused builds? Watch the full breakdown to find out.

👇 Let me know your experiences with LMT barrels or these ammo types in the comments!

💬 Special thanks to Roy at Weapon Outfitters
💥 Support the channel or find my gear here: https://campsite.bio/prestonmoore
📦 Tip the channel with a Super Thanks if you enjoy this kind of deep-dive content!

#AR15 #LMT #PistonAR #BarrelTest #556 #GroupTesting #ChromeLined #WeaponOutfitters #IMIRazorCore #AAC77gr #M193 #AZone #A-ZED #ARAccuracy #ShortBarrelAR

0:00 Intro
0:17 Specs
0:58 Inspection
3:08 Shooting Setup
4:55 Winchester M193
7:17 AAC 77gr OTM
9:43 IMI 77gr Razor Core
11:34 Overall Results