Suppressors are no longer niche accessories — they’ve become essential tools for hunters, tactical shooters, and recreational marksmen who want quieter, more controlled shooting. The right caliber makes all the difference when running suppressed, especially when balancing sound reduction, velocity, energy retention, and reliability.
Today, we’ll compare the best suppressed calibers for the AR platform: .338 ARC, .300 Blackout, 5.56 NATO, and 8.6 Blackout. Each brings unique strengths to the table, and with Moriarti Armaments’ precision-built uppers and rifle kits, you can find the perfect suppressed setup for your needs.
Best Suppressed Calibers for Your AR Platform
Suppressors don’t just reduce noise — they also tame recoil, reduce muzzle flash, and improve overall shooter comfort. But their performance heavily depends on caliber. Some cartridges are naturally suppressor-friendly due to lower muzzle pressures and subsonic loads, while others require tuning.
Key factors:
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Barrel Length – Shorter barrels generally pair better with suppressors.
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Gas System Tuning – Adjustable gas blocks or buffers optimize cycling.
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Ammunition – Subsonic vs. supersonic drastically changes suppression results.
Best Suppressed Calibers for Your AR Platform
If there’s one caliber built with suppression in mind, it’s 300 Blackout (300 BLK). Designed to run both supersonic and subsonic, it shines with suppressed rifles.
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Subsonic Loads (220gr+): Exceptionally quiet, often hearing-safe with a quality suppressor. Perfect for home defense, CQB, and stealth shooting.
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Supersonic Loads (110–150gr): Delivers 7.62x39-like ballistics with excellent terminal performance out to 300 yards.
Best Barrel Length for Suppression: 8"–10.5"
Ideal Setup: Moriarti AR-15 300 BLK Pistol Uppers with slim M-LOK handguards and SBA3 brace.
If suppression is your #1 priority, 300 Blackout is still the undisputed champ.
Best Suppressed Calibers for Your AR Platform
5.56 NATO wasn’t designed with suppressors in mind, but with tuning, it works very well. It’s still the most widely available and versatile AR caliber.
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Supersonic Only: No practical subsonic option, so suppressed 5.56 will always have the crack of supersonic flight.
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Gas Adjustment Required: Suppressors increase back pressure, making rifles “overgassed.” An adjustable gas block is a must for reliability and reduced wear.
Best Barrel Length for Suppression: 11.5"–14.5" (balances velocity & maneuverability)
Ideal Setup: Moriarti AR-15 5.56 NATO Pistol Uppers.
Great if you want a do-all AR caliber that can be suppressed but still doubles as a high-velocity defensive round.
Best Suppressed Calibers for Your AR Platform
The 338 ARC (Advanced Rifle Cartridge) is newer but making serious waves. Built for AR-10 platforms, it delivers long-range energy and excellent suppressed potential.
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Supersonic Loads: Retains energy far past 600 yards, making it ideal for hunting and extended-range shooting.
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Subsonic Potential: With heavy bullets, 338 ARC can be suppressed with surprising efficiency, though it’s still developing compared to 300 BLK.
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Barrier Penetration: Offers more punch than 5.56 or 300 BLK, especially when suppressed.
Best Barrel Length for Suppression: 14.5"–18" (maintains velocity but works with cans)
Ideal Setup: Moriarti AR-10 338 ARC Uppers with M-LOK rails and threaded barrels.
If you want suppressed precision + long-range lethality, 338 ARC is the sweet spot.
Best Suppressed Calibers for Your AR Platform
Think of 8.6 Blackout as the big brother to 300 BLK — optimized for AR-10 platforms with a focus on heavy, subsonic projectiles and devastating terminal ballistics.
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Subsonic Loads (300gr–400gr): Ultra-quiet with a suppressor, but packs enormous stopping power.
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Supersonic Loads: Capable of pushing big bullets at serious speeds for hunting and tactical applications.
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Unique Twist Rates: Typically uses a fast 1:3 twist, which stabilizes massive bullets for devastating wound channels.
Best Barrel Length for Suppression: 12"–16"
Ideal Setup: Moriarti AR-10 8.6 Blackout Uppers with SBA3 brace and suppressor-ready threads.
The ultimate suppressed hunting caliber for those who want quiet shots with maximum terminal effect.
Best Suppressed Calibers for Your AR Platform
| Caliber | Subsonic Option | Noise Reduction | Effective Range | Best Barrel Length | Ideal Use Case |
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| 300 BLK | Yes (220gr) | Excellent | 300 yds | 8"–10.5" | Home defense, CQB, tactical |
| 5.56 NATO | No | Moderate | 500+ yds | 11.5"–14.5" | General purpose, training |
| 338 ARC | Limited | Good | 600+ yds | 14.5"–18" | Long-range, hunting |
| 8.6 BLK | Yes (300–400gr) | Excellent | 300–400 yds | 12"–16" | Hunting, suppressed big bore |
Best Suppressed Calibers for Your AR Platform
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Want the quietest, most proven option? - Go 300 Blackout.
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Need versatility and ammo availability? - Stick with 5.56 NATO.
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Looking for long-range suppressed performance? - Try .338 ARC.
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Hunting with a suppressed powerhouse? - Go 8.6 Blackout.
At the end of the day, Moriarti Armaments makes it easy to build the suppressed rifle you need — with precision-machined uppers, durable barrels, and complete kits.
