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OpticsPlanet Exclusive Maxim Defense Industries RDB Roller Delayed Blowback System Up to 12% Off and Blazin' Deal w/ Free S&H — 2 models

Maxim Defense Industries OpticsPlanet Exclusive RDB Roller Delay Blowback System, Carbine Buffer, Hardened Tool Steel, MXM-47839
Maxim Defense Industries RDB Roller Delay Blowback System, CQB Buffer, Hardened Tool Steel, MXM-47838
Maxim Defense Industries OpticsPlanet Exclusive RDB Roller Delay Blowback System, Carbine Buffer, Hardened Tool Steel, MXM-47839
Maxim Defense Industries OpticsPlanet Exclusive RDB Roller Delay Blowback System, Carbine Buffer, Hardened Tool Steel, MXM-47839
Maxim Defense Industries OpticsPlanet Exclusive RDB Roller Delay Blowback System, Carbine Buffer, Hardened Tool Steel, MXM-47839
Maxim Defense Industries RDB Roller Delay Blowback System, CQB Buffer, Hardened Tool Steel, MXM-47838
Maxim Defense Industries RDB Roller Delay Blowback System, CQB Buffer, Hardened Tool Steel, MXM-47838
Maxim Defense Industries RDB Roller Delay Blowback System, CQB Buffer, Hardened Tool Steel, MXM-47838
Maxim Defense Industries OpticsPlanet Exclusive RDB Roller Delay Blowback System, Carbine Buffer, Hardened Tool Steel, MXM-47839
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Maxim Defense Industries OpticsPlanet Exclusive RDB Roller Delay Blowback System, Carbine Buffer, Hardened Tool Steel, MXM-47839
Maxim Defense Industries RDB Roller Delay Blowback System, CQB Buffer, Hardened Tool Steel, MXM-47838
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Maxim Defense Industries RDB Roller Delay Blowback System, CQB Buffer, Hardened Tool Steel, MXM-47838
Maxim Defense Industries OpticsPlanet Exclusive RDB Roller Delay Blowback System, Carbine Buffer, Hardened Tool Steel, MXM-47839
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Maxim Defense Industries OpticsPlanet Exclusive RDB Roller Delay Blowback System, Carbine Buffer, Hardened Tool Steel, MXM-47839
Maxim Defense Industries OpticsPlanet Exclusive RDB Roller Delay Blowback System, Carbine Buffer, Hardened Tool Steel, MXM-47839
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Maxim Defense Industries OpticsPlanet Exclusive RDB Roller Delay Blowback System, Carbine Buffer, Hardened Tool Steel, MXM-47839
Maxim Defense Industries OpticsPlanet Exclusive RDB Roller Delay Blowback System, Carbine Buffer, Hardened Tool Steel, MXM-47839
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Maxim Defense Industries OpticsPlanet Exclusive RDB Roller Delay Blowback System, Carbine Buffer, Hardened Tool Steel, MXM-47839
Maxim Defense Industries RDB Roller Delay Blowback System, CQB Buffer, Hardened Tool Steel, MXM-47838
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Maxim Defense Industries RDB Roller Delay Blowback System, CQB Buffer, Hardened Tool Steel, MXM-47838
Maxim Defense Industries RDB Roller Delay Blowback System, CQB Buffer, Hardened Tool Steel, MXM-47838
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Maxim Defense Industries RDB Roller Delay Blowback System, CQB Buffer, Hardened Tool Steel, MXM-47838
Maxim Defense Industries RDB Roller Delay Blowback System, CQB Buffer, Hardened Tool Steel, MXM-47838
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Maxim Defense Industries RDB Roller Delay Blowback System, CQB Buffer, Hardened Tool Steel, MXM-47838

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Questions & Answers
I have a home built AR9 with a 7.5" barrel with adjustable gas block. I sometimes run a suppressor. Would you recommend the 8.3 or 6.5oz? and why?

AR9s are direct blowback and don’t use a gas system so I think you may be confused on the adjustable gas block.

by Rigby, Verified Owner, April 17, 2025
See 3 More Answers
The description says that it works for mil-spec AR-15/AR-9. Does this in fact work with AR-15 5.56?

No, this is not compatible with a standard AR-15 direct impingement system. It will not cycle.

by boB, Verified Owner, July 4, 2025
View All Q&A You Have a Question? Ask!
Customer Reviews
Helpful Positive Review
Totally worth it by Mike, Verified Owner, June 7, 2026
Many years ago I built a 9mm AR and thought it was going to be so cool. I always hated the heavy slow recoil and with the can, there was so much blow back, gas in my face. I added weight to the buffer system to reduce the gas but it didn't do anythi...
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1/1 found this helpful
Helpful Positive Review
Highly Recommend by bafflingbs, Verified Owner, February 24, 2025
First of all, my setup, I have a 10.5 inch Stern upper, and a LRB AR15 milspec. lower and a Stern 9mm mag well adapter. I have a Rugged 3 lug muzzle device and adapter for my Rugged Obsidian 9. I’ve never really been impressed by this can. I always t...
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4/5 found this helpful
Helpful Positive Review
It actually works by Michael Edelson, Verified Owner, August 29, 2025
I regretted buying the Daniel Defense PCC at first. It's an excellent carbine, but it is just direct blowback. The hydraulic buffer softened recoil considerably but didn't do anything for muzzle rise. When I saw this roller delay buffer, I thought, "...
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6/6 found this helpful
Helpful Positive Review
Perfect fit for the SD HBPDW by BordertownUSA, Verified Owner, May 3, 2026
I can’t yet comment on its function, but it seems well made. It was a perfect fit in the HBPDW to replace the busted up buffer. I did want to comment on the negative comments stating that this makes the weapon too hard to charge. Unless there are qu...
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2/2 found this helpful
Helpful Positive Review
Excellent recoil reduction. by ClintonRH, Verified Owner, December 30, 2023
I've only shot one 2gun match and one range day with this since I installed it. Installation of the buffer was easy with the only difficulty being driving out the roll pin in my bolt to remove the weight. For testing I ran 112 rounds of a mix of 124g...
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13/16 found this helpful
Helpful Positive Review
Absolutely Worth It! by John C, September 16, 2024
Some reviews here and on YouTube state that they didn't feel much reduction in recoil. That can happen if you don't shoot often as recoil memory can be really fuzzy. For myself, I went through 2 32 round mags in my 10.5" Barrel Colt 9mm SMG then I re...
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4/4 found this helpful
Read All 49 Reviews

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Product Info for OpticsPlanet Exclusive Maxim Defense Industries RDB Roller Delayed Blowback System

Upgrading your AR9 has never been easier than with the OpticsPlanet Exclusive Maxim Defense Industries RDB Roller Delayed Blowback System! Designed by Maxim Defense Industries to transform your 9mm AR-pattern firearm into a roller-delayed blowback system, which reduces felt recoil and increases the gun's overall reliability. These AR15 Buffer Assemblies allow gas pressure to stabilize before extraction, helping you keep shooting smoothly the entire time. Plus, the RDB Roller Delayed Blowback System is easy to install, so you can make the upgrade yourself right at home.image

NOTE: The RDB System is designed specifically for 9mm AR platforms and is not compatible with other calibers. The RDB system is not full auto rated. 

Specifications for OpticsPlanet Exclusive Maxim Defense Industries RDB Roller Delayed Blowback System:

Manufacturer: Maxim Defense Industries
Color: Steel
Condition: New

Features of OpticsPlanet Exclusive Maxim Defense Industries RDB Roller Delayed Blowback System:

  • Reduces felt recoil
  • increases reliability
  • Minimizes friction for enhanced performance

Package Contents:

  • Maxim Defense Industries RDB Roller Delayed Blowback System
  • Instruction Manual

OpticsPlanet Exclusive Maxim Defense Industries RDB Roller Delayed Blowback System Orderable Models

List of Orderable Models

  • Maxim Defense Industries OpticsPlanet Exclusive RDB Roller Delay Blowback System, Carbine Buffer, Hardened Tool Steel, MXM-47839 , MPN: MXM-47839 , UPC: 680017478391 , Code: MDI-BFA-RDBS-MXM-47839
  • Maxim Defense Industries RDB Roller Delay Blowback System, CQB Buffer, Hardened Tool Steel, MXM-47838 , MPN: MXM-47838 , UPC: 680017478384 , Code: MDI-BFA-RDBS-MXM-47838

OpticsPlanet Exclusive Maxim Defense Industries RDB Roller Delayed Blowback System Unavailable & Discontinued Models

List of Unorderable Models

  • USED, Maxim Defense Industries RDB Roller Delay Blowback System, CQB Buffer, Hardened Tool Steel, MXM-47838 , MPN: MXM-47838-EDEMO , Code: MDI-BFA-RDBS-MXM-47838-EDEMO-OB-A
  • USED Maxim Defense Industries OpticsPlanet Exclusive RDB Roller Delay Blowback System, Carbine Buffer, Hardened Tool Steel, MXM-47839, EDEMO4, Condition Fair, Other , MPN: MXM-47839-EDEMO4 , Code: MDI-BFA-RDBS-MXM-47839-EDEMO-OT-D
  • USED Maxim Defense Industries OpticsPlanet Exclusive RDB Roller Delay Blowback System, Carbine Buffer, Hardened Tool Steel, MXM-47839, EDEMO5, Used, Condition Like New , MPN: MXM-47839-EDEMO5 , Code: MDI-BFA-RDBS-MXM-47839-EDEMO5
  • USED Maxim Defense Industries OpticsPlanet Exclusive RDB Roller Delay Blowback System, Carbine Buffer, Hardened Tool Steel, MXM-47839, EDEMO3, Condition Fair, Used , MPN: MXM-47839-EDEMO3 , Code: MDI-BFA-RDBS-MXM-47839-EDEMO-US-D
  • USED Maxim Defense Industries RDB Roller Delay Blowback System, CQB Buffer, Hardened Tool Steel, MXM-47838, EDEMO2, Condition Like New, Inspect and Rebox , MPN: MXM-47838-EDEMO2 , Code: MDI-BFA-RDBS-MXM-47838-EDEMO-RE-A
  • USED, Maxim Defense Industries RDB Roller Delay Blowback System, CQB Buffer, Hardened Tool Steel, MXM-47838 , MPN: MXM-47838-EDEMO , Code: MDI-BFA-RDBS-MXM-47838-EDEMO-RE-B
  • USED Maxim Defense Industries RDB Roller Delay Blowback System, CQB Buffer, Hardened Tool Steel, MXM-47838, EDEMO1, Used, Condition Fair , MPN: MXM-47838-EDEMO1 , Code: MDI-BFA-RDBS-MXM-47838-EDEMO1
  • USED Maxim Defense Industries OpticsPlanet Exclusive RDB Roller Delay Blowback System, Carbine Buffer, Hardened Tool Steel, MXM-47839, EDEMO1, Used, Condition Fair , MPN: MXM-47839-EDEMO1 , Code: MDI-BFA-RDBS-MXM-47839-EDEMO1
  • USED Maxim Defense Industries OpticsPlanet Exclusive RDB Roller Delay Blowback System, Carbine Buffer, Hardened Tool Steel, MXM-47839, EDEMO2, Used, Condition Fair , MPN: MXM-47839-EDEMO2 , Code: MDI-BFA-RDBS-MXM-47839-EDEMO2
  • USED Maxim Defense Industries RDB Roller Delay Blowback System, CQB Buffer, Hardened Tool Steel, MXM-47838, EDEMO3, Used, Condition Like New , MPN: MXM-47838-EDEMO3 , Code: MDI-BFA-RDBS-MXM-47838-EDEMO3
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Last updated 2026-07-06 UTC.