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M4A1 FSP Rail Interface System (RIS) II


Out of stock

Additional Information

Manufacturing # / SKU 01-004-08030
Restricted Shipping Yes
Product Weight 17.1 oz
Rail Length 12.25"
Width 2.23"
Height No
Inside Diameter 1.15"
Barrel Nut Steel (For Patented Bolt-Up System)
Gas System Length Carbine
Free Float Yes
Continuous Upper Rail Yes
Integrated Sling Swivel Attachment Point No
Manufacturer Daniel Defense

M4A1 FSP Rail Interface System (RIS) II

Daniel Defense is the Sole Source Provider of the RIS II to the United States Special Operations Command!  The Daniel Defense Rail Interface System (RIS II) was designed at the request of the United States Special Operations Command (SOCOM) for the SOPMOD II program. SOCOM had a specific requirement for a free float M203 solution and Daniel Defense responded, designing a revolutionary product to meet the government’s need. The Daniel Defense RIS II allows the individual operator to free float the M203 grenade launcher without additional parts. As importantly, special tools are not required to mount the M203 grenade launcher. This was accomplished by integrating all of the needed parts to free float the M203 into the rail itself.

The Daniel Defense RIS II M4A1 FSP feature a cut out in the top rail to accomdate a standard front sight base on a carbine length gas system.

The Daniel Defense RIS II free-floating Picatinny rail systems are designed to allow individual operator to quickly, and without special tools, mount M203 Grenade Launcher and precisely mount SOPMOD accessories to host weapon without effecting point of impact. The Daniel Defense RIS II is an innovative upgrade to the M4 platform and is available for commercial purchase directly from Daniel Defense or any authorized distributor.


  • Free Floating Barrel Design
  • Uninterrupted Upper Rail Platform
  • Aircraft Grade Aluminum
  • Hardened Steel Barrel Nut
  • Grade 8 Military Specification Fasteners
  • Mil-Spec 1913 Picatinny Rails

Materials & Construction

  • Material: Aircraft Grade 6061-T6 Aluminum
  • Finish: Military Specification Flat Dark Earth
  • Length: 12.25"
  • Width: 2.23"
  • Weight 17.1 Ounces
  • Inside Diameter: 1.15"
  • Made in the USA!

Installation Requirements

Our Bolt Up System Barrel Nut Wrench is required for installation

All Daniel Defense products carry a 100% satisfaction guarantee against defects in original materials and workmanship. If your Daniel Defense product shows evidence of such defects, Daniel Defense will make every accommodation to fix, repair, or replace your product in the most expeditious manner possible. Daniel Defense does not warranty products or damage caused to our products by the correct or incorrect installation of other manufacturer’s products. Be sure to retain your sales slip as proof of purchase date when making a claim.

Product Reviews

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Customer Reviews 4 item(s)

Rail availability
Would like to know when the rail will be available?
Review by Jr / (Posted on 1/3/2018)
Rail availability
Would like to know when the m4a1 ris 2 rail will be available. The public would also like to purchase. If you have time to make other rails,why can't you make the ris2 ? So, the public,not just military can purchase. Have read where you would like people to report the copies of your rails. Don't think people are going to report it if that's the only place they can get them. I myself am holding out for the real thing. The longer you keep the rail from the public,the more people price gouge. I've been a fan of Daniel defense for a long time,& bought many of your product's over the years. Would like to continue. It doesn't look good when airsoft people can get a licensed copy of the rail,& the people that want your real product's can't.
Review by Jr / (Posted on 12/31/2017)
Cannot go wrong!
Amazing rail. Strong , durable, and light compared to others. Used it whilst in the military , and now use it as a Civ shooter cannot go wrong with it. The extra real estate is was always a plus when using lights and lasers. I personally like the feel of the cheesegrater and have no reason to go to KeyMod or MLOK. People will often discuss the weight difference , well comparatively speaking I would sacrafice some weight , for the extra real Estate, modularity, and strength of the system. I have never had a bolt walk on me , and can say it is the most durable rail I have personally used in a work capacity or a plinking capacity.
Review by Guard66 / (Posted on 4/5/2016)
solid rail system, plenty of realestate to mount what ever you want with out weighing down your gun. highly recomend. Review by Seth / (Posted on 2/13/2011)
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