Free Shipping & Free Returns*

FREE SHIPPING on Over 250,000 Products

Shop now and get Free Value Shipping on most orders over $49 to the contiguous 48 states, DC, and to all U.S. Military APO/FPO/DPO addresses.

Enjoy our FREE RETURNS

We want to ensure that making a return is as easy and hassle-free as possible! If for any reason you are not satisfied with your purchase, simply return the item within 30 days of receipt, and we'll cover the cost of return shipping. Learn more about our Return Policy.

Shopping Cart
Daniel Defense M4A1 FSP Rail Interface System RIS II
$538.00 $501.00 Save $37.00
View Product
Compare (0)
Most Helpful Positive Review No bull, the only PROVEN rail.
There is nothing wrong with other manufactures rails. Buy what you like. The truth is these DD M4 and MK18 rails earned their reputation on the battlefield. They are heavy, bulky and the mounting system is “old” by todays standards. But the mounting system works. Dropped off the back of a 7 ton, or used to open a stuck latch on an AAV your weapon will still hold acceptable battlefield zero. Or just pick one up for a clone. Stop complaining it is “heavy” go to the gym…
Show
Sort by
Filter by

best hanguard

by jswizzle, Verified Owner from VA, United States Written on July 22, 2025
Best handguard ever created. Yes the barrel nut wrench comes in the package. I mated this to a contract overrun 11.5 inch dd upper, placed a Hera arms linear comp and everything fits and looks exactly as I intended.
Would recommend: Yes
Was it helpful to you? Yes | No

Daniel Defense ris ll fsp rail

by Sheldon Sanderson, Verified Owner from TX, United States Written on February 15, 2025
Arrived in excellent condition just what I needed for my block ll build
Would recommend: Yes
Was it helpful to you? Yes | No

Looks good and high quality

by Jacob, Verified Owner from FL, United States Written on December 25, 2023
Fit on my sw mp15 pretty easily. It's solid. Would recommend.
Would recommend: Yes
Was it helpful to you? Yes | No

Top Tier Rail

by rottensuushi, Verified Owner from ID, United States Written on August 13, 2022
Rock solid lockup, aesthetically pleasing, and exactly what you need if you're doing a block II build! Its built like a tank, lets you retain your FSP if you already have an upper or barrel with one, however bear in mind quality comes at a price, and the RIS II is pretty dang heavy. But if you want a guarantee that anything like a PEQ or what not will hold zero, this is the rail for you.
Pros:
  • rock solid
  • Aesthetically pleasing to the eye
  • front sight post
Cons:
  • Heavy
  • Expensive
Would recommend: Yes
1 of 1 found the following review helpful.
Was it helpful to you? Yes | No

Great Rail for your Block II build!

by Brando, Verified Owner from WI, United States Written on February 12, 2021
Installed in conjunction with a Colt 14.5” SOCOM heavy barrel. Attaches to the receiver nicely, retains your FSP, plenty of space for attaching extras, etc. Was my first DD rail and bought for a specific purpose, but after installing and handling it, I think I’ll check out their other rail offerings for future projects. Thing is built like a tank!
Best Used for:
  • Front sight post
  • 14.5 barrels
Would recommend: Yes
2 of 2 found the following review helpful.
Was it helpful to you? Yes | No
There are no reviews that match your criteria. Would you like to review this product?