Anyone have experience with DD M4A1 RISII?

AR/M4 AR Technical Discussion
1

Hey all,

Was interested to know if anyone here had any experience with the Daniel Defense M4A1 RISII rail? I’m interested in using one in a build, but I don’t know what gas-blocks it is compatible with. I’d appreciate any firsthand info anybody could provide. Thanks.

2

Anyone…
Anyone…
Bueller?:slight_smile:

3

I have the MK18 version, the workmanship and design of the rail IMHO is the greatest ever designed by DD.

4

gotm4,

If I may ask, what gas block did you use with the Mk18 rail? On the DD website, they refer to a Mk12 Low Pro gas block being used with the Mk18 and M4A1 RIS II rails, but I cannot find one of these anywhere. The two gas block’s I’m considering using for my build are the Noveske and the LaRue, do you know if the rail would clear either of these two gas blocks?:confused: Also, is there a specific barrel nut wrench needed to install this rail as with the DD Lite Rail? Thanks.

5

I shaved the FSB to fit under the rail.

6

Yes, I have been using one for awhile, though its not an easy rail to find.

Its an outstanding rail, and the Vltor block would certainly be high quality gas block to use. The Daniel Defense low profile Gas Block is another one to consider as well.

7

gotM4,

I see. Do you happen to know the interior diameter of the Mk18 rail? Also, does this rail require a specific/proprietary barrel nut wrench for installation? Thanks.

8

Stickman,

What length barrel are you using in the build pictured above? I was considering using a 14.5" M4 barrel on my build.

9

14.5".

10

Stickman,

The build looks good. Also, what can is that you have attached in the first picture? Thanks for the info.:smiley:

11

Its the AAC M4-2000.

12

Stick,

I see. Thanks. Love the AAC cans.:smiley:

13

I don’t know the internal dimensions but the VLTOR will fit. The RIS II rails require the use of the DD Lite Rail AR15 wrench. I shaved my FSB because I wanted a pinned gas block and it’s the easiest way to do without having to buy a gas block.

My typical ‘shaved’ FSBs look like this before refinishing with Norrells.


Like this after refinishing.

14

gotM4,

How are you securing the shaved FSB/gas block to your barrel? Does it still secure using the original taper pins or what?:confused:

15

He is cutting down the gas block/ front sight, and reusing the taper pins to get a solid gas block that won’t loosen or move. Its also cheaper than buying another block, though it certainly does take up a little time.

16

Thanks Stick!:slight_smile:

17

if you want the mk12 gas block, get the badger one. that’s the one.
I got mine from brownells.

18

Just about all low profile gas blocks will fit

I used DD RISII rails for a 458 Socom build. The 458 has a huge barrel diameter for obvious reasons , so I had to use a bull barrel gas block ( PRI .936" dia )

This huge gas block does not touch the ID of the rail anywhere, so I find it hard to believe that any low profile gas block for a .750 barrel dia would touch

I just had to pull the rail on half way, install the gas block then finish mounting the rail. The gas block was to large to fit in from the rear

BTW , I have used lots of DD , Larue and PRI forends and this RISII is my favorite by far

You should not buy the DD Lite rail wrench because it will just give you an excuse to buy more Lite rails ! Seriously , for the $20 just buy it. Not worth your time dicking around with a CAR stock wrench

As you can see this monster gas block is not touching the ID of the rail

19

trg42,

Thanks for the update. I appreciate the first hand info.:smiley:

20

Exactly. The ‘shaved’ FSB works very well under a RISII Mk18 rail. Here’s some pics of mine. It’s held on with the same two factory/OEM taper pins that hold on the unmodified FSB. Very secure…



I like the allen screws I added to mine better than the bladed screwdriver screws normally provided with the Omega and RISII rails. I believe they will hold up better over time and have a cleaner look.