I’m not a pro/SME, but I have spent some time with both the RAS and RIS II (M4A1 with and without FSP.) I had an RAS on my 6920 for a short while, and I just didn’t care for it. Could be the well-worn (used) set I had, but it wasn’t quite as tight as I like. I picked up a used 14.5" BCM upper w/perm FH with the RIS II 12" and no FSP, and it is by far and away my favorite rifle to shoot. I use an Aimpoint PRO on mine, MBUIS, and getting an Inforce WML for mine. (After not being happy with mounting a Streamlight Polytac.) I don’t find it to be unbalanced to shoot at all, nor too heavy.
The FSP model on my 6920 doesn’t feel as mobile. I don’t know if it is the extra weight of the FSP and bbl as well as being at the end of the rifle, but they have very different feels. I have no problem running around with the 6920 w/FSP all day long, it’s not that it’s unbearable, but when I bring both, the 6920 is just a backup.
I appreciate the feedback guys, I decided to go with a block 2 style rail. I figured it would be superior but I just wanted to see what others thought of it.
RIS II all day, any day. There is literally no situation where I would EVER chose an M4A1 with RAS/RIS over an M4A1 with a RIS II. None, period.
Short RAS means I have to have a cramped grip on the gun. It means I don’t have free floated barrel. It means my light and laser are too far back and create lots of shadow and back splash against my barrel. It means my gun will suck to shoot using various supported positions and from various forms of cover and concealment. It means my gun won’t point as well since I can’t drive the muzzle as well. The list to keep going but those are high points.
I wouldn’t it call it a block I but I did have the Kac ras. While it was nice to have the rail I felt it was too cramped for my style. This pic is about 3 years old.
I now run a block II ish setup. The sights are getting replaced as soon as I get a pair of Kac sights.
OP, Im not quite sure why you are stuck on the RIS II if you are concerned about weight. The RIS II was designed around a specific set of requirements namely to be able to remove the bottom rail to mount an M203. If you do not need to mount a M203 then why not choose any of the other lighter FF forends out there?
I bought a SOCOM upper from Bravo last year… I like it and the weight doesn’t bother me… but I didn’t shoot it too often after setting it up. THEN… I tried the ELW from Bravo and short of a non stop full duece gear emptying fire fight in Iraq or Afghanisan, the ELW does everything just as well.
I have too many ARs in rotation… the SOCOM is going to be in the back of the safe for a little while.
I just picked up a pair of 14.5 socom profile barrels. Have one pinned /welded, will be sending the other off next weekend. I will say I can tell a weight difference. But I don’t believe it to be much of an issue. I plan on running a suppressor on the 2 rifles, which was the big reason for seeking them out. If it wasn’t for wanting to get into silencers, I most likely would have looked at a different option.
I have used the KAC, but both of my rifles have gone to the DD ris 2 fsp. Honestly I only need about a 8-9 inch rail. I stand at 5’8 with T-rex arms and fingers to go with them. I use a c clamp style grip right behind the FSP, with a couple fingers directly under the FSP, and a surefire sr07 switch on top. The additional rail completely eliminated any shadow from my light. Big deal? Probably not, but it was a cool product of a rail that I find pleasing. Not to mention I like that I can take the bottom off with relative ease for cleaning, and the lock up of the rail to the upper inspires a great deal of confidence in me. Its a bit heavier but I think over all it offers a lot more than the KAC
The SOCOM profile approaches a more logical, taper like shape. Thus, the additional weight isn’t completely awkward.
Likewise… the ELW barrel isn’t THAT thin under the handguard… but it’s taper shape to the thinnest portion, in front of the gas block, give it the feel of a complete pencil skinny barrel.
Both of these examples lead me to what others long ago concluded… the govt profile is completely retarded.
I had the KAC on my Colt M4A1 but it always felt a bit cramped. Swapped the KAC for a RIS and it made the gun feel and handle like a totally different animal. I think I’m actually quicker on target transitions than with the shorter rail-- having my support hand out farther on the barrel. Even with the heavier SOCOM profile, the gun does not feel front heavy and is perfect for my shooting style. Plus, I like having the light out near the barrel at 12o’clock.
That funny, having had both, I totally prefer the 7" rails. The more weight toward the back/middle of the gun, the more balanced it feels to me. I also don’t mount a ton of crap on my rail or hold it by the muzzle so I can’t think of any reason to have a longer/heavier rail.
The main reason that I run a KAC RAS at home is because that is what my issued M4 at work has, and I want the rifle I train with at home to replicate my issued rifle. If I had the freedom to choose anything in the supply system, I’d definitely go with the RIS II. Alas, I am in the big army, and use what I am issued.
Man, this is a tough decision. Picked up a Colt 14.5" SOCOM profile barrel this week. Looking to get a 6920 OEM to swap the barrel onto for a clone build. Was going to just use the KAC RAS and a M4 Carbine stock since they’re so iconic. Until I clicked on a few threads here, I had no idea about the existence of the Block II rifles. They a relatively new development? RIS II rail just makes the rifle look more like any regular AR15 now.
