Re: Larue or KAC M5 RAS for 20" build?
Okay, I just got a Larue catalog today, I ordered a scope mount from them. Awesome folks, all the free shit? Only complaint is the DVD wasn't the 2011, instead of 2010 Sniper Comp., because I worked with one of the guys in it at the SDM school. Haven't tried the mount yet but it looks good. Impressed with Larue already...
Anyway, I got out my rifle to mount this scope on. It happens to be that I have that rail system. I have two M5's, the regular non FF M4 version, and the URX2 mid length. I got hooked on KAC in the army and I've used just about half or more of their products at one point or another. They don't include free shit, and they aren't as personable as Larue, but they do make good shit and stand behind it. I had one non FF full length rail that I wore out, literally wore it out, the rails were all shiny and tore up and it was bent. They replaced it. I had another I accidentally ran over with a truck (good thing it was just the handguard). They replaced that too, free, even after I told them and offered to pay for it. I've heard some folks bitch about the service, but I've never had a problem. They even sent us 3 free ones when I was at the SDM school, 3 FF rail systems sent to gun junkies! But at that time companies were sending you all kinds of free shit if you had a mil ID because war was ramping up.
Turns out, come to think of it, that all the best makers run behind on orders and stand behind their shit to the point of giving you free replacements if you ask. If they don't, I quickly forget about them...
All the KAC rails are solid as hell, even the non FF M4 version clamps to the gas tube.
Now judging from the catalog and the KAC, they look a lot alike. The KAC M5 looks a little bit thicker and heavier cross sectionally, but I doubt it really matters at all. Neither one are gonna crush easy (I know, it took a truck). The KAC looks like it mounts the same way; it has a barrel nut threaded on the exterior with a bunch of holes. Two pins will fit in two of the holes 180deg. from one another when you lock the barrel down. Those steel pins fit tight and flush in the tube and line it up and prevent it from ever moving. Then the locknut, that was installed prior to the tube, is tightened down on the threaded end of the tube and a strap wrench makes it nice and tight and it doesn't come off.
I have one on a .50 Beowulf I got in '03 and it is quite solid. I figure if one was gonna work loose, it would have been that rifle and by now at least. Recently I did some work on the rifle and took the tube off, yep, still solid, needed the strap wrench and the vice to pull it off. That made me feel good.
If you squeeze the barrel against the end of the tube hard enough, I suppose you can get it to flex a bit, but I imagine that is all it is. I wouldn't mount optics on it myself, but I wouldn't on any handguard that wasn't a true one piece monolithic upper.
Bottom line? I'd go with either the cheapest one or the one you feel most comfy with. Difference looks negligible. If the sling socket in Larue is useful to you, then go with it because the KAC doesn't have that.
Now what is totally different is the URX2, but you didn't ask about it. The URX3 is the same thing but it has removeable rails on it too. They are both FF, lower profile, line up to the upper's rails perfectly, have the sling sockets on both ends, flip up from sight built into the rail, the bottom detaches easily enough but is still solid (so you can mount a 203, but it is equally nice if you just want to clean and oil the barrel) and like all KAC rails, the panels snap in and don't go anywhere and feel like a good round handguard. The URX is also solid as hell.
I didn't like the URX at first, but when I got that .300BLK AAC upper and didn't get a choice, I changed my mind. I love the thing now, just not a fan of needing a special tool to install it, but what the hell. It is kind of unique among its peers and has a fairly tight circumference considered, so I imagine it is needed.
If or when I need another, I'll be using the URX3 myself. The built in front flip sight alone makes its price competitive, no?
And for round tubes? You put the panels on the KAC tube and it basically makes it a round tube. Anyway, you can't go wrong with either company, and JP Ent., they also make VERY good stuff as well, especially for 3gun. You should check out their V-Tac. Only put rails where you want them.
