I have never used a rifle with what some seem to be using now, a Keymod rail, or an Mlok, although I've held them and they feel good, but don't know whether either is a good long term idea or not. I'm building a nice rifle and am still leaning toward using a 4 rail since it seems to offer a lot more versatility (plus all my stuff mounts on it, whereas it probably would take some time to adapt to a keymod mount system).

Thanks for sharing your experience and thoughts.

I have changed all of my quad fails to keymod rails. They're very comfortable in the hand and less bulk when attaching stuff to it.

Thanks. I also added the Mlok system to my question, not that it needed to be more difficult to choose.

Keymod is much lighter than a quad Picatinny rail. All my new builds will be keymod.

I have builds with quad rails, key mod and mlok. Its all about preference. If you like they way one looks better than the other than buy it.

I would suggest an MLOK or Keymod. They are lighter, feel better in the hand, lots of selections, and they hold accessories just fine if installed properly.

I have a new infatuation with Geiselle mloks. I think they are a special kind of quality.

I have 2 as well as 2 quad rails.

Its all good.

I'm into picatinny man!

Longtime quad fan here but I'm considering picking up a URX 4 MLOK. I don't have a great excuse for using quads as I don't hang that much stuff off the rifle but I guess I'm partial to the aesthetics.

The weight savings are pretty significant.

I love quad rails and can honestly say I'll always own at least one gun with one.  I however have started using MLOK rails for comfort and the smaller OD of them.

FPNI
Quad rails are ass.

I still like high end quad rails, most my rifles have them.  But I like some slim rails too.

Well, if anybody cares.....I went with a quad rail even though they're not as comfortable, they're larger, and they weigh a bit more. Reason--after looking at quite a few of the alternatives, I can't convince myself that any of the other rail systems will take the abuse a quad will tolerate. Time will tell.

Barring super light weight or thin rails, I think that most other rails would hold up far past other major components of the rifle/pistol would break. I have mlok rails and intend to stay with those over keymod rails. I just prefer mlok rails for aesthetic reasons. However I will be adding LaRue quad rails into my collection soon.

There's a reason why quads have fallen out of favor, and it isn't a marketing fad. If marketing were the reason, the industry would still be force feeding us quad rails, because rail covers made for an added accessory that sold like hot-cakes. The fact is, full length rails are awkward and uncomfortable, and the buyers demanded a product that didn't require covering up with more accessory parts. It is interesting to note that the biggest selling M-Lok and KeyMod accessories are, in fact, rail sections, but that is slowly turning as more and more accessories become directly mountable to those platforms. People will always use rail sections for older equipment, but eventually they will fade further. Especially if .mil decides to use something else.

One of the best things to come away from the failed XM8 project was the PCAP (Picatinny Combat Attachment Points), which tells us that the .mil folks want something other than the rail, as well. It remains to be seen if they will have the logistical fortitude to move away from rails altogether, but the desire is obviously there and some small components are making limited use of alternative systems.

One of the reasons the PCAP failed was because we were fighting GWOT on two main fronts and when you're already vested in the parts for 1913, you stick with it because it's doing it's intended job. Another reason PCAP failed because HK wanted to be the sole source provider of all things PCAP, and that just will not do in the days of off the shelf technology being ordered locally and added to the supply system and FSC's given as well as NSN's.

I always see the frothing of the mouths for all things 1913, but how did 1913 get here to begin with and if there never was a 1913, where would we be now?

1913 is sturdier than mlok or keymod. Show me one ACOG, Aimpoint, or some other glass that will come in any other mount than a 1913? Show me. Show me why all BUIS's come in 1913 attachments and nothing else, SHOW ME WHY. There's a very good reason for this to begin with.

And so with that said, why should we the taxpayer, want the fortitude to replace so many things that already work so well and can kill just fine just so you can see what you like in the hands of the troops? That makes no sense at all and this is not how it actually works. You cannot call it logistical fortitude if you do not know how logistics even works. Those who do use alternatives also have a separate budget, meaning they can afford to piss away dollars because they do some very special things that the conventional units cannot do, and are used appropriately.

Quads have not fallen out of favor, they are still being sold otherwise they would have the facts to back it up that they have dropped off the planet, over shaddowed now? Yes they are. Full lengths are heavy, I will give you that. But why on earth would you even want a full length quad let alone a full length keymod or mlok? I sure as heck don't and never will. No wonder they are heavy then to begin with and there are mlok's and keymods that are almost just as heavy as quads but people here flock to that company anyways and give the same arguments as you

1. The 9.5" Super Modular Rail MK8, an Mlok, is 10.3 oz. installed
2. Daniel Defense Omega Rail, a quad, mid length, is 9.8 oz installed

But muh weight savings when I don't get a quad!!!

No, 1913 will be here for a long time no matter if you like it or not and not be phased out, just used less to give more room for muh "ergonomic" 20 mile long FF so we all can be a costa every where we go.

If you had just spoke about your own personal preferences instead of saying things that were not actual facts and just an opinion, I would not have commented on your post at all.

I prefer a good light quad that is short so I can use it for my SBR. It has a fore grip that I use to get a better grip due to the short length of a 10.5 with the thumb break method and is solid.

For my mid lengths I do prefer an Mlok in preferably 10" to 12" only. I keep things simple and I do not want my free float a mile long where using a front BUIS is an actual chore and can take me out of the fight in a bad situation if my optics are dead or knocked out. I actually use my stock and extend them so I can get the perfect sight picture so a million mile long FF will simply not do and is too much unnecessary weight.

As for keymods, well that is up to the user as it simply will not do for this user meaning ME and I will never care to own anything in keymod as it does nothing better than an Mlok or a short length quad in my FWIW experience, and it really looks horrible and cheap, un-innovative really.