light weight rail or light weight barrel

[breakingtime91]

So, I have been debating this for a little bit.

Light weight barrel or light weight rail.

I have two uppers:

-one that has a light weight barrel and a centurion free float quad rail.

-one has a govt profile barrel and a bcm mlok rail.

Both handle and feel comparable for weight, the quad rail gives more rigidity and heat resistance while the mlok is slim and comfortable. Which would be your preference?

[HeavyDuty]

Honestly? For a general purpose AR the lightweight barrel with the lightweight rail.

[Darth_Uno]

Depends on your use. But if I ever went on a de-clutter kick, the two I’d keep are my uppers with BCM ELW barrels (11.5 and 14.5).

Mlok won the quad-vs-mlok-vs-keymod battle. You’d at least want a full rail on the top though if you plan to have both a front sight and light switch. Nothing wrong with quad though if you just like it better, which is a good enough reason to have it.

[HeavyDuty]

Does the LW with Centurion use the same rail mounting system as their MLOK rails? Maybe a simple rail swap will get you the best of both worlds - their stuff is first rate.

[littlejerry]

Why do you need a rigid rail? Is your primary sight mounted to it?

[HeavyDuty]

Why do you need a rigid rail? Is your primary sight mounted to it?

Not the OP, but having a free float for grip is generally preferable.

[littlejerry]

Not the OP, but having a free float for grip is generally preferable.

Of course, but he is comparing the relative stiffness of his two free float rails. I'm asking what measurable or tangible benefit does the stiffer rail offer.

[HeavyDuty]

Of course, but he is comparing the relative stiffness of his two free float rails. I'm asking what measurable or tangible benefit does the stiffer rail offer.

Got it. I was reading the question as in overall preference where rigidity was one factor. I personally go for light weight slim handguards and lightweight profile barrels, at least on some of my ARs. I like my general purpose carbines that aren’t magnified to be light and tossable.

[Sig_Fiend]

What is the purpose, need, or want? Is the idea to stick with one and get rid of the other?

If it has to be a choice between those two, go with the one with the Centurion rail. Better rail IMO since BCM's are still technically a form of a pinch lock.

If you're more flexible than just choosing between the two, here's another option. Since you mentioned the first has a Centurion quad rail, I'm assuming it's a C4, meaning you have a GI barrel nut. If so, you could swap out the rail for a Troy M-LOK. It's larger diameter, probably much more rigid, but more comfortable since it's not a quad rail. Those mount using the GI nut so it's a quick swap. I just did a similar swap (Centurion M-LOK 12" to Troy M-LOK 13") on a 6920-OEM2 upper and really like what I'm seeing so far.

[Bergeron]

While I prefer a lightweight-focused carbine, because they all get heavy when we bolt all of our goodies onto them, I'd rather trade my weight budget for weight in the barrel than weight in the rail.

The more optics on the rail, the more important rail stiffness becomes. Stiffness is not directly correlated with weight, but instead design, weight, and materials. In a similar vein, I'd like more barrel weight to be closer to the chamber, where it both does me more good in heat dissipation and in balance.

For my recent PCC, I went with a Faxon carbon fiber rail, and while I doubt the attachment method is the sturdiest compared to other systems, I'll be curious to see how/if it flexes with the light/laser combo I have on it. On the other hand, if I was going for a low-light, night-vision use gun, I hear many good things about the Geissele rails, from both an attachment method and stiffness perspective, and I'd probably pay the weight penalty for that heavier rail system.

I've got an upcoming 5.56 carbine that I'm planning on trying out with the JP heat sink system. While I get that most all JP stuff is intended more specifically for competition use, I want to see what a 14.5", .650" under the handguard profile barrel with a heat sink manages in terms of heat dissipation and total weight. That gun is getting a very lightweight MI Pic-Lok rail that weighs the same as the Faxon carbon fiber. We will see.