AR Handguards and Forends

[farscott]

I am literally overwhelmed by the number of choices available for handguards and forends for the AR. I only have experience with a few, including the standard two-piece, the Noveske 11.5" Switchblock rail, and the PRI Gen III round free-float. Of those, I like the PRI the best due to the free-float nature and how cool the tube stays during firing.

Here is what I think a rail should do in order of priority from highest to lowest.

1) Protect the gas block and gas tube from impact and not be dislodged due to usual rifle usage. This drives the minimum length. I do like the longer rails as they are more flexible for field-improvised rests as well as providing longer sight radii.
2) Provide grasping surfaces that are friendly to the bare hand.
3) Facilitate the dissipation of heat from the barrel without burning hands.
4) Allow the rifle to be shot from a rest without changing impact due to pressure on the barrel.
5) Provide means of attaching lights and sights.
6) Not be any heavier than needed. The corollary to this is that the rail not need covers to make it hand friendly.

So what rails and forends are people using? How do you decide?

[voodoo_man]

Geissele.

Accept no substitutes

[Jay Cunningham]

So what rails and forends are people using? How do you decide?

What is the purpose of the gun it's going on? What do I need the rail to do to support the mission of the gun? How much am I willing to spend?

[farscott]

What is the purpose of the gun it's going on? What do I need the rail to do to support the mission of the gun? How much am I willing to spend?

Good questions that should drive the process, but even those do not reduce the solution space to a few choices. I think there are more questions to be asked and answered to make an informed decision.

For the sake of this exercise, let's assume the gun is a general-purpose AR, used for training classes, informal plinking, and HD. All shots are well under 200 yards. The rifle needs to wear an Aimpoint, a sling, a set of BUIS, and a light. Budget is not an issue.

There are a ton of choices out there, and I do not see an objective way to make an informed decision.

[ASH556]

From an armorer's perspective, I pay attention to install requirements, accessory attachment methods, and security after installation. There are several rails/forends that I will not use or recommend because they have inherent design flaws. For Instance, the pre-G3 MI handguards only pinched the barrel nut and were prone to simply sliding off the front. YHM's threaded jam-nut design will rotate.

I prefer handguards that do not require the barrel nut to be indexed as too often, torque issues are encountered. Thus, anything that uses a GI barrel nut (Troy/Vtac, Centurion non-CMR) or the Noveske NSR.

The KMR is nice and light, but in my opinion more fragile than I'd like on a fighting gun. Then again, I like MLOK over Keymod because I feel like Keymod is too easy to screw up. Hard to know if it's the KMR's fault or the Keymod's fault, but either way, you see a lot of screw-ups with that combo.

Bottom line based on the criteria above, Geissele Mlok or Daniel Defense for Picatinny Quad-type. If you want to run it slick, then an ALG EMR or the Centurion CMR are excellent.

[SamuelBLong]

I will also tell you to go with geissele. They are very comfortable in hand, and they are the most sturdy rail out there.

I'm in the process of changing out all my guns to use geissele rails because of the stability.

I've used the KMR, DD's Slim Rail, DD Quad Rails, and various others.

Geissele has them all beat when it comes to eliminating rail / handguard flex. This is especially important as I'm using PEQ-15's and DBAL's, but it equally applies to running an iron sight way out at the end of a 13-15" rail.



Sent from my iPhone using Tapatalk

[Calvin118]

I have used the Geissele Mk 4/8, Daniel Defense and Centurion Quad rails, Noveske NSR, Troy Alpha, KMR, and others. What is "best" depends on your goals.

I have a couple KMR's on builds which are meant to be light weight, use an Aimpoint as a primary sight, and only have a pistol light mounted at 12:00. I do not use VFG's and the keymod holes are only used for a QD sling attachment and heat panels. The weight savings is noticeable.

An Aimpoint Micro in a quality mount is quite durable and will hold zero through a significant amount of abuse. I have some on range guns that are still going strong on the original battery after six years, and the shelf life of lithium-ion spare batteries is 12-15 years. I have accidentally dropped a H1 onto concrete hard enough where the tabs on top of the adjustment cap were completely crushed and the threads were deformed and zero did not move. Larry Vickers did a lot worse things to one during the DD test and that Aimpoint held zero as well.

On these guns the BUIS are there in the unlikely event that the sight goes down. Given the durability of the sight and the ease of changing batteries (or swapping a new Aimpoint) I would not expect to have to use them for very long. I use Magpul Pro BUIS on my KMR's and they hold zero fine through everyday bumps and drops. Granted, if you run a KMR over with a large truck at high speed or use it to pound railroad spikes you will probably put a dent in it. As long as your gas block is appropriately attached the 12:00 Picatinny rail would probably not deform enough where you would be unable to readjust to zero based upon your Aimpoint. Hopefully this would not happen often.

Some people have been concerned about the flex in the KMR. The KMR definitely does flex. If I cowitness BUIS through the Aimpoint and pull horizontally as hard as I can, I can easily move the front sight post completely off the Aimpoint dot. During normal firing positions (including with a sling and prone) applying normal amounts of pressure, however, this is not an issue and the co-witness does not change at all. At least that is my experience. I have also attached an ATPIAL-C to a KMR hunt hogs at night, zero'd it by matching the visible laser to the Aimpoint at 50 yards, and everything worked quite well. Can I move the laser if I apply full gorilla horizontal force? Sure. But again, it does not seem to be an issue with ordinary firing.

That said, the Geissele is extremely sturdy. I cannot change the co-witness at all even with my greatest horizontal force, and I imagine that folded Magpul Pro BUIS would hold zero quite well even if it was run over by a truck. If I was in a situation where I might have to depend upon my BUIS for long periods of time without a co-witness cross-check, or maintaining the zero on an IR laser over a prolonged period was a matter of life and death, then the Geissele would be my choice.

The NSR is somewhere in the middle. It is heavier (11oz total for 13") but definitely flexes less than the KMR. The long barrel nut may have a lot to do with this.

[SLG]

Based on your initial list, there are many good choices.

How do you want to attach the sling? Where and how do you want to attach the light? What does "hand friendly" mean? No gloves, or just minimal sharp edges?

Depending on those answers, I might recommend the G3 MI that I am currently trying out. Or the Geissele. Or the KMR. Or the Centurian (heavyish). Or the ALG.

You like the PRI. Why not that one?

[CoGT3]

Check out slrrifleworks. Multiple lengths, KMR/Mlok, multiple different profiles from heavier to lighter.

[farscott]

Based on your initial list, there are many good choices.

How do you want to attach the sling? Where and how do you want to attach the light? What does "hand friendly" mean? No gloves, or just minimal sharp edges?

Depending on those answers, I might recommend the G3 MI that I am currently trying out. Or the Geissele. Or the KMR. Or the Centurian (heavyish). Or the ALG.

You like the PRI. Why not that one?

Gonna answer a lot of posts using the quoted post because it asks a lot of good questions. I also appreciate the input from others, especially on the Geissele and KMR. My personal gut thought is I want nothing to do with the KMR based on issues with mounting, the weight when fabricated from Al 6061-T6, how it looks to feel in the hand (may be wrong as I have no experience), and the comments above.

For me, hand-friendly means no gloves, I can not tear up my hands sliding them on the rail, and I do not have to worry about burning my hands. The 15" version of the PRI forend is definitely being considered based on my experience with the rifle-length version so far. I really like how it feels in the hand, and that I can add rails only where I want rails. That way weight can be controlled while the forend is still very resistant to deflection and exhibits minimal heat rise. Right now, the rifle with the PRI has no iron sights, so not sure how the forend works with iron sights. I love how light the complete rifle is with the PRI forend without any rails.

I really do not have enough AR experience to express a preference on sling mounts. I am still experimenting with the sling on the PRI forend.

I want the light to be mounted on the right side of the forend as I shoot the rifle off my left shoulder as I am left-eye dominant. That may change as I shoot the rifle and learn what works and what does not.