Recommend Mlok FF handguards for laser use

henschman

Newbie
I'm contemplating getting on the Mlok train with a new build, and possibly retrofitting some of my existing setups that currently have KMRs. I've heard of guys having issues with IR laser POI shift with some free float handguards, and was hoping y'all could point me in the direction of some quality options that don't have this issue.
 

tmoore

Member
ive been using the BCM MCMR and love it. its nice and slim for a good grip on the rail and also no shortage of mounting solutions as the mlok points are at the 12, 1, 3, 4, 6, 8. 9. and 11(o-clock) positions. If your buying a known quality product zero shift would be hard to achieve as long as your not slamming the gun on stuff. but than again i dont know what your using the rifle for so i guess its hard to say you are not doing just that.
 

Frosty_Bear

Regular Member
USASOC, U.S. Army Special Operations Command just went with the Geissele rail. You can find the same URGI upper on Brownells. There are plans to to sell the rails separately, but they're churning out as many as they can for the Army and police forces rn because of the huge demand.

http://soldiersystems.net/2017/05/0...keymod-vs-m-lok-test-conducted-at-nswc-crane/

This is a very good article detailing Crane's work on Picatinny vs. Keymod vs. Mlok. Basically, Mlok itself works great for almost everything. Picatinny is still better though, just at a weight cost(hence USASOC going for a full top picatinny for lasers). It's the lock up near the reciever that matters. There are different versions out there, but the Geissele set up is "generally" regarded as being the strongest.

https://geissele.com/super-modular-rail-mk14.html
(mlok on the 3, 6, 9)
https://geissele.com/super-modular-rail-mk8-m-lok.html
(mlok on all quarters except top)

They have very similar lock up measures to the USASOC/URGI rail, but they don't have the anti-tilt lugs that lock up with the upper receiver. Which is honestly, probably overkill for most civilians. There rails are still generating a massive amount of force on the barrel nut to remain in place.
 

chasnojm

Regular Member
Besides the mentioned rails above. The Hodge "wedge-lock" design by SOLGW, ZEV, FN and TRIARC would be more than capable. Lets be realistic here, BCM MCMR rails are more than capable to host lasers. Some rails are better than others. I think in the current environment and for a fighting rifle, most quality rails are capable of providing a mount for laser for the 0-300 range fight. I'd say beyond 200, PID is difficult with NVGs. Specifically with BCM, the first run of the KMR rails were quite soft in comparison to the current production.

We've been killing people with PEQ15/16s on KAC drop in rails for a while. Is it ideal? Not anymore, but it still works.
 

David Mayeur

Regular Member
Besides the mentioned rails above. The Hodge "wedge-lock" design by SOLGW, ZEV, FN and TRIARC would be more than capable. Lets be realistic here, BCM MCMR rails are more than capable to host lasers. Some rails are better than others. I think in the current environment and for a fighting rifle, most quality rails are capable of providing a mount for laser for the 0-300 range fight. I'd say beyond 200, PID is difficult with NVGs. Specifically with BCM, the first run of the KMR rails were quite soft in comparison to the current production.

We've been killing people with PEQ15/16s on KAC drop in rails for a while. Is it ideal? Not anymore, but it still works.

For clarification, the Wedge Lock was a joint venture between Hodge and MEGA. ZEV bought out MEGA and retains part of those rights. The Hodge Wedge Lock is made from 7075 and has a Titanium barrel nut. The ZEV version is 6061 and has a Steel barrel nut. SOLGW's current version is 6061, but they are planning to make a 7075 version as well.

IIRC, Mike at SOLGW has mentioned that the Wedge Lock is stronger than the Geissele SMR handguards. I don't think you can go wrong with Geissele, Hodge's Wedge Lock, or anything from KAC. If I was concerned with zero shift on a laser, I would NOT recommend using a BCM KMR type handguard or any other slim type handguards. I would default to the user's purpose. Using lasers out to 50 yards is a lot different than using them at greater distances. As you've stated, the MCMR is capable, it just wouldn't be my 'personal' first choice for that application.
 

chasnojm

Regular Member
For clarification, the Wedge Lock was a joint venture between Hodge and MEGA. ZEV bought out MEGA and retains part of those rights. The Hodge Wedge Lock is made from 7075 and has a Titanium barrel nut. The ZEV version is 6061 and has a Steel barrel nut. SOLGW's current version is 6061, but they are planning to make a 7075 version as well.

IIRC, Mike at SOLGW has mentioned that the Wedge Lock is stronger than the Geissele SMR handguards. I don't think you can go wrong with Geissele, Hodge's Wedge Lock, or anything from KAC. If I was concerned with zero shift on a laser, I would NOT recommend using a BCM KMR type handguard or any other slim type handguards. I would default to the user's purpose. Using lasers out to 50 yards is a lot different than using them at greater distances. As you've stated, the MCMR is capable, it just wouldn't be my 'personal' first choice for that application.

Geissele is 6061 T6. I'd be pretty surprised if the other ventures with 6061 T6 rails and steel barrelnuts with Wedgelok aren't just as capable. Not to mention Hodge Pinch lock is 6061 T6 with a steel barrel nut and was developed to be a "stupid strong rail". While 7075 is stronger, I think we are splitting hairs.
 

pointblank4445

Established
Geissele is 6061 T6. I'd be pretty surprised if the other ventures with 6061 T6 rails and steel barrelnuts with Wedgelok aren't just as capable. Not to mention Hodge Pinch lock is 6061 T6 with a steel barrel nut and was developed to be a "stupid strong rail". While 7075 is stronger, I think we are splitting hairs.

Re: 6061 vs 7075...look at the construction of the early SMR's like the Mk 1, 2, 3 and the PLok (especially at the 6 o'clock)...they are thick has hell and could be used to beat a man to death and the comparison goes out the window. In the context of thinner designs it might matter. That aside, I'm looking at the barrel nut more than anything if rigidity/accuracy are a top priority....HK/Geissele or Pinch/Wedge lock (no matter steel or Ti) is how I've been rolling. Surface area of the barrel nut matters as does attachment in order to pevent the rail slipping and not returning to rest/zero in the same place when torque is applied. Curiously enough, the guns with those rails across the board respond better to mild bipod load/pressure than other designs (including but not limted to DD and KAC).

Will other stuff work?...sure. Though I think that kinda goes against the spirit of this institution and the ability to get into and exploit the minutiae of things.
 

David Mayeur

Regular Member
Design, thickness, and length all play a part in the ability to resist deflection.

Tubes in general are more resistant to deflection.
The shorter the tube, the less deflection.
The thicker the tube, the less deflection.

The difference between 6061 and 7075 may mean the difference between a handguard that is .125" thick versus one that is .090" thick. There is a weight savings to be had. It may be splitting hairs, but it may also matter to some.
 

chasnojm

Regular Member
I feel like we are saying its a compromise of capability for the sake of saving a buck. I'm not saying unknown parts "are good enough/works for me", but realistic employment of a shoulder fired rifle/laser at distances, under NVDs, I'd say more is going to be affecting that (such as beam divergence) versus just deflection.

I think for the sake of education, we should setup rifles with the same barrel + laser with the different rails and see how much force applied it takes to cause a deflection.

I'd really like to be able to quantify how much "better" one rail does over another. That way someone could make an intelligent decision to choose strength and inevitably weight for less deflection vs lighter and possibly cost. Please, don't confuse me with some idea that I'm advocating bullshit brands.

Funny, we all agree on the best options, granted Hodge isn't really easy to attain and might not be an option at all due to availability. KAC is hard to get hold of as well and SMR MK1,2,3 aren't any more produced either.
 

user12358

Regular Member
Deflection isn't the biggest problem as most shooting under NODs isnt done with serious load applied to the rail. The problem is the ability to return to zero after the deflection occurs, whether it be from loading a sling or bipod or from the rail receiving impact.

Also 7075 has almost double the yield strength of 6061 which is certainly not just splitting hairs. You are looking at something in the neighborhood of 72kpsi vs 40 kpsi, 6061 is just much easier to machine.
 

chasnojm

Regular Member
Deflection isn't the biggest problem as most shooting under NODs isnt done with serious load applied to the rail. The problem is the ability to return to zero after the deflection occurs, whether it be from loading a sling or bipod or from the rail receiving impact.

Also 7075 has almost double the yield strength of 6061 which is certainly not just splitting hairs. You are looking at something in the neighborhood of 72kpsi vs 40 kpsi, 6061 is just much easier to machine.

Thank you. That's the kind of difference I want to know about. I'm still curious of how much (insert the way to quantify) this affects 6061 rails. And to be clear, how much deflection under "Combat" or "Duty" use is applied to rails. Can a 6061 rail be sufficient to prevent permanent deflection or is 7075 the only way? If you go sledge hammer style on a dude with your rifle, I'd expect stuff to get bent, no question there.
 

BooneGA

Moderator
Staff member
Moderator
WARLORD
USASOC, U.S. Army Special Operations Command just went with the Geissele rail. You can find the same URGI upper on Brownells. There are plans to to sell the rails separately, but they're churning out as many as they can for the Army and police forces rn because of the huge demand.

http://soldiersystems.net/2017/05/0...keymod-vs-m-lok-test-conducted-at-nswc-crane/

This is a very good article detailing Crane's work on Picatinny vs. Keymod vs. Mlok. Basically, Mlok itself works great for almost everything. Picatinny is still better though, just at a weight cost(hence USASOC going for a full top picatinny for lasers). It's the lock up near the reciever that matters. There are different versions out there, but the Geissele set up is "generally" regarded as being the strongest.

https://geissele.com/super-modular-rail-mk14.html
(mlok on the 3, 6, 9)
https://geissele.com/super-modular-rail-mk8-m-lok.html
(mlok on all quarters except top)

They have very similar lock up measures to the USASOC/URGI rail, but they don't have the anti-tilt lugs that lock up with the upper receiver. Which is honestly, probably overkill for most civilians. There rails are still generating a massive amount of force on the barrel nut to remain in place.

There has been enough negative press about the URGI and its rail issues that I would hesitate to recommend them pending additional testing.

Rick
 

user12358

Regular Member
Thank you. That's the kind of difference I want to know about. I'm still curious of how much (insert the way to quantify) this affects 6061 rails. And to be clear, how much deflection under "Combat" or "Duty" use is applied to rails. Can a 6061 rail be sufficient to prevent permanent deflection or is 7075 the only way? If you go sledge hammer style on a dude with your rifle, I'd expect stuff to get bent, no question there.

This has been done privately by a number of different organizations but I am unaware of any publicly available studies. It is people that have seen these private studies that are saying Geissele, Hodge, and KAC. I'll also throw in the LMT monolithic uppers even though they technically aren't rails.

What this comes down to in its most simplified form is a single side anchored deflection problem. This can be tested by adding a force at difference lengths along a rail that is attached to a statically anchored upper. The considerations to look at are how far the rail deflects for a given load (important to know for true deflection of a laser from things like slings and bipod being loaded) and how the rail returns to zero (important for retention of laser zero over repeated deflections).

Basically for anyone that doesn't have experience with the four options being discussed, the classic free float rail that we are talking about is broken into two pieces, a rail and a barrel nut. The more contact between these two, the better off we are for being able to get as close as possible to the true material spec for yield because it becomes more and more like a idea single anchor beam deflection problem. The three best solutions to this problem have been the very long and sturdy barrel nuts like from the SMR and WedgeLock/PinchLock family of rails, making the rail and barrel nut one piece like the Knights rail, and making the rail part of the upper receiver like the LMT MRP uppers. Once you have a solid barrel nut lock up you begin to look at both the geometry and material of the rail in regards to resisting and returning from deflection. This is where 7075-T6 has a significant advantage over 6061.

As far as how much this effects the real world. You can see deflection down range when loading a bipod or a sling hard. This is why you want to have the RAPTAR mounted up by the scope and not on the rail and why people will move their sling back by the receiver when using an IR laser. You can also move the IR laser further back towards the receiver to minimize the effects of deflection.

Can 6061 be sufficent? Absolutely, with enough material and a short enough rail. There are also many other considerations in a upper receiver package like the inner diameter of the rail and the length of the gas system and gas block design which, if not properly clearanced can hit the rail and can cause forces to be applied on the inside of the rail. This is the issue that has been talked about with the MK16 and the URG-I which I believe the original post is alluding to.
 

Default.mp3

Established
I keep hearing this, but WHAT is the actual issue(s) with the URGI/Mk16 rail?
Zero shift during impact/drop testing. The MK12 gas blocks impinging on the handguard, how soft the aluminum is for the barrel nut, and the loose barrel nut to handguard interface are supposedly the contribution factors to this issue, according to the rumors.

Griffin Armament makes the LoPro RIGID, which they claim also has minimal deflection by design, would be curious to see how it actually does. Hodge has also said that DD makes handguards with minimal deflection (besides Geissele and KAC), though he did not specify which product line.
 
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