Equipment Reviews Geissele Learning To Shoot Mk16 Mlok Tech The Rifle

Rethinking Rails: Cutting it Too Close


Trendy free float rails are actually slimming down. I’ve some considerations. I’ve actually come full circle for my thought course of on tremendous skinny modular rails and my conclusions usually are not re-assuring. As AR equipment have progressed, we’ve moved in the direction of ergonomics and modularity. We’ve lengthened free float rails and slimmed them down. Warfighters want room for grips, lights, and lasers so it’s comprehensible that shooters need the actual property. Properly… What we now have finished is created an extended, skinny, skeletonized beam and weighed it down on the finish. Is that this the method for sturdiness? Learn on:

Enter the Ongoing URG-I Fiasco: AKA #Railgate

Take this with a grain of salt till we obtain some extra clarification from the army, however the next appeared on a Fb URG-1 group web page. A consumer posted a spliced PPT picture from an unknown slide collection which claims to point out the Geissele rail struggling injury throughout drop testing: 

“Throughout testing the rail when dropped shifted 10+ moa whereas a m4 solely noticed three moa. Supply is a pp presentation the military put collectively. Anyone have something on this?”  Consumer MadMax 1611 – Geissele rail scuttlebutt

This military PPT presentation lacks context. We don’t know the specifics of the data, and maybe it’s illegitimate. Because of the above slide and people exact same questions, a number of Mk16 house owners on determined to place the difficulty to mattress by performing their very own quite simple drop exams. The outcomes?  

Let’s check out some consumer posted footage of their rails submit drop:

Word this customers prime rail seems barely bent. – Pictures from Geissele rail scuttle butt

The inside of the rail can also be displaying fuel block injury:

Picture from Geissele rail scuttlebutt

The consumer revealed that the fuel block made contact with the rail inflicting vital inside deformation and lack of MAWL zero together with his drop check. The check was then repeated with a model new rail and one other consumer recording the check:


So we’ve a number of instances with the URG-1 deforming upon impression (with mawl hooked up) in response to these customers on Within the above video, the fuel block once more contacted the internal rail and seems to trigger some injury. Now would these rails fail with no MAWL? That’s what we don’t know. My guess is just not. The added weight of those laser aiming units little question play a task within the deformation as they merely add weight to the top of the beam and exacerbate the flexion upon impression. The MAWL weights 10ouncesby itself! So are  trendy skinny and thin free float rails sturdy sufficient to deal with these units?

Free Float or… Don’t?

Geissele is well-respected and makes “bombproof” merchandise. Invoice notes that the Mk16 was designed to satisfy the client’s specs. We’ve many rails from quite a lot of MFG’s which might be outwardly just like the Mk16 and have loads of MLOK slots on each side. I feel they might meet the identical destiny. I feel the lesson is that longer, skinnier rails usually will probably be weaker than the thicker, shorter quad rails of the previous. Working example:


The M4 KAC RAS confirmed much less deflection within the PPT slide. Why? I feel its merely stronger by design. The KAC RAS attaches to the hand-guard cap and delta ring meeting. It isn’t free-floating. Because of this the main help buildings of the rail are the rail itself *AND* the barrel. Collectively they type a extra sturdy construction than the Mk16. Can any free float rail examine to the power of a quad rail meeting wrapped round a M4 SOCOM barrel? I’m starting to have my doubts.

Seems the previous warhorse KAC RAS nonetheless has some recreation these days.

I’ve had these considerations for a while, however I didn’t have actually sufficient knowledge or examples to make a convincing argument. I started to write down about my considerations in July with my DMR article. With these points rearing their head on the MK16, I feel I’ve some examples for my argument. Many different skinny rail designs might endure the very same destiny when dropped. In case your laser and BUIS are not capable of maintain zero because of influence then we might contemplate that rail a no-go. Minimal fuel block clearance, lengthy skinny beam with lights and lasers on the finish… It’s a zero shift ready to occur! These points from influence are of concern sufficient, however take into consideration this as nicely: the barrel whip of thin barrels may also trigger a rail to contact the fuel block. This will probably be exacerbated by MID LENGTH fuel methods.  This will likely result in inconsistent accuracy.



Lengthy, skinny, skeletonized, and weak with very slender clearance of the fuel block doesn’t a confidence encourage.

There are a number of failure situations with a thin free float rail:

  • Rail is bent: Lack of BUIS and IR system zero
  • Rail is bent and in touch with fuel block: Lack of BUIS, IR system, and Main Optic zero.
  • Rail isn’t bent, however barrel whip causes the fuel block to make contact with the rail, leading to inconsistent accuracy/ accuracy loss.

These situations weren’t a wide-spread situation with older free float methods. I’ve been right here a very long time. I first bought an AR in 2002 and have been obsessed ever since. Return a number of years in your thoughts. Take into consideration our previous quad rails with plenty of inner clearance, thick partitions, and extra weight. (Ugh, I don’t miss the load!) Now flip over to the fashionable period the place we’re equipping  longer, skinnier, narrower, skeletonized methods with little or no clearance between the fuel block and rail. Which one will tolerate impression higher? I assumed so too.

So how can we get round this? I’ve a number of ideas:

Answer 1: Select a rail size which permits the fuel block to stay uncovered.

Aero Precision M5E1 (5)

Aero Precision M5E1 with uncovered fuel block. Impacts in need of a tank operating over this technique wont trigger the rail and fuel block to make contact. Gotta hold ’em separated. Hey HEeey wait. No. I’ll cease.

That is an apparent answer for the tremendous slim rails. Along with eradicating the tight clearance points, the shorter rails may even be stiffer. The fashionable rails pushing 15 inches are much less stiff than their 12, 9, 7 inch (and so forth) counterparts. It’s simply leverage. The longer the rail, the extra leverage the aluminum should resist to make sure it doesn’t bend. Shortening the rail and exposing the fuel block stiffens the rail and ensures the fuel block performs no half in damaging the inside of the rail.

Aero Precision Builders Set M4E1 Atlas S-One (20)

I discovered the Aero Precision Atlas S-One to be tremendous slim and ergonomic, however the clearance is so tight under the provided fuel block that MLOK equipment contact the fuel block when put in. The 2 rail slots underneath the barrel are unusable apart from rail panels.

Not fearful about impacts? What occurs for those who mount a bipod on the finish of a 15 inch rail? Is the bipod load inflicting your rail or MLOK equipment to contact the fuel block? There goes your main optic’s zero as now your rail has utilized strain to your previously “free floated” barrel. Some fuel block and rail combos are so tight that hand strain on the barrel may cause it to contact the rail!

What should you drop your rifle and the rail is now contacting the fuel block? Bye bye main optic zero. Bye bye BUIS zero because it’s now canted with the rail. This isn’t a superb state of affairs.

Answer 2: Select a rail with a bigger I.D.

Although these rails can nonetheless shift on influence, if the clearance between the fuel block and rail is giant sufficient then it’s one variable that may be eradicated. Your BUIS could also be tweaked, however your main optic will stay un-affected. In case you MUST disguise your fuel block beneath the rail, get a rail with extra, and never much less, clearance across the fuel block.

Larue 12.0

Old fashioned rails won’t be high-speed… however good previous quads might actually be stronger than M-Lok merely because of the additional materials of the picatinny rail. I don’t personal the above rail anymore as a result of it stopped being excessive velocity! Don’t I really feel dumb.

What’s my most popular setup? My most popular setup is a A body entrance sight outdoors the rail. Nonetheless. Name me old style, however the injury to the rail wont throw off my entrance sight OR my optic.

Wrapping Up:

The impetus for writing this text is to air my considerations relating to tremendous slim / tremendous skinny rails. I consider my considerations to be legitimate for all skinny rail methods and we should always concentrate on rail size, fuel block clearance, and concentrate on the impact of heavy equipment on the finish of an extended rail. One drop and your gear is out of alignment. BUMMER.

From right here, I hope our collective information continues to enhance. I hope I’ve opened some eyes relating to this current development in the direction of modular, skinny, lengthy free float rails. Typically its good to take a step again and look at gear from outdoors the you-tube bubble. We purchase these things for sport, however we acknowledge it may be utilized in emergencies as properly. We hope we by no means have to fret about our optics dropping zero in a life or dying state of affairs… but a number of thousand miles away there are people who depend upon the power of their gear to remain within the struggle. Our collective ardour (and dollars spent!) for the black rifle has helped usher in an period of R&D unmatched by some other weapon in existence. As a group, we should additionally acknowledge that there are limitations and lifeless ends… even when these lifeless ends are common and enthusiastically acquired.

So far as the Geissele Mk16, massive G has promised to deal with any clients who’re having a problem with the drop testing after the vacations. Excellent news that G takes care of consumers. The large query is what number of different producer’s lengthy and thin designs would endure the identical failures? I’m betting an entire bunch. 

Remember, hold your rifle prepared, your powder dry, and construct them to be prepared for something.

Lothaen OUT!


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