Geissele / Light Alum Rails Unreliable? Per Internet...

[Sanch]

I bought my first geissele rail, an MK16 rail this week and I liked it so much in hand, uninstalled, that I went to buy another but it was sold out from the one dealer who happened to have them 2 weeks ago in the size and color I wanted.

So I googled around more and found a trove of internet hatred for them, and not just them, but potentially any light free float alum rail system that hugs the barrel tightly. ]

Allegedly, the us military or someone did drop testing and when they dropped these URGI mk16 rails, the rails bent slightly, contacting the gas block which is really close to the inside of the rail, and changing point of impact by something ridiculous like 5 To 10 MOA.

Then apparently according to a Reddit summary of the issue, this was all over ARFcom 2 years ago and was wiped by moderators who, depending on your standpoint, were either trying to cover it up. Or they were getting d0xing/death threats from Bill geissele off their forum.

Personally I don’t put much stock in arfcom or Reddit, but it does seem very plausible a drop of the rifle could bend the rail every so slightly and cause it to press against the gas block, so internet rhetoric aside, before I buy a few more of these for different uppers I want to make sure it’s not an issue. By asking here, with reasonable common sense folks.

I’m wondering if I shouldn’t stick with a heavier and more durable 4-way pic rail setup for an upper I plan to run an IR laser on, since it seems like the issue is mostly related to devices attached to the rail itself. It wasn’t clear if an aimpoint on the upper receiver would be drastically have POI shift from this, versus a laser on the rail.

So maybe I put MK16 on a few uppers with no lasers and then some more heavy duty rail for the one upper with a laser (for night vision work)?

[Sanch]

One more thing, these threads I perused suggested a rail that had an opening over the gas block would be better since If the rail bent, it wouldn’t touch the gas block. I only recall seeing a single rail do that in my previous research, a noveske, designed to give access to their adjustable gas block.

But I’m wondering now, as maybe silly as it sounds, to take an MK16 and carefully cut an opening where the gas block is. I don’t need a full rail anyway on top of accessories. Maybe even cover it with a rubber rail cover that would be flexible and move if the rail bent and otherwise would push the gas block against the rail cover.

[theJanitor]

Mk4/8 are regarded as the better rails for lasers, and that’s what I run. I have three of them. The KAC URX rails are regarded as super sturdy for laser use too, and of course one is installed on my SR15

That’s being said, it’s pretty hard to bend a rail, and of course, the longer the rail, the more leverage to bend it.

[Wake27]

This was a huge deal, at least in the sense of how emotional people got over it. Seen lots of shit back and forth about it without more than some sketchy "proof" and testing. I think its very plausible that any light weight narrow tube of a rail may contact a gas block but in this argument, people seem to forget that the barrel flexes too. So pair a light and narrow MCMR/MK16/whatever with a barrel that is supposed to flex, a gas block that is unnecessarily large as it is in many cases (I love BCM but their .625 gb has the same OD as their .750 gb I'm pretty sure, G's old ones were apparently large as well), and a huge cantilevered weight (the ARFCOM thing came from a MAWL which may be cool but is a giant thing hanging off of one side) and yeah, chances are good that some shit will contact.

Whether all of that results in a dramatic POI shift for your setup may be entirely dependent on the sum of all factors, especially considering the wide variances you can have in an impact. But at the end of the day, do you expect your gun to take that hard of a hit, and at the same exact time, your only option is a laser or front sight in a two way shooting incident? When I get into NODs and lasers, they'll likely go on my URX4s but I'm very happy with my MCMRs and MK16s and want more of both. I do pair them with small gas blocks when possible but the only real justification I can see for significant concern is MIL usage and even then, there needs to be more data before anyone does anything. There was a big concern over the M855A1 round cracking uppers that was complete bullshit and came about this exact same way.

[WobblyPossum]

I heard some of this stuff when it was going around too but Army SF has been issuing the URG-I uppers with Mk16 rail for a while now. Have there been reports of these issues from field use or just these third hand reports from some initial testing?

[Eyesquared]

Not only are SF issuing the Mk16 upper, the 75th Ranger Regiment is also issuing them as well now. I'm going with another case of internet rumor blown out of proportion. I followed it all fairly closely at the time and there was a lot of speculation and people pretending to have inside knowledge about contracts being cancelled, etc. that never came to be. :rolleyes:

[Default.mp3]

Don't use a giant low profile gas block, and you'll be much less likely to impact the sides of the handguard (it's not a rail, guys); they were using MK12 gas blocks during the tests, IIRC, which barely fit under. Deflection is not just an issue of the rigidity of the handguard itself, but also how it interfaces with the barrel nut, how long the overall handguard itself is, etc., so a cheese grater isn't going to necessarily help much, despite all the extra material. I've also been told that a big issue was that there was relatively loose fit between the barrel nut and the handguard itself on the MK16s (at least for that batch back then), and when combined with the relatively soft aluminum barrel nut, impacts would permanently deform the barrel nut and cause shift; the fact that the legendary MK1s were made with 7075 barrel nuts, and so are the MK4s and MK8s, makes me think that 7075 barrel nuts are fine, as long as tolerances are properly held.

If you're so worried about all this shit, just get a monolithic upper and call it a day.

[Eyesquared]

In the ar15.com thread that got deleted, there was no evidence of any damage to a barrel nut. There was visible damage to the 12 o'clock rail on the handguard where the MAWL was mounted that would have accounted for the reported zero shift. I have never seen any proof that the barrel nut was somehow related to the 1 reported URGI incident. Based on the photo it seemed fairly obvious to me that the inside profile of handguard under the 12 o'clock rail has a stress riser and that the damage was due to the combination of that and the way the MAWL is attached. There were many rumors flying around about replacing the aluminum barrel nut with a steel one, which to my knowledge has not been substantiated.

I would also be hesitant to trust hearsay even from people who claim to have inside knowledge. At the time I talked to a lot of people who acted like they had inside knowledge about the URGI and in the end all their information was obviously publicly available in that one leaked powerpoint slide and the ar15.com thread. But none of them would outright come clean and say they were just going off stuff they saw on the internet.

Among other fun (unsubstantiated but often repeated) URGI rumors:
The real reason there was zero shift is because the offset placement of the bolts clamping the rail to the barrel nut results in less clamping force
The gas block is whipping around inside so hard it can destroy the rail from the inside (???)

[Sanch]

I do have a MAWL that I picked up recently, so I am concerned about this issue. I am planning to put together some new upper to use it with, so for now, it’s in the box.

I’m a bit concerned about the 13.5” Mk16 I picked up recently, intending to use with a 14.5” new barrel that has mid length gas tube. Because from my reading, speculation existed that mid length are more prone to this potential issue since the gas block is further from the receiver and thus a slight angled bent to the rail would contact a mid length gas block before it would a carbine one, based on trigonometry.

I do like this 13.5” MK16 and I’m not planning to put an IR laser on all of my uppers, just one of them. So maybe I use this MK16 for a different build, and I buy something like the Larue quad rail (4-way pic rail) to use with an upper for the MAWL? It will be a bit heavier but the MAWL gun is my zombie LARPing gun, not a “carry gently from the padded case to the firing line” gun.

I don’t love the MAWL but it seems like the best civilian IR laser on the market now. So I’m kind of stuck with the hand off the side thing until a better civie laser comes out.

I like lightweight pencil barrels in general so even if the rail is heavier, perhaps the weight will be offset by the lighter barrel. I do plan to run it with a mini 556 silencer, too, if that matters.

[Eyesquared]

I do have a MAWL that I picked up recently, so I am concerned about this issue. I am planning to put together some new upper to use it with, so for now, it’s in the box.

I’m a bit concerned about the 13.5” Mk16 I picked up recently, intending to use with a 14.5” new barrel that has mid length gas tube. Because from my reading, speculation existed that mid length are more prone to this potential issue since the gas block is further from the receiver and thus a slight angled bent to the rail would contact a mid length gas block before it would a carbine one, based on trigonometry.

I do like this 13.5” MK16 and I’m not planning to put an IR laser on all of my uppers, just one of them. So maybe I use this MK16 for a different build, and I buy something like the Larue quad rail (4-way pic rail) to use with an upper for the MAWL? It will be a bit heavier but the MAWL gun is my zombie LARPing gun, not a “carry gently from the padded case to the firing line” gun.

I don’t love the MAWL but it seems like the best civilian IR laser on the market now. So I’m kind of stuck with the hand off the side thing until a better civie laser comes out.

I like lightweight pencil barrels in general so even if the rail is heavier, perhaps the weight will be offset by the lighter barrel. I do plan to run it with a mini 556 silencer, too, if that matters.

I don't think the midlength or carbine gas is pertinent at all. I think the theory that the gas block is whipping around inside the rail and then destroying it from the inside is silly, and without even doing any math, it strains credulity given a basic understanding of vibrations. The barrel of an AR is stiff enough that even if it vibrates a bit when the gun is dropped, I am very skeptical that the gas block will get enough energy going to damage anything meaningfully. The issued configuration has midlength gas, too.

I would put the MAWL on the gun and try not to smash it into things but I would not be overly concerned. From looking at a friend's newer Mk16 it appears that Geissele has revised the extrusion die so that the corners under the 12 o'clock rail have a larger radius hence less of a stress riser. Either way, with the old or newer rails, the interior profile there is still as strong as many competitors' rails like the BCM, KAC, or even the DD RIS2. The cross section is also as strong as the Mk4/Mk8 that many people claim is good to go. The Larue rails are pretty overbuilt in this area if this is really a dealbreaker, but I'd just run it as is and if it breaks, make Geissele make it right.

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[Wake27]

I heard some of this stuff when it was going around too but Army SF has been issuing the URG-I uppers with Mk16 rail for a while now. Have there been reports of these issues from field use or just these third hand reports from some initial testing?

None that I'm aware of.


Not only are SF issuing the Mk16 upper, the 75th Ranger Regiment is also issuing them as well now. I'm going with another case of internet rumor blown out of proportion. I followed it all fairly closely at the time and there was a lot of speculation and people pretending to have inside knowledge about contracts being cancelled, etc. that never came to be. :rolleyes:

I hadn't heard Rangers picked them up, where did you get that info?


Don't use a giant low profile gas block, and you'll be much less likely to impact the sides of the handguard (it's not a rail, guys); they were using MK12 gas blocks during the tests, IIRC, which barely fit under. Deflection is not just an issue of the rigidity of the handguard itself, but also how it interfaces with the barrel nut, how long the overall handguard itself is, etc., so a cheese grater isn't going to necessarily help much, despite all the extra material. I've also been told that a big issue was that there was relatively loose fit between the barrel nut and the handguard itself on the MK16s (at least for that batch back then), and when combined with the relatively soft aluminum barrel nut, impacts would permanently deform the barrel nut and cause shift; the fact that the legendary MK1s were made with 7075 barrel nuts, and so are the MK4s and MK8s, makes me think that 7075 barrel nuts are fine, as long as tolerances are properly held.

If you're so worried about all this shit, just get a monolithic upper and call it a day.

They're literally called Super Modular Rails though.

[Default.mp3]

They're literally called Super Modular Rails though.Sure, and DD also calls them rails, etc. Doesn't mean they're right. I know, I know, prescriptivism is a lost cause, everyone knows what it means in context, and I'm just going to look like a pedantic asshole if I keep up this fight, but dammit, words have meaning.

[Eyesquared]

None that I'm aware of.



I hadn't heard Rangers picked them up, where did you get that info?



They're literally called Super Modular Rails though.

You can see the 75th Ranger Regiment URGIs in recent videos on their Facebook page. If you follow Pat Mac on Instagram you can also see them in the videos earlier this year when he was training 3/75.
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[M2CattleCo]

Geissele rails are so easy to change that I would just enjoy the MK16 as hard as you want and if you bend it unscrew 4 little bolts and pop a new one on.

I love Geissele rails, the MK14 is my favorite.

[pastaslinger]

I stopped buying Geissele products but more related to their quality level relative to their price point (imagine buying a colored but otherwise normal buffer tube for $80) and my very poor experience with their Black Friday sale when I was quoted a ship date of by 8 weeks, soared past 8 weeks, had my credit card charged up front, then got to see them give away the same uppers as I had bought at shot show to free. I was so upset by their poor business practice that I refunded through my credit card company, as did many others, rather than waiting even longer and getting a coupon that would've required me to buy more Geissele products to benefit from.

[theJanitor]

I’d be more worried about rail deflection when loading up pressure on the rail while using a laser. You can deflect a laser while loading up a vfg on a barricade, or loading up a bipod. Chuck had mentioned this in a recent Q&A session. Like I said, just look at the ribbing and construction of the mk4/8 compared to the mk16, which is just a tube.

I have a mk16 and a laser is going on that, so I’m not that worried. Just do some testing on your own, and know your own gun. My mk8 shows very little deflection under load. I haven’t tried the mk16

[theJanitor]

Sanch , looking back at your original post, I think you'd be much better off finding a factory assembled upper. If we're simultaneously talking about MAWL's, NV, bent rails, overgassing, and adjusting gas via depth of gas tube insertion, I think it's more critical that you just buy factory.

BCM has been very good at releasing various uppers, from 12.5-16" in all varieties. SOLGW has put out a ton of stuff, including the 13.7's. There are lots of ways to get a suitable upper for your needs. You obviously have the budget, buy a factory upper and get to actually using it, instead of worrying about it.

[JRB]

Perfect example of what I explain to folks as 'too much religion in equipment choice'.

Handguards and rail systems in particular seem to generate entirely too much excitement and 'religion' around a piece of fucking aluminum. Does it mount well? Does it hold all my shit? Are all the holes the correct shape for my preferred geardo theology? Is it reasonably priced? Is it actually available?
There's a LOT of rails on the market from a lot of good companies that check all those blocks, from brands that don't start with 'G'.

A name or brand is only as good as the customer service, otherwise it's just a piece of metal. If you're spending more money on it than a 'just the metal' price for it, you ought to get some good QC/QA and customer service to back that up. Otherwise just buy a cheap Brownells Wrenchman or MI free float and put more money in the barrel where it matters.

On that note, if your free float rail costs more than your barrel, you're building a stupid rifle.


Sanch , looking back at your original post, I think you'd be much better off finding a factory assembled upper. If we're simultaneously talking about MAWL's, NV, bent rails, overgassing, and adjusting gas via depth of gas tube insertion, I think it's more critical that you just buy factory.

BCM has been very good at releasing various uppers, from 12.5-16" in all varieties. SOLGW has put out a ton of stuff, including the 13.7's. There are lots of ways to get a suitable upper for your needs. You obviously have the budget, buy a factory upper and get to actually using it, instead of worrying about it.

^Wholeheartedly agreed. Buy a quality upper from a vetted, duty grade manufacturer like BCM, Sionics, Daniel Defense, etc and stop sniffing the proverbial corks on all this stuff.

[Calvin118]

I got a 16" super duty with a 15" mk 16 rail with the receiver integrated anti rotation tab in their Black Friday sale. This one came with the reduced size gas block. In order to test it's trustworthiness I dropped it 3x from six feet onto an old wood floor. It was dropped directly onto a scout 300 mini attached via arisaka inline mlok at the end of the rail. This would give the rail as much of a torque insult as it would ever see in my hands. It hit so hard that the pad on the end of the stock popped off all three times.

The result? No appreciable loss of rail mounted zero and no rail damage. Maybe the new smaller gas block made a difference? Maybe it was the receiver tab? No damage to the mlok slots either.

I still prefer the Mk 8. In side by side comparison it flexes less than any of the popular tube rails at a given length and the plus shape works with my big hands. But I would have enough confidence in the mk 16 they sent me.

[RAM Engineer]

I asked Ken Elmore to build me an upper a few years ago, and he stated that he would not use Geissele rails, and the only rails he currently (at the time) would use were Larue or rails that attach to a USGI OEM barrel nut. At the time, Larue didn't offer an MLok rail, but they have since rectified that, as long as you don't want an uninterrupted top rail.

[DDTSGM]

On that note, if your free float rail costs more than your barrel, you're building a stupid rifle.

Most honest thing posted on the internet today.

[Wiseup]

It is very simple, do not try and get your info from reddit or even here, it's just the same BS repeated over and over, by losers who read something from someone who heard that someone read something someone heard. Look at the people who have reputations for honest reviews, Or who actually own them, you will not find them talking about bendy or damaged rails. Geissele's SD (with that rail) has a very good rep to those who know or own. This is an old rumor that won't die. You are suckers if you listen to fools.

[Biggy]

UNDERSTANDING HANDGUARD FLEX AND POINT OF IMPACT SHIFT FOR LASER AIMING DEVICES
- A write up by Nocturnality

https://www.nocturnalitygear.com/resources/

[Default.mp3]

It is very simple, do not try and get your info from reddit or even here, it's just the same BS repeated over and over, by losers who read something from someone who heard that someone read something someone heard. Look at the people who have reputations for honest reviews, Or who actually own them, you will not find them talking about bendy or damaged rails. Geissele's SD (with that rail) has a very good rep to those who know or own. This is an old rumor that won't die. You are suckers if you listen to fools.>do not try and get your info from reddit or even here
>Or who actually own them, you will not find them talking about bendy or damaged rails

So... how do you read the reviews of folks that actually own them if you don't use social media or forums?

Geissele's had a lot of missteps in the past years, they no longer deserve to be trusted to be good to go based purely on reputation. I wouldn't steer people away from Geissele, but Geissele having issues wouldn't really surprise me, either.


UNDERSTANDING HANDGUARD FLEX AND POINT OF IMPACT SHIFT FOR LASER AIMING DEVICES
- A write up by Nocturnality

https://www.nocturnalitygear.com/resources/That test is pretty fucking terrible, IMO, and provides very little useful data. n = 1 for each handguard, we don't have any specs on how each upper was assembled, and the whole testing regime in general was fucking wack given it it relies on the skills of the shooter, the ammo, the ability (or lack thereof) to maintain consistent pressure, etc. Would be way easier with much less variables to simply just throw an upper in a vice, zero a laser at some distance, apply pressure to the handguard, and see how much the laser moves.

Beyond that, the deflection wasn't really the source of the kerfuffle with the MK16s, but the allegations of POA/POI shifts after impact.

[Casual Friday]

It is very simple, do not try and get your info from reddit or even here, it's just the same BS repeated over and over, by losers who read something from someone who heard that someone read something someone heard. Look at the people who have reputations for honest reviews, Or who actually own them, you will not find them talking about bendy or damaged rails. Geissele's SD (with that rail) has a very good rep to those who know or own. This is an old rumor that won't die. You are suckers if you listen to fools.

Welcome to PF.

[JRB]

It is very simple, do not try and get your info from reddit or even here, it's just the same BS repeated over and over, by losers who read something from someone who heard that someone read something someone heard. Look at the people who have reputations for honest reviews, Or who actually own them, you will not find them talking about bendy or damaged rails. Geissele's SD (with that rail) has a very good rep to those who know or own. This is an old rumor that won't die. You are suckers if you listen to fools.

Checking dates before responding to posts on established forums is a decent idea, too.

[SecondsCount]

It is very simple, do not try and get your info from reddit or even here, it's just the same BS repeated over and over, by losers who read something from someone who heard that someone read something someone heard. Look at the people who have reputations for honest reviews, Or who actually own them, you will not find them talking about bendy or damaged rails. Geissele's SD (with that rail) has a very good rep to those who know or own. This is an old rumor that won't die. You are suckers if you listen to fools.

Welcome to PF.

I try not to get caught up in these little contests but it would be nice if we had some real data from both sides to back up these discussions rather than he said, she said.

[Eyesquared]

Welcome to PF.

I try not to get caught up in these little contests but it would be nice if we had some real data from both sides to back up these discussions rather than he said, she said.

The real data is that all the claims about contracts being cancelled never came to be, and that the handguard can be seen in use when the Army releases pics of SF and 75th RR soldiers. The whole hullabaloo came from 1 broken handguard and everything online since has been highly speculative or outright falsehood.

This one is funny to me because when the ar15.com thread got deleted it became a game of telephone. I think if Geissele had left it up and simply addressed the issue in the thread it would have been a non-issue.

[call_me_ski]

The biggest problem the whole thing was Bill’s handling of it rather than any deficiency in the product.