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KeyMod vs M-LOK

M-LOK Left, KeyMod right

We were asked, “What are the pros and cons of M-Lok vs Keymod?”

Long ago there was no standard for attaching stuff to firearms. We use sling studs, bayonet lugs, hose clamps, bespoke custom mounts, etc.

Then came the MIL-STD-1913 Picatinny rail. And all was well. It took some time for people to move away from the weaver rail, but eventually most of the world adopted the 1913 rail. Except for Zee Germans, who as always thought they could do better. They came up with their own spec for rails, where they took the surface most likely to get damaged in use and make that the critical dimension. Thus the NATO spec rail was born.

Then people wanted smaller and slicker hand guards. Companies started milling off the rail section and offering bolt on rail sections. But each company had their own system. While the bolt spacing was somewhat standardized due to the sizing of Picatinny rail, how the rail section interfaced was not standardized. KAC, LMT, Larue, Colt, etc all had their own various rail attachments for their slick handguard.

VLTOR designed a new mounting system in 2012. Somewhat similar to the old post and slot system used in shelving, they included a taper on the mounting tab and recoil lugs. Best part is that they released the design as open source, so any company could use it for free.

Noveske and Bravo Company were early adopters and helped popularize the system. It looked like it was going to be the next standard. But then something interesting happened.

Before we get to what happened, lets talk about the other option, M-LOK.

Magpul came up with a new mounting system on their Masada and their early MOE line of accessories. They had slots cut(or molded) into the hand guards allowing accessories to be bolted to the slots. This was 2009. But this MOE slots sucked. They were inconsistent, and the backside of the slot had to be accessed to install an accessory.

In 2014, Magpul came up with a new standard, the M-LOK. M-LOK used slots where the accessory would lock in using a rotating T-Nut. M-LOK is free licensed, not open source like KeyMod. So people can made it freely, but they have to get permission from Magpul. This way Magpul ensures people don’t deviate from spec.

Wow, writing the history there took longer than I thought this article would be.

So what are the cons:

KeyMod accessories can be installed wrong. When I first mounted a KeyMod QD swivel, the next day I read about people mounting Keymod accessories backwards. I said, “How could anyone mount one of these backwards?” Then I found out that I mounted mine backwards. Doh.

Also some companies are cutting corners and making KeyMod accessories out of spec. Either missing the critical taper on the lugs, or missing recoil lugs.

As for M-LOK. M-LOK accessories protrude into the rail, so in areas with little clearances they can be an issue. Or sometimes the screws can protrude enough to touch a barrel in a narrow free float tube.

M-LOK screws protruding past the hand guard

It looked like KeyMod was winning the modular handguard war. Many were pushing it as the superior mounting system and it looked like the Army was going to adopt it for use on newer hand guards and sniper rifles.

Then we get to the interesting test. NSWC-Crane did a test between the two. They deemed M-LOK as being better.


Overall, test and evaluation demonstrated that the M-LOKTM modular rail system surpassed the performance results achieved by other modular rail systems. In repeatability testing, M-LOKTM allowed for the repeated installation of the same accessory rail in the same location on a handguard with an average point of aim (POA) shift of 1.3 MOA, as low as one quarter the average POA shift observed by other modular rail systems. Drop test results demonstrated that M-LOKTM systems maintain securement of accessories to the handguard and sustain less damage from impact forces than some other modular rail systems. Failure load testing demonstrated that M-LOKTM systems support the highest load of all modular rail systems tested. In fact, the test equipment used to interface with 1913 accessory rails secured with the respective modular rail system across testing repeatedly failed prior to failure of the M-LOKTM attachment system. Even so, testing of the M-LOKTM systems failed at loads as high as over three times the maximum failure load of some other modular rail systems. NSWC Crane recommended to USSOCOM that the M-LOKTM modular rail system be utilized over the alternative systems tested. USSOCOM has chosen to incorporate the M-LOKTM modular rail system in acquisition efforts including the Suppressed Upper Receiver Group (SURG) and Advanced Sniper Rifle (ASR).

Since this test, interest in KeyMod has been reduced, but it is far from dead. M-LOK is gaining much more popularity.

M-LOK design of just being simple slots has allowed M-LOK mounting slots to be added to a great deal of accessories for other older firearms. Newer gun designs are able to have thin aluminum hand guards with simple slots milled in them allowing for the end user to add what ever accessories they deem fit.

Both are good, but now the consensus is that M-LOK is better.

Greatest innovation to happen to the modern AR-15 and it’s variants?

Over on arfcom yesterday I ran across a thread with a poll asking members what they thought the biggest advancement has been for AR15s. The thread poster then gave a list of choices for readers to vote on. See above. Sadly most of the option were eye roll inducing or not really even worth mentioning. It did get me thinking about the subject though which is rare for something posted on arfcom GD.

First I want to talk about the choices.

1.Red dot sight. While the use of durable, reliable and simple red dot sights have been a great leap forward in helping average dude with hitting it had to have something else that facillitate that. ore on this later.

2. The accessory rail. Primarily this would be the Knights Armament RIS/RAS. Yes there was other but the KAC rails for the M4/M16 was what really kicked it off because it was the rail the military went with. This allowed for a now unlimited variety of force multiplier to be attached to the rifle. A great contender for the number one spot in my opinion and a good argument could be made that it is. But like the first choice something had to come before.

3.Piston. No. An unneeded “advancement” Colt already developed in the 60s that solved a problem that doesn’t really exist.

4. Too idiotic to even address seriously

5. Polymer magazines like the Pmag, Lancer etc. An advancement to be sure. Have we all given up on USGI spec aluminum though? I don’t know anyone that has. Would the AR be less if they never come along? I don’t think so. I think they fall some where with the red dot sights but I would like to hear your opinion on this one.

5. The arrival of the used car salesman equivalent of gun companies. Is this an advancement? I would submit to you this is actually something that is hurting things. More than one first rate Mfg. has told me that PSA and their like are causing them to offer more and more cheap shit models with cost cutting measures to compete. You may view this as a good thing but I don’t think a world of mainly DPMS “sportical” ARs being sold by every company other than the boutique makers as a good thing.

Now. What do I think is the greatest advance for the AR15? The “flattop” upper receiver and the development of the M1913 rail of course. It wasn’t the first of its kind of course, but it was the one the US standardized and adopted. There was attempted at weaver type rails and the Canadians had a version but once Dick Swan and Colt came up with the current rail everything changed. Slowly at first but then like a snowball rolling down hill. The rail led to being able to mount optics lower. This lead to the Ar15 being better developed for precision use for more than just service rifle competition. The 1913 standard helped with the handguard rails like the KAC and on and on and on. Yeah yeah, the MLOK and KEYMOD and whatever MOD are a big thing now, but not on the top of the receiver it ain’t. The flatop upper has doubled the modularity of the AR15 maybe tripled it or more.

A couple of other factors that spurred development in a big way. 1. The 1994 AWB and its end 2. the GWOT. These two aren’t changes to the gun itself from a technical or mechanical standpoint but they sure did speed that up. I think I will leave that for another day or Howard can tackle that if he wants to add to this.

Some smaller things that I think advanced the system in increments. The change over to the then not all that popular but now very useful 1/7 twist and related ammo that followed . At first we got the arguable smaller step up to the 62 grain M855. Meh. Then we got the 69, then 77grain and now 80 and 85 grain bullets. The outstanding accuracy and lethality of the heavier rounds can not be ignored. Of course the ammo was developed for competition at first then as a more accurate round for the MK12 which came about because of the ability to mount optics to the flat top upper.

While not an AR15 but something related, companies finally working out the kinks to get us reliable, durable and accurate SR25 pattern 7.62MM ARs. People forget that while the Stoner SR25 and the “armalite ” ( read eagle arms) AR10 had been around for a while, it wasn’t really until about 09 that we started to see 762 rifles and carbines that you could shoot at a high round count schedule like an M4, be reliable and accurate. And now we have most of them using the SR25 pattern magazine like God and Eugene intended. But that’s a talk for another day.

I’d really like to hear some thoughts and comments about this. What do you think was the biggest advancement. Please don’t count the AR15 itself because of course it was. Some discussion on this would be much appreciated .

If you want to read what the expurts had to say on arfcom. Link below. Though you can save yourself the trouble if you saw the poll image screen shot above on how they voted. Some posters offered up much better possibilities than the original posters nearly joke like selection though.


Inland MFG M3 Carbine

We have seen a few really nifty M1 carbines out of Inland the last few years. It was just a matter of time before they offered us the version the least known or seen. The M3 was the variant done up to mount a huge active IR night vision “sniper” scope and a huge battery to run it. It didn’t really pan out at the time but it’s existence did mean the carbine Colt version of the M16 would forever be known as the M4.

Now, if you add some normal day time optic to the handy little carbine that is another story. Above you can see the base/ring mounting system Inland has developed for the mounting of optics. Simply put, the base uses the redfield/leupold turn in front ring and dual windage screw rear ring system. any rings you want to buy that work in this manner will fit and work. And it works really well. I chose to put a vintage Weaver K4 on the gun as it is more evocative of the time period this gun had its short heyday.

The machine work Inland put in on this is kinda of amazing. My friend and partner in crime when it comes to our more insane long range shooting ideas is an experienced machinist and when I showed it to him, we both at first thought the base was part of the receiver and machined into shape. It took a surefire light and a closer look to see that it was indeed not part of the gun. It really is a beautiful job.

One of the things that sticks out on the M3 was the cone flash suppressor. Inland did not forget this iconic attachment. And it is attachable. As you can see above it is a simple system. You can chose to put it on or leave it off. I found it did not really impact accuracy any amount I could determine while on and shooting at ranges the 30 carbine round was meant for. There was slight changes when shooting with our without though and depending on the mood or whichever gun you may have, the amount of re-zeroing could vary. I did not bother to re adjust the optic as it was less than 3/4 inch impact change and I was shooting for groups and location on the target did not matter to me.

As expected, being able to use some magnification helped with group size at longer ranges. The Inland M1s have been accurate for me over years since starting to test them.

Group above was shot off bags from bench at 100 yards. The group is a 10 round group and the one flyer I offer no excuse for other than I just touched it off without being ready. The group below was fired at the head at 150 yards.

All groups were fired using federal soft point LEO ammo. I have no idea where I ever got this ammo from but it is pretty accurate. Unfortunately I used all I had left for this test. Target below was fired at center body of target from 300 yards. With the optic it was pretty easy. It is still a carbine meant for combat but I can’t imagine anyone with any sense really having much to complain about its performance at this range. But I am sure some one will in the comments.

Hey, what more could you ask for considering the limitations of the round? Pair the optic with a Korean era 30 round magazine and you got one heck of a neat little carbine for something. Walking around the farm shooting ground hogs or maybe short range coyote gun. With proper bullet selection maybe even white tail at shorter ranges. I don’t know, your imagination is the limit. It doesn’t need justification if you want it. if you think it’s neat then buy one. The quality won’t let you down, nor it’s looks.

I apologize for not having a full glamour shot of the gun with optic for this review. Something went badly wrong with my camera during the uploading process. The camera decided to die after 9 years and it took the remaining pictures with it. This includes the rest of the groups shots and the glamour shots of the gun posed with period militaria collectibles and all that crap you are used to seeing when I do these. That is also why this review seems shorter than normal. It’s not just your imagination or my laziness. I have been trying to recover those photos and if so I will update this review ASAP. To add to that this was the first time I didn’t bother to back up every picture by taking the same pictures with my Iphone just in case.

Update On Your’s Truly & When Guns Are Outlawed, Only Outlaws Will Have Superglue

I thought I would check in today in case some one, some where in some cave some where that has been wondering about me.    I am unfortunately  still in the process of trying to get myself back to normal.  Long story short. I have a lot of digestive  problems.  Have since I was 17.   Used a medication that worked great for years.  Then it didn’t. Doc started new medicine.  Takes a long time to get that new stuff working. I will spare everyone the less than pleasant details.  Take my word when I tell you that it is exhausting and even writing this took an act of sheer willp0wer.    But I am not gonna die or nothing, much to the disappointment of The Old M14 Boys Club. I’m sure.    I am feeling a bit better every day though at least.    Once I am back I have a few things  that everyone may look forward to.  Inland sent me the T3 carbine for review.  That is the m1 carbine in its Korea war era trim but with a scope base on the receiver which I have mounted a period correct-ish or at least correct-ish looking, weaver 4x to it and It’s pretty nifty.    Also still got the Colt Trooper carbine with MLK rail  that I will  do a test and review.   Non-gun related are a couple of hand made custom knives from Black Wolf Knives that I am pretty sure any knife people will want one or two after seeing them.    I will hopefully be back to daily posting within a few more weeks but until  then I will try to pop in a couple time a week.    Sorry for the delay and I appreciate your patience.


Johnnie Lee Carter courtesy: Odessa Police

“ODESSA, Texas – Authorities have arrested a fugitive Texas father who allegedly beat his 1-year-old daughter and used glue to seal her eyes and mouth.”


You know those mugs they make that says something like “Wold’s Greatest Dad” ?  They most decidedly did not make them with this guy in mind.


“Johnnie Lee Carter, 29, was arrested Monday in El Paso on a felony charge of injury to a child causing serious bodily injury, according to the Odessa Police Dept.

Carter – who fled after police were called to a domestic incident Sept. 16 – choked and punched the little girl before applying super glue to her face, the child’s mother told police.

The woman told investigators that Carter beat the infant because she wouldn’t stop crying…”

There are just some things you see on this world that you almost have a physical reaction to   not unlike how you would react when food poison kicks in.




Springfield Rifles: What’s the Difference?

I will be killing to  stones with one bird today with this repost from weaponsman.com.   Today is a post Kevin wrote about sprinfield M1903s.  I decided to share this  today as the 03  has been an ongoing topic over the last month, I have no idea how we got stuck on it lately but we have.   

Today we have the weekly re-share of a weaponsman.com post. We share these posts to honor our friend Kevin O’Brien who died early last year. Kevin was known as “Hognose” by his many friends and admirers and  post his work here in an effort to save his work and honor him in our own way.

Springfield Rifles: What’s the Difference?

The US model 1903 Springfield rifle was made in five major versions. New entrents to collecting American martial arms sometimes struggle to tell these very similar rifles apart, but actually it’s pretty easy. Here’s a Springfield cheat sheet to take with you to the fun show:

From GlobalSecurity.org. Note that the stock on the A3 is more commonly like the one shown on the A1.

From GlobalSecurity.org. Note that the stock on the A3 is more commonly like the one shown on the A1.


  • The US Rifle Model 1903 was originally made for the M1 Cal. .30-03 cartridge, and service rifles were rechambered to the improved .30-06. There were metallurgical problems with early serial number receivers and bolts, and firearms under number 800,000 from Springfield Armory and 286,596 from Rock Island Arsenal should not be fired, because those are the numbers beyond which improved heat treating methods are known to have resolved this problem. (The bolts aren’t numbered, but any bolt that has a handle “swept back” rather than bent at 90º to the bolt axis is good to go).
    This is the business end of an early (pre-1905) rod bayonet Springfield.

    This is the business end of an early (pre-1905) rod bayonet Springfield.

    A few very early models had rod bayonets, and these were mostly converted to Model 1905 16″ knife bayonets after 1905 (at the insistence, we’ve noted, of Theodore Roosevelt) so they’re extremely rare. The rear sight was a ladder sight that went through several iterations, mounted forward of the front receiver ring. It could be used as an open tangent sight or raised and elevated for volley fire to ranges of almost 3,000 yards. A variant of the 03 called the US Rifle M1903 Mark I was adapted for use with the Pedersen device. Most of these were made in 1918-1919 and they wound up issued as ordinary 1903s. They are not especially rare, but make good conversation pieces. Another rare variant (illustrated) used the Warner & Swasey telescope commonly fitted to the Benet-Mercié “automatic rifle” — it had a terrible time holding zero, but that’s what American snipers had Over There.

The rifle lasted decades more, but the sight didn't.

The rifle lasted decades more, but the sight didn’t.

  • US Rifle Model 1903A1 is identical to the 1903, except for the stock, which has a pistol grip.
  • US Rifle Model 1903A2 is another extreme rarity: a Springfield altered to be a subcaliber device for conducting direct-fire training on various artillery weapons on small arms ranges. The stock, handguards, sights were removed and the gun could be fitted into a 37 mm sleeve for use in a 37mm gun, or the 37mm adapter could in turn be fitted in a larger-caliber adapter for 75mm, 105mm or 8 inch (203mm) artillery. They were generally made from 1903s and will have the “A2″ notation hand stamped after the 1903 on the receiver ring. A brass bushing on the muzzle, just under an inch (0.994”) in diameter, adapted the bare barreled action to the adapter. A few have the A2 electro-penciled in place, it would take a Springfield expert to tell you if that’s authentic (the example Brophy shows is stamped). Most of the A2s were converted back into ordinary rifles, surplused, or scrapped at the end of the war as the Army had abandoned subcaliber artillery training.


  • US Rifle Model 1903A3 is a wartime, cost-reduced version of the 1903A1. Remington had been tooling up to make the 1903, not for the US, but in .303 for the British. WIth American reentry into the war, Remington converted back to making a simplified 1903. The A3 reverts to the straight (no pistol grip) stock, uses a stamped trigger guard, and has a ramp-mounted peep sight like the one on the M1 Carbine. This sight is simpler than the Rube Goldberg arrangement on the 1903, and actually has greater accuracy potential thanks to around 7″ greater sight radius. It is the version most commonly found on the market, and was carried by soldiers in the first months of the Pacific War, and by Marines for longer. Until a working grenade launcher was developed for the M1 and issued in late 1943, an Army rifle squad armed with M1s still had one or two grenadiers armed with M1903A3s and grenade launchers. By D-Day, most combat units had the M1 launchers. Remington (and Smith-Corona) produced 1903A3s from 1941 to February, 1944.

M1903A3 sight

  • US Rifle Model 1903A4 is a 1903A3 fitted with a Weaver 330C or Lyman Alaskan 2 ½ Power optical sight. The Weaver sight is 11 inches long and adds a half-pound to the weight of the rifle, bringing it to a still very manageable 9.7 pounds. The Lyman is a tenth of an inch shorter and a 0.2 pounds heavier (the Lyman was very rare in service compared to the Weaver). Both have an eye relief of about 3 to 5 inches. Very late in the war, the M1C came into service, but the 1903A4 was the Army’s primary sniper rifle throughout the war. Note that several vendors have made replicas of the M1903A4, some of which (like Gibbs Rifle Company’s) are clearly marked. All 1903A4s were made by Remington.

There you have it — the main variants of the Springfield Rifle in a short and digestible format


About WeaponsMan

WeaponsMan is a blog about weapons. Primarily ground combat weapons, primarily small arms and man-portable crew-served weapons. The site owner is a former Special Forces weapons man (MOS 18B, before the 18 series, 11B with Skill Qualification Indicator of S), and you can expect any guest columnists to be similarly qualified.