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.


  1. Your main point, I totally agree with. The standardization of pic rail and the addition of it to the upper led to everything else listed. It fundamentally changed how we think about rifles, from a complete system you bought and just dealt with, to a foundation of a larger much more flexible system of gun, barrel, sights, ammo, lights, lasers, etc., etc., etc. The ending of the AWB allowing people to actually buy these things again, plus the GWOT motivating people to fully explore the AR’s potential only back up your position.

    What I don’t agree with is your dismissal of pistol braces. They aren’t in the top-5 advancements to the AR, but they revolutionized the entire SBR and ‘rifle’ pistol market. They are far from “Too idiotic to even address seriously”.

    Why do you think so little of them?

  2. best advancement was ‘perfection’ of the sub-systems.
    then rail.
    others not very noticeable…
    cheap stuff from PSA- i know nothing about, but do like better pricing on quality stuff!

    i regret the immense cost of the military’s efforts to REPLACE the best weapon we’ve ever had… including the constant shuffling of names and responsibilities!

    thanks for your site- i have learned a lot, and appreciate the info.


  3. The development and adoption of the M1913 rail is without a doubt the greatest innovation of the modern AR-15. The most significant changes evolved from there…..flat-top upper which helped usher in a revolution in optics themselves, railed forearms that spurred the development of the accessory market. Accessories have even helped change tactical and practical application of the AR-15. The modularity, compatibility and flexibility of M1913 rail and associated mounts completely revolutionized things.

  4. I still have a scope adapter for the carrying handle. It was the only option through Desert Storm to have optics on an M-16A2. As you all know, the challenge was having the optics sit so high offset of the bore axis.

    Yes, having a flat top receiver is the greatest advancement in the design. I was enlisted when the Army transitioned from the A1 to the A2. Faster rifling helped for accuracy out at 200-250-300 meters, but it was more of a refinement than an advancement. Having optics and BUIS available due to a flat top receive added a few hundred meters to the engagement range of the rifle and made marginal shooters much more likely to get a first round hit.

  5. I’m utterly mystified why one modification does not catch on. The reciprocating side charging handle attached to the bcg. This single part eliminates the awkward “T”charging handle in the rear, the forward assist assembly, and the shell deflector. Fewer parts to manufacture and easier to use.

    • because its simply not needed and its over rated. as it is thw AR15 charging handle is out of the way and ambi.

      “easier to use” is a very questionable claim. as is “out of the way”

    • When I discovered Knights Manufacturing hadn’t bothered to put the brass deflector on the SR-25, I declined to finalize my two rifle order. I was informed they were working on a fix, which turned out to be some chintzy piece that mounted on the rail. No thanks. The military also told them to F*** off with their rifle if they couldn’t even bother to design an up-to-date gun. THAT got their attention. Unfortunately, they decided to limit sales to the .gov at that point, and by the time they got caught up enough to sell to civilians, CA wouldn’t allow them to be sold here.

  6. I would absolutely dislike a reciprocating external item on the rifle. That would increase the potential for gear snags, weapon damage, etc. The weapon as it is now does not have any external moving parts. That is ideal in my opinion.

  7. Oh, of course “working-man’s” rifles are a bad thing from companies like PSA. Indeed, I long for the days when base-line AR-15s were $1,500 so only a few of us could afford them. Those peasants, don’t they know their place? Ridiculous how they think things like modern manufacturing methods and offering MPI testing on $50 BCGs are any replacement for the tireless toil of magic pixy fairies we had. Ghastly, I say.

    • Eh, I found my way here from Says Uncle, and I’m more for Cal’s point than against it.

      Cheap ARs are good. Competition is good.

      For people who aren’t competition shooters, I can’t see any reason to pay $1,500 for an AR.

      • some people prefer buying something that will truly last a life time of hard use. A lot of people shoot a lot more than they just build parts guns to post pictures of online. and they want something that will hold up to it not something that just looks like the one that will last a life time. it is your money to spend on how you want. a hobbie look a like gun or a gun you think you may have to use to protect your life.. competition use has little to do with it

  8. Definitely the standardization of the Picatinny rail. A flat top AR upper is certainly nothing new but before they were either one-offs, totally custom from a specialty shop or in the case of the later Canadian rifles not generally obtainable by the masses to offer widespread acceptance. Once the flat tops were available the AR went from just an “open sighted Army rifle” to a really versatile shooter. Think anything from a Mk18 to a Mk12 and everything in between.

  9. I have no problems with PSA and their offerings. I bought 2 of my rifle kits from them, AR15 5.56 NATO Freedom 16″ barrel rifle kit and their PA10 .308 18″ barrel rifle kit. Their barrels are sourced from FN USA in West Columbia.

  10. You nailed it, Shawn. On all points. Turning the AR15 into a commodity product is not good for the platform or industry long-term. The AR15 platform is now the most generic of any firearm in history, with almost full interchangeability of parts, the only real difference being base material and manufacturing quality. Hipster-minded owners now gravitate towards two extremes…one being the cheapest possible, “just as good as” rifle, and the other a “BRO!-ed out” super billet boutique rifle. In the middle lives the tried and true, and largely ignored in the current market, proper milspec-spirited, TDP-driven, quality carbine with common sense attachments. Buy wisely.


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