I've noticed an increase in questions about why there are so many differences and lack of compatibility in the AR10 market.  I compiled a brief list of the main rifles and designs that have emerged since 1955, and some explanation as to why there are so many different designs.  As you can see, it is only going to get more complicated and difficult for DIY types who like to build.

1955-1962

* Original Armalite AR10 from the 1950's, to include Dutch, Sudanese, Portuguese rifles, many of which were imported back into the US, a few as complete rifles, and others as parts kits.  More of a collector's market.





1993

* Knight's SR-25, designed in conjunction with Gene Stoner himself. Introduced in 1993, using commonality with existing AR15 parts for ease, the SR25 entered into the market.  The biggest difference between the SR25 and original AR10's is the BCG, which has a narrower tail so it can be used with AR15 diameter RE tubes.  The fire control group is also patterned after the AR15, which has some distinctions from the original coil sprung AR10 hammer.





1996
* Eagle Arms (who acquired the Armalite name) EA-10 and AR-10's, with modified M14 mags.  Karl Lewis of LMT and David Dorbeck did much of the work on the Eagle Arms/Armalite AR10, using an SR25 upper receiver for a test bed.  Introduced during the time of the Clinton AWB, they had to source surplus magazines, since new mags could not be manufactured for civilian use, unless they were limited to 10rd or less capacity.   Armalite History





2001

American Spirit Arms approached the AR10 market with a unique left side, non-reciprocating charge handle design, using the new Armalite M14 magazine feed.



2003-2006

* Bushmaster introduced a Rock River licensed design in 2004, called the BAR-10.  It ran on FAL mags, but was discontinued in 2005, only to be revived as the RRA LAR-8 a few years later.



* DPMS, saw the demand in the market, and introduced an economy LR-308 rifle series in 2004 right before the sunset of the Clinton AWB, using a BCG and magazine patterned off the SR25, but a different set of cheap 6000 series receivers that don't work with the SR25.  The original magazines were of a translucent color, polymer, and limited to 10rd capacity, which was fine with the 24" bull barrel LR-308 rifle.  With the AWB sunset, the .308 AR market started to rapidly expand around this design, with several C Products sources as an OEM manufacturer for DPMS magazines.



* CMMG began offering receivers that were compatible with DPMS receivers, as well as some marginal G3 magazine compatible uppers and lowers that saw limited interest from the market.



* DPMS introduced the AP4, with a lower height 1913 rail on the upper, ejection port door, and FA/brass deflector, causing the growing handguard after market to have to diversify even more from Armalite vs. DPMS upper receiver thread patterns by accommodating the new rail height.  This carbine won the NRA's Golden Bullseye Award of the year.



2007-2008

* Fulton Armory began offering their FAR-10, using what appeared to be a lot of DPMS components, but with higher standards of QC, fit, and finish, using high end Krieger and Criterion barrels.



* Rock River Arms introduced the LAR-8, using FAL mags, a much longer receiver set, longer BCG, longer charge handle, and unique barrel nut threads that were seen on the Bushmaster BAR-10.  They changed the charge handle to a traditional latch design, but retained the ambi bolt catch and FAL magazine compatibility.



* JP Enterprises began manufacturing the LRP-07, starting with their own billet receiver set, bolt carrier, and DPMS bolts.



Noveske introduced their own AR10 line, with the striking project Leonidas carbine.



* Patriot Ordnance Factory added the P308 to their line-up, using different pin lengths and dimensions with their uppers/lowers, and their op-rod system design from the POF-15.



2009

* LMT expanded their modular rifle line to include a new 7.62x51 MWS, which later won the contract for the British L129A1 DM system.  Karl Lewis's background in the industry spans decades of AR15/M16/AR10 component manufacturing, engineering, and collaborative effort with other major names in the AR15 and AR10 market.  The monolithic upper receiver design taken from the AR15 MRP offers continuous rail, and also has a quick barrel change system representing significant advancements in the AR15/AR10 market that set LMT apart from the competition.  Other innovative features are found in the gas system, as well as the bolt, which uses dual ejector springs for increased reliability and spring longevity.



* Iron Ridge Arms began making billet receiver sets based on the SR25/DPMS BCG, which evolved into the IRA-X .308 rifle.



* LWRC introduced the op-rod driven 7.62 NATO REPR with proprietary receivers, handguard, and BCG.



* Mega Machine introduced the MA-10 with their own billet set as a foundation, but relying on DPMS or Armalite BCG/barrel compatibility, and DPMS/KAC upper receiver thread/barrel nut interface.



* H&K Introduced the HK417 & MR762, which are op-rod driven 7.62 NATO rifles using all unique H&K components throughout the guns.



* LaRue introduced the OBR 7.62 as an entirely new approach to upper receiver and handguard interface, eliminating any contact between the barrel nut and handguard.  LaRue also spec'd out his own magazine, BCG, and gas system optimized for Surefire Suppressor use.  The OBR also has a continuous 12 o'clock rail to mitigate mounting of optics, clip-on Thermal Weapon Sights, and other devices based on a lot of input from military customers in the SOF community.  The new PredatOBR represents a series of innovative features, including tool less handguard removal.




2010-2013

* Colt introduced the Colt 901-16S Modular system with .308 upper receiver group.  This rifle will accept a standard AR15 upper, with a mag well insert so it can convert from 7.62 NATO to 5.56 NATO.



* GA Precision introduced the GAP-10, based on POF/Hogue receivers/Handguard, with high end Bartlein barrel.



* Remington introduced the R-25 (this is really a Freedom Group Consortium DPMS receiver set, BCG, and Remington barrel) To differentiate from the AP4, these have a lightening cut on the integral 1913 rail on the upper receiver.  They were also introduced in .243 Winchester and 7mm-08.



* Bushmaster, under Freedom Group ownership, introduced the .308 ORC, using DPMS-type receivers and BCG, with a Bushmaster chrome lined barrel.



Ruger introduced the SR-762, op-rod driven 7.62 AR10.



Primary Weapons Systems introduced the PWS MK2 series, using a long-stroke piston arrangement.



* Smith & Wesson introduced the M&P-10, with totally divergent bolt and barrel extension geometry.



* Sig Introduced the SiG-716.



* Christensen Arms introduced their own receiver set, and production guns with carbon fiber wrapped barrels.



* Windham Weaponry (the former Bushmaster) introduced the SRC308.



* F&D Defense FD308, with innovative gas system, side charge handle, unique handguard.



2014
* Freedom Group introduced the GII through the "DPMS" brand name.  This is the most revolutionary development in the AR10 market since its introduction in 1955, in my opinion.



* Lancer introduced a revolutionary L-30 .308 rifle, incorporating many features reducing weight, offering modular magazine well, and an extended 1913 top rail.



* Seekins Precision introduced the SP10 .308, with some of the finest machining, fit, feel, and lightening cuts on the receivers.



* Aero Precision is now offering their own complete rifles:



* PSA has introduced their own receiver set.



As of just this week, we became aware of Wilson Combat's 308 Project:



The highlighted companies have maintained a specific standard for them internally, without much regard for compatibility outside of their area of control.  There never is going to be standardization in the AR10 market.

LRRPF52, once again, thanks for your willingness to share your extensive background and for the energy you spend on the posts.

Where there are several places to get history and technology backgrounds for the M-16 and AR15s, the same is more difficult for the .308 variety.

Thanks again.

Excellent post, my man. This oughta be tacked.

I would also like to add that since the initial offerings from KAC and Armalite in the 1993-1996 period, they have continuously added new models and innovation over the past 2 decades.  Examples include:

KAC Mk.11 Mod 0 SR25.  These were used by SF, JSOC, SEALs, Ranger Regiment, and some other SOF units, laying the groundwork for the later adoption of the Army and Marines' new SASS rifles.





KAC M110 US Army SASS Rifle



KAC M110K1 SASS Carbine



KAC SR25 ECC 7.62 NATO Enhanced Combat Carbine




Armalite AR10 SASS



Armalite AR10A, which is SR25 magazine compatible








LMT has also upgraded the MWS by lightening it with the LM8.



Rock River Arms has responded to the demand for lighter guns, with the LAR8 X-Series.

Cool stuff. Thank you for putting this together

Nice job, and I always enjoy your expertise in any thread...other than when you try to undermine the AR10 and descendants by trying to get everyone to switch to 6.5 Grendel.

Yes very cool. Someone should do this for 5.56 too

Superb Report, LRRPF52!

To which, this ol' AR-10'er buff would humbly add ---  The American Spirit Arms .308, with non-reciprocating side charger, circa 2001:

Nice.


I don't think I put this much effort into my grad thesis.  I'm such a slacker....

Good basic info.

USMC snipers also had some MK.11 Mod 0's while I was in Iraq back in 2008.



 

I knew I was missing something, and I remember the ASA well.  I was actually looking at ASA as an option before I bought my first AR10.

I have also updated the OP to include the Noveske Leonidas.

You might want to include a pic of the Hesse/Blackthorne HAR-25, if only as a warning to others on how not to do it.  

ETA:  Also, from 2013


Ruger SR-762


Best,
JBR

What about the Cobb MCR from the 2001 time frame, which was later bought by Bushmaster before being shelved? I know they weren't in production long. It's been a long time since I've seen one and I don't remember if it was larger than most AR10 type receivers or not. The swappable magwell seemed to be very innovative at the time.

awesome write up!  Thanks!

I updated the list with some of the ones that slipped by me, but I remember them all.  Cobb wasn't really a production gun-more of a prototype that Bushmaster and Freedom Group shelved after they bought them out.

I added the PWS MK2 and Ruger SR-762.  What I really need to sit down and do is make "The Chart" for all these production AR10's.  The problem is, even within a 1-3yr period on many of them, there have been design changes to address issues that were encountered with what turned out to be beta testing by customers with the first production runs.

We saw that with several iterations and mods to the Armalite AR10/M14 mags.

We saw that with the early smoke/polymer DPMS LR308 mags, 19rd mags, CProducts mags versions 1-?

We're seeing it with the PMAGs.  We're seeing it with bolt face depth variation across the board.  We're seeing incompatibility with certain BCG's and certain billet lowers.  There are different length gas tubes for the Armalite vs. DPMS DI guns in both the RLGS and MLGS, as well as different ILGS lengths out there.

The companies that are smart take magazine dimensions and control in-house, like KAC, LMT, and LaRue have done, since they can't control what Cproducts, ASC, or Magpul are doing, and how much loose tuning those magazine manufacturers have to do in attempts to make their mags work with such a wide variation of tolerances in the market.  That's a big problem when you look at it in that context.

Great post. Looking at what's available now I feel like I got in to the AR-10 game about 10 years too early.

I was playing around with the balance of a Colt 901 last night, and realized that they are one of the only companies in a good position to answer the weight and balance advantages of the GII, without having to change much.

If they offer a lightweight handguard model, or better yet, one with a modular handguard option with extended 1913 top rail like Lancer, but with carbine, mid length, rifle length handguard attachments, that would be competitive with the GII.  Look at their 7.62 NATO BCG in the above pics.  It is shorter than SR25 based BCG's.

It currently weighs 9.4lbs with the LE901-16S model.  A pound could be shaved off that handguard.  A pencil barrel could get rid of maybe 8 oz.

Get rid of the forward malfunction assist and shave some more weight.  I think they could hit 7.25lbs easily with a 16" gun, and balance it out since their receivers and BCG are shorter.

Cobb certainly did, in fact, produce and deliver guns to paying customers. They were not "production guns" in the same sense as an Armalite, but rather guns that were built and delivered upon special orders, sort of like RRA used to do with the LAR-15 series. They were in the marketplace for sure, not just one-off prototypes.



It's your thread, your rules, but I think ignoring that firearm does a disservice to the knowledge base. One of these days someone is going to make something similar and people will act like it's the hottest thing since sliced bread.



"There is nothing new under the sun."



 

I remember the Cobb very well, and will include it.  Was it 2004 when it was introduced?  I seem to remember it around that time.  Similar approach MGI used with the modular magazine well, but Cobb took it to another level with large frame uppers available for long and XL action cartridges.

We had a shooter bring an MCR-400 one year to the Boomershoot, it was really nicely made. Jewelry. Only one I ever saw in person

I must have missed that one.  What year?  I've been at BoomerShoot every year since 2010 as a coach/instructor for the Precision Rifle Clinic.  BoomerShoot is a very fun and friendly event that I don't plan on missing.  Great times every year.

The F&D Defense .308 AR10. Looks like it is still being produced.

2006 or 2007. Guy was a co-worker who quit to follow his dreams in either the Army or Navy.

Thanks for all you do at the clinic, we have people that come to take that class and don't sign up for the main event. It's clear where the draw is. If you see me running around say howdy, I'm usually standing too close to explosives or trying to set Monte on fire.

(pictures of the MCR400 from Firearms World) (I'll take the pictures out if you like, since it's a side fed 338 not a bottom fed 308)

Someone needs to do that in 7.62x39 that takes AK mags and drops on an AR-15 lower.

You've put in some time compiling the info, good on you, this is top notch stuff. As always seems KAC/LMT have the best rifles going out there

Buying one platform sure limits options.

Dad has an AR-10 from Armalite lower of the 1990's era, shot out the barrel and is looking for a new upper, he sold the entire upper :(.  I keep telling him a 260 from Armalite might be the best, but he would like a light weight 308.  CMMG advised the barrel nut is more of the change vs a Barrel for different versions.

To bad he is stuck with the M14 mags, Pmags have a good following.

AR10s are still moving forward!!

Thanks for the thread.

I still like the Armalite style mags. They are very well made. I still think more receivers should be made for this mag. Nothing against Armalite, but their receivers are boring looking. Plus I don't like cats.

There is nothing wrong with options, I think if everyone agreed on an upper receiver thread pitch, and just offered the 2 different mag styles, life would be good.

Does the GII Bull have an Aluminum gasblock?

Good stuff.  I have a late model Eagle (Armalite) AR-10 Carbine.  I love it.








 

I think it does. The one I saw looked to be aluminum. When I visited the DPMS distributor at the Knob Creek Gun Range Machine Gun Shoot, they had a ton of aluminum gas blocks for sale.

I think it is pretty much standard fare for DPMS. It is after all a $1500 or less DPMS, and not a $2800+ high end rifle.

Think of it as not paying $75+ for a gas block that may or may not suit your needs or wants, and leaving you with $70 or so to get the one you do want. That's how I look at it.

I figured it was. Just getting an idea of the final cost to get it how I want it.

LOL. I'm doing the same thing.


Of course, now that I think about it, replies such as ours should not be in this thread, as they really do not follow the original intent, and I know the OP devoted a considerable amount of time to this thread.

Thanks for taking the time to post  all of that great information.

Excellent chronology.

Great post.  You might consider putting the LWRC REPR in there, too.

It's in the OP.

I have the LAR-8 Predator HP, and it's 1 pound lighter than the X-Series, so how can that be a "lighter" gun? The LAR-8 X series is listed at 9.5pounds, the Predator HP, 8.6Pounds.

http://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_id=402

As far as the different "AR-10s" available, I find it interesting the money charged by some of these companies [DPMS, S&W, Remington, etc] and the lack of a quality product. Guys talk about 1.5" groups, replacing triggers, changing buffers and springs, function issues, etc. If I was paying $1500 for an AR like the DPMS, S&W, etc and I had issues with the gun, I'd be really P.Oed. I have had exactly zero issues with my LAR-8 and it shoots groups that you wouldn't believe, the barrel doesn't foul, and the trigger is excellent, and I didn't pay anymore for it than the DPMS or S&W sell for.

I actually think Rock River is in a unique position in this market, outside of the obvious one that their design is the most non-compatible with everything else.

If they were willing to wipe the table clean, and use one of their main distinctive features, they could really bite back into the AR10 market in a big way with economy volume sales per their normal distribution and sales model.  The existing LAR-8 design is not going to do that for them no matter how you slice it though with that awkwardly long receiver and BCG design, which is there because of the accommodation they made for the mag catch mechanism for FAL mags.

Thanks for the write up. Very interesting to see the evolution and disparity in the market.

But, the receiver is needed to work with the longer FAL mags. That also allows you to load longer ammo.

In all reality if they would offer more chamberings like the 260, 358, 6.5creedomore, 6.5 Lapua, 6x47, etc, they would really start to take market share. At one time they offered a 243 and 7-08 upper but I don't see it listed anymore. I don't know if that was because of the demand for 5.56 and 308 guns or what. My brother has a 243 Lar-8 predator and it will shoot just about any ammo well under 1 inch and it is 100% reliable too. The only downside is due to cartridge geometry or something else, the FAL mags won't work with the 243. The RRA poly mags are needed.

Different chambering are not their problem.  The design is.  When it was introduced as the BAR-10, it answered the Clinton AWB 10rd mag capacity limitation, but that ended within a year of the BAR-10's introduction, making it obsolete overnight.  The FAL mag is the problem, no longer the solution. Loading long COL only applies to a very small segment of customers, a % of reloaders, who are a small % of buyers, and there are several steel and poly mags for the SR25 mag compatible designs that allow longer COL loading.

RRA could respond to the market, and introduce something really cool, using two of the design aspects from the LAR-8 (not the receiver/BCG length and FAL mag compatibility).  I understand that this takes significant resources, but it makes the most sense in the current market.

Looks like Aero Precision is offering complete rifles as well:




Updated in the OP.

Nice looking rifle, but WHY do they have a malfunction assist?

I'm don't understand where the receiver, BCG, or Mags are the problem? With all the problems I hear from owners of other brands of "AR-10" guns, I don't understand the issue. I would think strength and reliability would be a concern for anyone dropping $1500+ for a gun? From what I've read and seen on forums and in conversations with people who own other brands, I'm not impressed with the Ruger, DPMS, Bushmaster, S&W, or anything else in the same price range as the RRA.

I also don't understand the Clinton AWB having anything to do with the design of the gun and the use of FAL mag? No one else made 20rd 308 mags at that time? Was the FAL mag the only 20round mag available? Why is the FAL mag a problem? Millions of them in service, 60yrs of real world torture testing in all environments, and the ability to use metric or inch pattern would seem to be a benefit not a problem.

I'm new to the AR game compared to other firearms, so forgive me if I'm at a loss for your reasoning and statements

One of the conditions of the Clinton AWB was that no new "high capacity" magazines (anything over 10rds) could ever be made again for us lowly peasants' consumption.  As a result, ArmaLite Inc. had to find an existing surplus magazine to build the AR10 receiver around, if they were to offer a 20rd mag.

Rock River had a design as well, but they licensed it to Bushmaster.  Using the same approach, but with FAL mags, the BAR-10 was born.  Within a year, the Clinton AWB expired (it was only a 10-year bill), and there was no need to try to design the AR10 around any other magazines that were made for totally different rifles.

Manufactures could again start making new, peasant-grade 20rd 7.62 mags.

The reason the LAR-8 receiver set is so beastly long, is because of the mag catch assembly to articulate with the rear of the FAL mag block.  This creates an obesely strange BCG and receiver set, that is no longer justified by the Clinton AWB.

Quality is about manufacturing consistently to a standard.  RRA has plenty of challenges in that regard.  I am only talking about designs. If RRA took certain aspects from the LAR-8, and applied them to a new, shortened, lightened, and innovative receiver/BCG set for .308-based cartridges, they would be the first real competition to the DPMS GII.

Very educational post on AR10. Thanks for doing this LRRPF52.

I came across this Kaiser KR7 a couple of months ago online.
It is a .308 DI AR with forward charging handle. Made by Kaiser Works, now out of business





Original Posted from here: Calsgun Forum

This is by far, one of the best posts I've read with regard to the AR-10. Thank you!

Lots of ORIGINAL info here
http://www.ar15.com/archive/topic.html?b=3&f=123&t=525500

Careful digging shows the buffer tube and rear half of the carrier on the Dutch AR10s are larger in diameter than the newer AR10s. The rifles were however lighter than most current AR10s due to a heavily fluted(finned as they called it)barrel.

Grey Ghost Precision just added an AR10 to their line-up.  It's built on Mega billet sets, with top-end components.