Thumb Operated Receiver: A New AR from Iron Horse Firearms

Sometimes a firearm development is enough to make an even jaded reviewer do a double-take. That was my experience when I saw the details on the new Thumb Operated Receiver from Iron Horse Firearms. [Ed. note: Iron Horse Firearms is now known as Blackwater Worldwide.]

The new Thumb Operated Receiver, or TOR, is an AR-style lower that eliminates the traditional trigger entirely and uses an inline hammer release located at the top, rear of the pistol grip. This inline trigger is most easily operated with the thumb of the hand grasping the pistol grip.

General Features

With any new design like the TOR, not all parts will be 100% compatible with other AR-15 rifles. So, I reached out to Iron Horse Firearms to get additional details.

Iron Horse Firearms TOR

The TOR obviously uses a proprietary fire control system. This includes the safety and pistol grip. However, the rest of the lower, including the buffer tube assembly, is all mil-spec.

Iron Horse Firearms advises that the lowers are compatible with any cartridge that feeds from a mil-spec sized magazine. So, cartridges like the .450 Bushmaster should run without difficulties with a TOR lower.

Benefits of the TOR

According to the company, an inline trigger like the one found on the TOR offers a number of benefits. These include improved accuracy, easier training for new shooters, improved safety, and accessibility to people who have lost fine motor control of the pointing finger normally used for pressing a trigger.


By having the trigger inline with the bore, Iron Horse Firearms suggests that the TOR can reduce pulling left or right that can be an issue with traditional triggers. While it cannot reduce a shooter “pushing” the muzzle down in anticipation of the shot, reducing a side to side pull would be a worthy improvement.

Another factor the Thumb Activated Receiver could improve is the reduction in accuracy related to cold temperatures affecting the shooter’s finger dexterity. If you’ve ever shot in cold temps, you know joints and fingers can stiffen up. Releasing the hammer via a thumb switch may be a way to counteract those effects.

Shooting the Iron Horse TOR

New Shooters

Trigger control is just one of the things a new shooter has to learn when picking up a gun like the AR-15. Take up, break, follow through, reset – these things might be streamlined with a thumb press trigger. Iron Horse Firearms suggests that one of the goals of the TOR is to improve the range experience of the new shooter. I’d have to try one of these guns out for comparison, but I can see how it might work for this.


Iron Horse Firearms designed the thumb trigger to sit in a sheltered area at the back, top of the pistol grip. This area is protected by the receiver on both sides and from above. You can only access the trigger from one direction.

It is fairly easy to see how this design could reduce accidental discharges from things entering the trigger area that were not intended such as a branch when moving through the woods. Yes – your AR safety should be on when moving. Nevertheless, the TOR would appear to offer an additional layer of security.

After all, you never know when your dog will take your gun off safe before pulling the trigger.

Disabled Shooters

For any number of reasons, a person can be completely competent to handle a firearm but not have good control over his or her pointer finger (the finger typically used to pull a traditional trigger.) I’ve met combat vets who have lost fingers on their dominant hand and have had to transition to shooting with their reaction hand.

I’ve also met people who had lost some mobility in their fingers due to arthritis or other conditions. The fact is these folks are perfectly safe shooters, but the traditional trigger systems were no longer ideal for them to use.

An alternative trigger like the one offered by Iron Horse Firearms has the potential of keeping these people in the shooting sports. Also, the TOR would give them the chance of using a rifle for self-defense should they ever be confronted by a violent criminal.

Variations & Availability

Thumb Activated Receiver

Right now, the company is offering only serialized lowers, not complete firearms. However, you can drop any standard AR upper on the Iron Horse TOR and immediately go to the range.

The lowers are made of 7075 aluminum with an anodized black finish. It is unclear at the time of this writing if the metal has been T6 tempered or if the finish is Mil-A-8625 Type III. I suspect they are, but cannot say for certain. As I get more information, I will update this article.

Initially, there are two TOR variants being offered. The first is a stripped lower. This will ship as the serialized lower with the trigger assembly, grip and safety set only. It has a suggested retail price of $249.99.

The complete lower will ship with a buffer set, buttstock set, magazine release, and all of the typical springs and pins. This option has an MSRP of $349.99.

I have inquired with the company about some of the specifics such as if the buffer tube is sized for mil-spec or commercial stocks. When I have additional details, I will update this article.

At the time of this writing – January 2019 – the company is accepting pre-orders on the new receivers with an anticipated shipping date of April 2019. While I am always cautious about ordering a gun before it is released, the deposit is only $50. So, the investment isn’t a bank breaker.

Last update: October 23, 2022

Final Thoughts

I like innovation, and Iron Horse Firearms has a product that may improve the AR market. At the very least, I can see this product being a game-changer for shooters who have lost some finger use. Depending on how well it lives up to its claims of improving accuracy and the shooting experience, it could even reach a wider market adoption.

I certainly look forward to seeing what the company is able to accomplish in the coming years.

If you are in the industry and want to see the Iron Horse Firearms TOR, it will be at the 2019 SHOT Show. Otherwise, you will have to wait until either the NRA Annual Meetings or when it starts shipping (expected in April 2019.) The company is accepting pre-orders with a $50 deposit.

Note: Images provided by Iron Horse Firearms.

Shooting Gear

Store a Glock Magazine in Your AR-15 Grip

AR grip that stores glock magazine

If you are running a pistol caliber AR carbine, or carry a Glock handgun to back up your rifle, TriTech Tactical has a pair of new grips that may interest you. These grips store a Glock magazine in them.

Designed as a replacement for the standard A2-type grip found on most AR pattern rifles, the TriTech Tactical design mimics the interior dimensions of a Glock pistol so that it can carry a spare magazine. Taken at face value, that seems like a good use of space – especially if you are running a pistol caliber carbine that feeds from Glock magazines.

The size and shape of the grips may be off-putting to some. However, since many people seem to like the grip size of a Glock pistol, I imagine that a lot of shooters might like the feel of these in the hand.

TriTech Tactical

One grip, the TPG-ARGL910, is the shorter of the two options. It is designed to hold a subcompact magazine such as those used in the G26 and G27 pistols. The larger of the two products, the TPG-ARGL915, is designed for both the compact and full size Glock models. This should include sizes like the G17, G19, G22 and G23.

Right now, the company is showing these products as being available in mid-January. That is the same time frame as the SHOT Show where the company will be displaying its products. I will try to get by the company’s booth and get a look at these. Be sure to follow my 2017 SHOT Show news page that I will update each day of the event for you guys.

While the full size grip looks disproportionately large on an AR, I’m keeping an open mind on this. These could wind up being more practical than a first glance might suggest. The MSRP is set at $39.95. These are made in the United States.


CMMG MkW Anvil – New AR in .458 SOCOM

CMMG announced a new mid sized AR style rifle that is designed for larger diameter cartridges. Called the MkW Anvil, CMMG custom designed this gun to use the strength offered by AR-10 components, but with an eye to keeping the platform close to the AR-15 compatibility originally envisioned for the .458 SOCOM cartridge.

CMMG MkW Anvil 458 SOCOM Rifle

Expanse M4: Colt’s Cheap AR

With major manufacturers like Ruger and Smith & Wesson driving the price of entry-level AR rifles down, Colt responded in 2016 with a new rifle called the Expanse M4. The new rifle is a (very) basic AR-15 that comes in with a suggested retail price of $699.

Colt CE1000

The new rifle is a direct impingement gun with the basic M4-style features. It has a collapsing buttstock, pistol grip and A2-type front sight assembly. A polymer two-piece handguard is standard.

Colt Expanse M4

As is typical for AR-15 rifles, this gun is chambered in 5.56 NATO. It can safely fire both 5.56 and .223 Rem ammunition.

Colt Expanse CE1000 Review

The 16.1″ barrel has a 1:7″ twist that should allow it to stabilize most of the bullet weights commercially loaded for the calibers.

Colt CE1000 Expanse

Colt uses a flattop upper and does not ship with a rear sight. However, the Picatinny rail makes adding one a quick process. Many people will opt to add a red dot like the Trijicon MRO instead of, or in addition to, a rear sight.

Colt CE1000 Review

A single 30-round aluminum magazine ships with the Expanse M4.

Colt states on its web site that these rifles do not ship with a forward assist or dust cover. That’s unfortunate as these items are pretty standard with even budget AR rifles. (Thanks to reader TechnoTriticale for pointing this out.)

Colt Expanse Specifications

Here are the specs for the Colt Expanse:

Model #CE1000
Caliber5.56 NATO/.223 Rem
Magazine Capacity30
# of Included Magazines1
Barrel Length16.1″
Overall Length32.0″-35.5″
Actionsemi-automatic, direct impingement
Stock6-position, adjustable length

In the wake of the Sandy Hook buying frenzy, there was a glut of AR rifles on the market. In economic terms, supply exceeded demand and prices dropped. 

Colt Expanse Price

While there have been a number of smaller manufacturers that have targeted the budget-priced AR market, additional pressure was applied by the introduction of lower-priced models from more prominent gun makers adjusting to consumer expectations of less expensive rifles.

Colt Expanse M4PSA FDE AR-15Ruger AR-556S&W Sport II
Caliber5.56 NATO5.56 NATO5.56 NATO5.56 NATO
Magazine30 round aluminum30 round Magpul PMAG30 round Magpul PMAG30 round Magpul PMAG
# of Included Magazines1111
Barrel Length16.1″16.0″16.1″16.0″
Twist Rate1:7″1:7″1:8″1:9″
Chrome Platingnonobolt carrier, gas keyfiring pin
Finishunknownhardcoat anodized FDEMilspec Type IIIArmornite
Handguard2-piece2-piece Magpul MOE M-Lokeasy removing 2-piece2-piece
Pistol GripA2-styleMagpul MOERuger gripA2-style
Front SightA2-styleA2-stylemilled A2 Style with QD-socketA2-style
Rear Sightnonefolding Magpul MBUSfolding Rugerfolding Magpul MBUS

On a price-to-features comparison, the PSA AR-15 makes the most sense for a budget rifle. You can see my PSA AR-15 review here.

Smith & Wesson seemed to be doing well with it’s budget friendly M&P15 Sport rifles that were selling for less than $700 in many shops. Then Ruger introduced the AR-556 – another entry level rifle that came very well equipped with an MSRP of $749. Both of these rifles allowed a novice AR shooter to buy a rifle from a readily recognizable name.

Colt Expanse Upper

With the Expanse M4, it seems Colt is trying to capitalize on its name to reach new shooters buying their first AR rifle and more experienced hands who prefer the Colt name as a basic platform to build a more custom gun.

Watch for additional information on the Colt Expanse M4 and other new guns at the special 2016 SHOT Show page I have set up.

Last Update: June 26, 2022


Olympic Arms MPR 308-15 Multi-Purpose Rifle

Olympic Arms MPR 308-15

Olympic Arms introduced a new rifle at the 2015 SHOT Show that is bound to catch people’s attention. The new gun combines the modularity (and calibers) of the AR-15 platform with the ability to also shoot .308 Win and other short action cartridges merely by swapping the upper.

The bonus is the rifle is not crazy expensive either. Let’s take a look at the new MPR 308-15 Multi-Purpose Rifle…