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.