Full-Auto Simulators (2024)

This article originally appeared in RECOIL ISSUE 34
Even Better Than the Real Thing?

Production for civilian-transferable machine guns ended in May 1986. The law of supply and demand drove up prices of transferable machine guns through the roof. When the cost of an entry-level, full-auto-converted AR-15 was equal to a classic muscle car, the market responded by producing full-auto “simulators.” These devices allow shooters to fire rapidly while staying within the confines of federal law.

Such devices have come to the forefront of public attention in light of the Las Vegas shooting that occurred as we wrote this article. While we refuse to fearmonger or steer business to price gouging panic-sellers, the possibility of these items facing additional regulation isn’t unrealistic. Even the NRA came out in support of a regulatory re-look at the devices, possibly in an effort to preempt Congress from taking up the matter.

We’re not going to tell you if a full-auto simulator is right for you, if now’s the time to hurry up and buy, or even comment on the worthiness of such an investment. But because there are numerous options in this niche corner of the aftermarket that may be given an expiration date based on recent events, we do want to educate you on the products that are out there, what benefits they offer, and what trade-offs might be required of the shooters who use them.

There are a number of options for the AR-15 shooter; from bump-fire stocks such as the Slide Fire SSAR-15 MOD and Texas Bump Fire to triggers such as the Fostech Echo, Franklin Armory BFS III, Geissele BGRF, and Digitrigger 1.2. There are even shooting techniques that can get you there.

Prices range from $100 to $800. Are the pricier ones worth it? Do you get what you pay for regarding the inexpensive mods? Are these legal in all 50 states?

After the Hughes Amendment passed, the only thing shooters could do to simulate full-auto fire was bump-fire their rifle. There were a couple of ways to do it. The shooter either held the rifle in a loose manner and let it move back and forth against their trigger finger, or they picked up a “Hellfire” trigger that shortened the trigger’s return. Both required a certain technique, and, as the company producing the Hellfire went out of business, we were left with just the bump-fire method. In many ways, that act alone was superior than installing a trigger gimmick.

Bump Fire and Slide Fire

Two companies manufacture stocks that can be installed on an AR-15 pattern rifle with minimal fuss: Texas Bump Fire and Slide Fire.

Installation is simple and requires replacing your existing rifle’s pistol grip with an Interface Block. This resembles the top ½ inch of your existing grip and retains the selector detent and spring.

We advise measuring before installation; we ended up having to shorten our selector detent spring by two coils in order to get our selector to work with both stocks.

The Slide Fire stock simply slides over your buffer tube and is secured by a locking pin attached to the stock.

Once installed it’s a rather good-looking arrangement and can be used in a locked position where you fire it like a regular rifle, or unlocked where you keep your finger against a rest and let the rifle move back and forth under recoil.

It took us some time (and a lot of ammo) to be able to get the hang of it. We kept trying to work the trigger like we normally do and at one point almost gave up in frustration as our own ability to rapid fire seemed better than trying to bump fire the rifle.

A friend pointed us in the right direction, by demonstrating how the shooter needs to hold his finger straight and rigid against the rest and let the trigger hit it under recoil.

The Texas Bump Fire stock installs in a similar way and works just as well, once you know what you are doing. It’s not as refined looking as the Slide Fire, but it comes in at less than half the price.

Pros:
The price is a major factor here as the Bump Fire can be found for less than $100 and the Slide Fire for about $200.

Cons:
There’s a bit of a learning curve, particularly if you’re an experienced rifle shooter, and results for us were very mixed. There’s also the look and feel aspect that some shooters won’t be able to get past. If you have an extra stripped lower receiver and want to build it into something that lets you waste ammunition and have a little fun that’s the route we suggest, just move an upper onto it and have at it.

Where to get one:
www.slidefire.com
www.bumpfiresystems.com

Legality:
Neither company’s websites states that the product is banned anywhere; however, the State of California has declared it to be a “multi-burst trigger activator” and therefore illegal.

Geissele’s BGRF (Brownells Geissele Rapid Fire)

If the stocks, binary triggers, and digi-trigger aren’t your thing, we recommend the Geissele BGRF.

The BGRF Trigger may not the best choice for bench rest shooting, precision shooting, hunting or three-gun, because it’s a little too fast for most shooters. This is most evident when the 3.5-pound spring is installed. It may sound like a slight difference than the 4.5-pound spring, but trust us, it’s not.

It’s not as fast as full auto, but of all the full-auto simulators we tested, this one will probably keep you the most accurate. It’s advertised as a two-stage trigger, but it really feels like a single-stage, it works well in conjunction with a bump-fire–type stock, but we like it best for well-aimed rapid fire.

Installation is extremely easy and unlike some of the other devices, it’s 50-state legal (although whether or not your rifle is may be another story).

Pros:
Even without true simulated full-auto fire, this is an incredibly fast shooting trigger. We have one in our SBR and can work it pretty fast when we want to just have fun. The price is often a hair under $200.

Cons:
It really lacks the speed of even a Bump Fire stock if you’re looking for simulated full-auto fire, first. Installation is a pain in that the wire EDM cutting used to make this trigger makes for some very sharp edges.

Where to get one:
www.geissele.com

Legality:
The BGRF is legal in every state.

Binary Triggers: Fostech Echo and Franklin Armory

A binary trigger works as its name suggests, by two separate actions of the trigger. The rifle fires normally with the first squeeze and then fires a second shot upon its release and return forward. This action is accomplished by moving the selector to the third position so that the rifle has three modes: safe, semiautomatic, and binary. Both triggers ship with an ambidextrous safety that allows rotation to the third trigger position.

The concept isn’t new. Trap shooters have been using triggers that fire on release for decades, and back in the 1980s there were a few binary triggers floating around the gun show scene. However, Franklin Armory and Fostech have taken these to a new level.

While they provide the same function, each one works a little bit differently.

Franklin Armory’s BFS (Binary Firing System) trigger requires a more detailed installation and, depending upon your lower receiver, it may just drop in or you may have to file metal from the lower or add shims to ensure a proper fit. We had no problems whatsoever in this regard, but have heard of other shooters having this issue.

If you decide to buy one, read the instructions over several times and ensure you understand how the unit is installed. We also advise giving the company CEO’s YouTube installation video a onceover before and during installation and do it on a laptop, PC, or stream it to your flat screen as resolution may not be the best. Franklin Armory advises attaching the included sticker to the lower on which you’re using, or you can have the third position’s marking engraved.

The Fostech Echo dropped in with little fuss — a good thing as it’s a more complex-looking design, even though the Franklin sports three sears. At one time Fostech required the use of a bolt carrier they supplied, which added cost to the build. However, the latest version can be used with an M16 full-auto bolt carrier in order to prevent hammer follow in Binary mode. Fostech’s Echo incorporates a trigger lock for additional safety.

Performance is similar on both triggers, and at first will take a little getting used to. Franklin Armory’s BFS unit runs a bit faster than the Fostech and some shooters have reported stoppages by outrunning the bolt. We suffered no such failures and are running a standard M16 carrier with a standard rifle buffer in an M16-A2 clone, a rifle built from parts we imported from Guatemala back in our Century Arms days. The lower is a DPMS standard lower from the late 1990s; all other parts were from decommissioned Colt M16-A2s that we imported as parts kits.

As far as regular operation, the Franklin Armory BFS has a release of about 4.5 pounds on semi-auto and feels like a cleaned-up military trigger. The Fostech Echo breaks at 4 pounds, but seems like a longer pull than normal.

If you’re a trigger snob, you may not like that aspect, but there may be something else in this realm for a bit more money.

Pros:
Both triggers perform as advertised. This is about as close to three-round burst as you can get without buying a real M16-A2.

Cons:
The price point can be a stickler, and if you like a real crisp trigger in your rifle as opposed to a polished military-grade version, there’s that aspect. All things considered the MSRP on either of these is still much less than a full-auto machine gun: $387 for the Franklin Armory BFS, $479 for the Fostech Echo 2.

Where to get one:
www.franklinarmory.com
www.fostechoutdoors.com

Legality:
Fostech will not ship Echo triggers to:
> North Dakota
> Oregon
> Washington
> New Jersey

Franklin Armory doesn’t sell or ship to civilians in the following states and/or cities:
> California
> Washington, D.C.
> Iowa
> North Dakota
> New Jersey
> New York
> Washington

Digitrigger 1.2

From Digital Trigger Technologies there is the Digitrigger 1.2, a trigger that fires via a microprocessor housed in the grip and powered by a 9-volt Duracell battery. Yes, the brand of battery is important in this case for reasons that we’ll get into later.
On our first trip to the range we didn’t heed the warning about using Duracell batteries. We used another brand that came brand new out of the box.

In semiautomatic mode with the grip turned off, we had a rifle with a mediocre trigger pull and a pistol grip that was on the slightly bulky side.

Activating the Digitrigger gave us an amazing 1-pound pull in the semi position that did allow us to dump a mag pretty quickly. When we flipped to the third position we heard numerous clicks like a dying airsoft gun but no rounds fired.

A quick call to Digital Trigger Technologies confirmed it was the battery not supplying enough current so we switched out for a Duracell.

Pros:
Extremely effective and fast in both modes of operation. Without the Binary function you get a safe 1-pound trigger that’s faster than the BGRF. In Binary mode it fires as fast, but much smoother than the Franklin and Fostech triggers.

Cons:
This is the priciest of everything we reviewed, and you need to remove the battery as it will drain down quickly. Battery power is probably the weakest link in this device, but should the battery completely fail you still can fire the rifle in non-digital mode. Prices range from $699 for the base model on its own to $1,250 built into a complete Ruger rifle.

Where to get one:
www.digitrigger.com

Legality:
Digital Trigger Technologies, LLC doesn’t sell or ship to the following states and/or cities:
> California
> Washington, D.C.
> Iowa
> North Dakota
> New Jersey
> New York
> Washington

Overall
We have had a Slide Fire for quite some time, but don’t use it as much. Some people love them, ours is more of a strong “like.”
Geissele’s BGRF is a fine trigger that we tend to prefer in just a basic rifle setup.

The Franklin Armory BFS makes our M16-A2 clone feel like the old friend we had shoved into our hands 30 years ago as a 17-year-old Marine recruit, although its semi-auto setting is light-years ahead of anything we fired in the military in an A1 or A2.

Fostech’s Echo Trigger has a smoother feel in semi-auto mode, but is probably tied with our love for the Franklin Armory BFS. It works well in our “Business Rifle” and is most likely the rifle we will grab when the zombies come.

The Digitrigger 1.2 works well with the proper battery installed, but removal isn’t the easiest thing in the world. We aren’t concerned about the government sending out EMF blasts to disable these triggers like some tin-foilers might speculate, but see relying on battery power as its weak point. Maybe 1.3 can use better circuitry or an improved power source.

Legalities
All of these devices have clearance at the federal level regarding legality, yet several states consider them machine guns or “machine gun” parts at the state and/or local level, as we noted above.

However these laws and ATF decisions are always changing. When we started this article, the Auto Glove was one of the items we were going to review. A few weeks later it was declared illegal by ATF, and therefore didn’t make the cut.

As we put the final keystrokes on this article, the events of the October 1 massacre in Las Vegas are still unfolding. Some of these devices may face further scrutiny from the government as a feel-good measure to address the concerns of freedom-hating nanny-statists who don’t understand the way of life of the professional shooter.