The Best Full Auto BB Guns of 2024, Tested and Reviewed

As a kid who grew up with a Daisy in his hands, I couldn’t have fathomed the full auto BB guns we have today. BB guns are one of the most foundational tools for marksmanship and gun safety education for young hunters and shooters. They’re also a hell of a lot of fun. Generations of us grew up honing our skills in backyards and woodlots with lever-action and pump-up BB guns, but we’d be lying if at one time or another we didn’t wish they offered a bit more. It was a thrill to finally field my Crosman semi-auto rotary-magazine pellet rifle when I saved up and bought it, but it doesn’t hold a candle to the BB guns available today.

Full-auto guns inspire a child-like captivation to nearly all shooters — except those who have shot them extensively, and had to pick up all the brass, or the occasional grouch. Shooting machine guns is fun, but it’s something the average person doesn’t often have the opportunity to do. Thanks to the National Firearms Act, Gun Control Act, and later amendments, getting a full-auto firearm, although legal and not terribly difficult, is extremely expensive. You know what’s also a hell of a lot of fun, safe to shoot in more places, and produces no brass to pick up? BB guns. These days, a shooter can pick from the best full auto BB guns and have them shipped right to your door.

Testing and Picking The Best Full Auto BB Guns

There are many full auto BB guns to choose from, and the one that’s best for you should be reliable, accurate enough to meet your expectations, and imitate the design of one of your favorite full-auto firearms — even if you’ve never been able to dump a magazine through the real thing. I’ve been shooting most of these BB guns for several months, blasting away at arrays of tin cans with my kids, but also gathering some meaningful metrics. I burned through thousands of BBs to gather data for accuracy, velocity, to get a sense of reliability, estimate how many shots you can expect to get per CO2 cartridge, and other general strengths and weaknesses of each design. 

For accuracy, I recorded 20-round groups fired in semi-auto from 7 yards since most of these are pistol or submachine gun configuration. I recorded velocities with my Garmin Xero C1 Pro Chronograph. For accuracy and velocity testing, I used Crosman Copperhead BBs in all guns.

For a fun and informative full-auto test, I printed off copies of the little carnival star targets, where a shooter would get a full auto BB gun loaded with a sleeve of maybe 30 BBs. The goal was to shoot out all the red portion of the star to win a prize. I never won. This fun test was to see which of these BB guns would provide the most thorough and precise full-auto fire.

Best Full Auto BB Guns: Reviews & Recommendations

There are a number of full auto BB guns that you can buy, and I couldn’t test them all. Here are the ones I have tested, and as I test more, I will continue updating this story.

Best Overall: Umarex Legends MP

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Key Features

• Replica of German MP-40 9mm SMG (World War II)
• Action: Open-bolt, blowback
• Select-fire, semi- or full-auto
• BB Capacity: 52
• Power Source: 12-gram CO2 cartridge (x2)
• Sights: Non-adjustable rear notch, front post
• Stock/Furniture: Metal under-folding
• Weight: 8 pounds, 3 ounces (measured)
• Trigger: 7 pounds, 9 ounces (measured)
• Average Velocity: 395 feet per second
• Velocity Standard Deviation: 6.3 feet per second
• Group Size: 1.277 inches (20 shots, 7 yards)
• Price: $173

Pros

• Realistic weight 
• Great detail and features
• Detachable magazine holds CO2 and BBs (extras can be purchased)
• Accurate 

Cons

• Doesn’t work as well with copper-plated BBs

Part of the fun of a full auto BB gun is the feel of shooting some of the guns you grew up reading about or seeing in the movies. Umarex’s Legends line is full of hyper-realistic BB guns, but one of the very best is the MP, a copy of the WWII-era German MP-40 submachine gun. This is a full-sized replica that weighs about what a real one would weigh and is constructed in the same manner. The bulk of the gun is metal, and the grip panels and lower receiver cover are plastic — the real ones were Bakelite, a primitive molded plastic. 

The MP has an under-folding stock, just like the real one, and for an adult, I found it quite natural to point and shoot from the shoulder. The sights are pretty accurate, and this gun printed one of the tightest 20-shot groups of the test. It came in second for use on the carnival star shootout, but didn’t lag by much. Its spring-loaded magazine holds 52 BBs and 2 CO2 cartridges at a time. You can expect about 150 shots before the CO2 starts petering out. The spring-loaded magazine works best with slick, silver-colored BBs or more ideally, the black-coated Hornady/Umarex BBs. Sometimes the copper-plated BBs don’t flow through the magazine consistently.

The charging handle locks the bolt back like the real open-bolt design, and the bolt cycles with each shot. That does rob some CO2, but it’s worth it. In reality, it probably doesn’t feel much different than shooting a real MP-40, as many of those 9mm sub guns are quite controllable. Many of the Umarex WWII-era replicas are top-quality BB guns, and the MP is one of the very best.

Read Next: The M1 Carbine: The Most Prolific American Small Arm of World War Two

Best Modern: Crosman ST-1

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Key Features

• Action: Closed-bolt, blowback
• Select-fire, semi- or full-auto
• 300-BB capacity
• Power Source: 12-gram CO2 cartridge (x2)
• Sights: Red dot
• Stock/Furniture: Telescoping stock
• Weight: 6 pounds, 8 ounces (measured)
• Trigger: 11 pounds, 6 ounces (measured)
• Average Velocity: 293 feet per second
• Velocity Standard Deviation: 26.1 feet per second
• Group Size: 3.856 inches (20 shots, 7 yards)
• Price: $183

Pros

• Futuristic design with good ergonomics
• Ambidextrous selector
• Removable three-lug faux suppressor
• Includes red dot sight
• Quick to reload

Cons

• Heavy trigger
• BB hopper door isn’t especially durable

If the vintage-style BB guns don’t excite you, it’s hard to go wrong with the futuristic storm-trooper-blaster-looking ST-1 from Crosman. This full auto BB gun looks to be at least partially inspired by the white Kriss Vector CRB, but there are some design differences, too. The ST-1 is a compact BB gun with a telescoping stock and modular barrel design. In short configuration, the end of the .177 cal barrel is shrouded with a three-lug mount like what you’ll see on an MP-5 or semi-auto SP-5, and the ST-1 has a 13-inch, quick-detach faux suppressor with a barrel that mates up to that of the one on the gun — effectively lengthening it.

The ST-1 has great ergonomics, with a pistol grip and magazine well that have inlaid rubberized texture panels and AR-15-style controls. It has an ambidextrous safety selector and AR-style bolt catch, and the bolt has an external charging handle where the ejection port would be on a real gun. The charging handle is a bit small but not problematic. The ST-1 has a full-length pic rail on the top, and shorter sections of rail on the sides and bottom near the front of the gun for attaching all your cool-guy accessories. One nice accessory that the gun comes with is a holographic red dot sight. It’s a bit dim in bright light, but has a large window and is functional. 

This full auto BB gun has a large removable magazine that, like most others, houses the CO2 and BBs. The ST-1’s magazine holds 2 CO2 cartridges and features a spring-loaded magazine and BB hopper. The hopper holds about 300 BBs, and to charge the magazine, simply draw back a tab on the hopper, shake the 25 BBs into place, and press the rod back into the magazine. The spring-loaded design keeps a steady stream of BBs feeding, and it’s the quickest of the full auto BB guns to reload. The only downside is that the hopper door on mine eventually wouldn’t stay closed, so I had to secure it with a piece of tape. You should be able to expect about 100 shots before needing to change the CO2.

Most Accurate: Umarex Legends Thompson M1A1

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Key Features

• Replica of Thompson M1A1 submachine gun
• Action: Open-bolt, blowback
• Select-fire, semi- or full-auto
• 30-BB capacity
• Power Source: 12-gram CO2 cartridge (x2)
• Sights: Rear peep, blade front
• Stock/Furniture: Wood-like plastic stock, grip, and fore-end
• Weight: 7 pounds, 13 ounces (measured)
• Trigger: 7 pounds, 13 ounces (measured)
• Average Velocity: 411 feet per second
• Velocity Standard Deviation: 5.4 feet per second
• Group Size: 1.138 inches (20 shots, 7 yards)
• Price: $199

Pros

• Good ergonomics
• Great accuracy
• High velocity
• Fast rate of fire
• Extra magazines available
• Authentic operation

Cons

• Wood-finish plastic furniture doesn’t feel durable

There are few well-rounded men who didn’t, at some point, wish they had a Thompson submachine gun. Bang-for-the-buck, the Umarex Legends Thompson M1A1 is hands-down the best way to get a Thompson submachine gun as an adult — or at least get a taste of what it would be like. This full-auto BB gun is another in Umarex’s excellent vintage replica series, and it is the best-shooting one that I tested. This is one that doesn’t closely match the weight of the real model, but a real “Tommy gun” weighs 10 pounds empty, so that’s understandable. Otherwise the M1A1 is pretty damn genuine in its recreation of the original.

This BB gun mimics the open-bolt operation of the real M1A1, and the bolt drops forward and is blown back with each shot, just like the firearm version. It sports realistic controls including a safety lever and semi/full-auto selector. It’s got wood-pattern plastic furniture that is really the only downside of the gun. I never encountered any problems, but the hollow plastic doesn’t provide the genuine feel that some of the other models have. I’m a little paranoid about breaking it.

The metal receiver and magazine are durable, and you can get extra magazines for it — each of which holds the two CO2 cartridges and a loadout of 30 BBs. This full auto BB gun has a screaming fast rate of fire. I appreciate the nod to realism from Umarex by regulating the rate of fire of each of these vintage-design guns to relatively approximate that of the real McCoy. Not only is the rate of fire fast, the M1A1 is really accurate. It printed the tightest 20-shot group of the test, and I was able to easily take a big chunk out of the carnival star at the first whack. 

Most Realistic: Umarex Legends M3 Grease Gun

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Key Features

• Action: Open-bolt, blowback
• Select-fire, semi- or full-auto
• 60-BB capacity
• Power Source: 12-gram CO2 cartridge (x2)
• Sights: Non-adjustable rear peep, front post
• Stock/Furniture: Metal wire, collapsing
• Weight: 8 pounds (measured)
• Trigger: 10 pounds, 8 ounces (measured)
• Average Velocity: 440 feet per second
• Velocity Standard Deviation: 5.1 feet per second
• Group Size: 1.4 inches (20 shots, 7 yards)
• Price: $199

Pros

• Realistic weight and detailed features
• Medium-slow rate of fire similar to real thing
• Consistent velocity
• Extra magazines available
• Safe, semi-, or full-auto selector

Cons

• Some BBs function better than others in the magazine
• Some CO2 cartridges are harder to pierce in this gun

Despite being as ugly and cheaply-manufactured as the genuine M3 submachine gun was, I’m enthralled with it. This reproduction BB submachine gun made by Umarex is almost as cool as the real thing. It’s part of the Legends series of historic firearms that includes the Thompson submachine gun and the German MP-40.

The Umarex M3 Grease Gun is a heavy, well-built BB gun. It weighs 8 pounds and is primarily metal. Unlike many other BB guns, the M3 feels durable. It also displays great attention to detail like imperfect mock welds where the real M3’s stamped parts were welded together. There is a flip-up dust cover and a thumb-cocking recess in the bolt. It has sling mounts where WW2-issue web slings could be attached, and simple, fixed sights. 

The power behind this BB gun is in the magazine, which holds two CO2 cartridges and a loadout of 60 BBs. I found that the Umarex/Hornady BBs and ASG Blaster BBs functioned best. The Crosman Copperhead BBs sometimes didn’t feed through the magazine smoothly. While firing, the bolt actually cycles, then drops forward when the last BB in the magazine has fired — just like the real open-bolt M3. This operation robs some of the CO2, but you can usually get through about 180 BBs before you need to swap cartridges. 

Sticklers will point out that the rate of fire is much faster than a real Grease Gun, but if you can’t overlook that, you’re a Scrooge. I found it to be a good balance of speed and precision. Because of its sub-gun status, I tested the M3 for accuracy at 7 yards, and it held a tight, but slightly off-center group. No matter, one can simply strafe into a row of empty cans and clean house. This is truly an awesome, insanely fun BB gun that will make anyone smile.

Best Value: Umarex Legends Mauser M712

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Key Features

• Action: Closed-bolt, blowback
• Select-fire, semi- or full-auto
• 18-BB capacity
• Power Source: 12-gram CO2 cartridge 
• Sights: Range-graduated rear notch, front post
• Stock/Furniture: wood-pattern plastic grips
• Weight: 3 pounds, 3 ounces (measured)
• Trigger: 3 pounds, 15 ounces (measured)
• Average Velocity: 326 feet per second
• Velocity Standard Deviation: 13.2 feet per second
• Group Size: 2.484 inches (20 shots, 7 yards)
• Price: $120

Pros

• Realistic weight and feel
• Great trigger
• Metal construction
• Blistering rate of fire
• Good price

Cons

• Blowback action robs CO2, only approximately 36 shots per canister

Many of the best full auto BB guns, like the M1A1 Thompson, will cost you around 200 bucks, but the most affordable one in this test is quite a bit less expensive than that. Considering that it’s still a great-quality BB gun, it was an easy pick for best value. Another one of the intricately detailed Legends series, the Umarex Pistol M712 is a replica of the somewhat goofy-looking Mauser broomhandle C96, specifically the M712 Schnellfeuer. 

This BB machine pistol has the heft and feel of the real thing, and runs off a single CO2 cartridge that’s housed in the magazine along with 18 BBs at a time. The broomhandle grip has wood-look plastic grip scales, and the rear of the grip actually has the slot that would have been used for attaching the carrying case stock on the originals. Also like the original, it has cocking tabs to draw back the bolt and cock the long hammer. When firing, the mechanism operates just as the real thing would when cycling. The safety and semi/full-auto selector are true-to-form, and the rear notched sight is graduated and movable — many replicas forego details like that. 

This Mauser M712 replica will blow your hair back the first time you touch it off in full-auto mode. It has a scorching rate of fire, and you’ll be astonished at how quickly it will empty its magazine. The blowback operation is enough to make anyone giddy, and the only downside is that you’ll only get through about 2 magazines before needing to change the CO2 — though shot-per-canister, it’s close to what the other designs get. It’s not particularly accurate, but full auto BB guns are more about fun factor than precision.

Things to Consider When Buying A Full Auto BB Gun

Aside from local ordinances, rules, and pesky things like that — some local laws might prohibit you from shooting BB guns in your backyard — the most important thing to consider when picking from the best full auto BB guns is simply what you want. That’s right. For all the dead-serious gear coverage we do, where one item will serve you dramatically better than the next, this one is more about satisfying your own fun meter than hard performance metrics. That being said, take your budget into account, and how easily you can get things like CO2 cartridges — cause you’ll go through lots of them. I would spend a little extra money to order high-quality coated BBs, as they seem to function the best in all these guns. Have fun and be safe.

FAQs

Final Thoughts On the Best Full Auto BB Guns

It’s not often that I get to test gear that is purely for indulgence in fun, but it’s wonderful when it happens. Full auto BB guns were something I could only dream of as a kid, and they don’t disappoint as an adult. There are lots of them that are reliable, well-made, and accurate enough to zip across rows of cans, sending them to the junkyard in the sky. Sometimes it’s OK to splurge on something that has no practical value aside from putting a smile on your face. You’ll burn through lots of BBs and CO2, but the relative cost compared to shooting as much real ammunition (even rimfire) is low. I’ll caution you though, once you try it out, you might be hooked.