How airsoft and BB gun magazines work

by Tom Gaylord
Writing as B.B. Pelletier

Today’s report is another guest blog from reader Ian McKee who writes as 45 Bravo. Today he tells us how airsoft and BB magazines work.

If you’d like to write a guest post for this blog, please email me at: [email protected].

Okay — take it away 45Bravo!

Ian McKee
Writing as 45Bravo

How Airsoft and detachable BB gun magazines work

This report covers:

  • It’s a replica thing
  • Low/mid capacity
  • Most of them are very similar
  • Magazine capacities
  • High capacity
  • It’s high capacity clockwork!
  • Summary
  • Coming in the future

It’s a replica thing

A lot of replica air guns have removable magazines to replicate the look and function of the actual firearm they are copied from. 

magazine lineup
From left to right, is a real 5.56/.223 30 round magazine, a 70 round mid-capacity mag, a “20 round” mag that actually holds 150 rounds of airsoft ammo, a 300 round mag, and a 850 round “fatmag”.

Both airsoft and BB guns, use the same magazine design. The only difference being the size of the projectile being used.

As much we would hate to admit it, many of our replica BB guns were first produced as airsoft guns. A LOT more replica airsoft guns are sold, compared to the replica BB gun market, partly because of laws in many countries that have more stringent regulations on BB guns than they do on airsoft. And parents perceive that the plastic airsoft projectile is less dangerous than steel BBs.  

Low/mid capacity

Spring-powered models that have to be manually cocked for every shot, normally have a full sized magazine that holds just 15-30 of the airsoft projectiles in a single column stack, and the magazine sometimes has small metal inserts inside to give the magazine some extra weight. 

low cap mags
Here are two low-capacity airsoft magazines.

Some CO2 BB guns like the Umarex Legends PPK/S, have a small removable stick magazine and keep the CO2 inside the gun, while some designs like the Sig We The People 1911 BB pistol, and the Crosman SBR (short barreled rifle) have a removable full size magazine that holds the CO2 and the BBs together in one removable unit. 

SBR mag
The magazine for Crosman’s short-barreled rifle (SBR).

Most of them are very similar

But no matter how the airguns function, the BB feed mechanism in the magazine is the same, the projectiles are held in a channel, either single stack, or double stacked, and have a spring-driven follower that pushes the projectiles up to the feed lips, ready to be fed into the chamber when needed.

1911 magazines
Do they look similar? The one on the left is from the Sig We The People BB pistol, the other one is from an airsoft 1911 I have used for over 10 years.

1911 magazines detail
This detail shot shows the similarities much better.

Magazine capacities

Airsofters that are into military simulation games (Mil-Sim), like to use a magazine that features a similar capacity as the firearm it replicates. That way the number of their magazine exchanges  plus their load out (the number of magazines they must carry) matches their real world counterparts.

High capacity

Some magazines for automatic electric guns (AEG) use what is called a mid-cap mag, where the channel that holds the projectiles under spring pressure is longer, and may hold 60-100 projectiles. One of the advantages of a mid-cap magazine is since the BBs are under constant spring pressure, they don’t rattle when you run.

midcap and hi-cap mags
There is a spring loaded tab at the top of each magazine to keep the BBs in place until the magazine is loaded into the gun. The mid-cap mag. is on the left.

midcap inside
The BBs are under constant spring pressure while inside the mid-capacity magazine.

The most common type of magazine for the electric guns are high capacity or “high-cap” magazines. They can hold anywhere from 150 to 1000 rounds or more, depending on the size of the reservoir that holds the projectiles before feeding them into the feed channel. 

magazine bottoms
From left to right, is a “20 round” mag that actually holds 150 rounds of airsoft ammo, a 300 round mag, and a 850 round “fatmag”.

It’s high capacity clockwork!   

The high -cap magazines have a hopper that you pour the airsoft BBs into, and normally they have a wheel on the bottom of the magazine that you wind to compress a clockwork style spring that drives the feed mechanism to feed the BBs from the hopper to the gun. 

highcap mag wheel
That toothed wheel (arrow) is wound to compress a spring that pushes the loose BBs up toward the feed lips of the magazine.

As you wind the magazine wheel on the bottom, you hear clicks that are the anti reversing mechanism that keeps the spring from unwinding.  When the magazine is fully wound, a clutch in the winding assembly causes the wheel to “slip” and you hear the clicking sound different. The magazine is fully wound at that point, and you can normally empty the contents of the magazine without winding more. 

Unlike the other magazines that may have the gas stored in them, the high-cap magazines just hold and feed the projectiles. As the gun cycles, it strips off the top projectile, feeding it into the chamber. It doesn’t matter if the gun is electrically operated, or run from compressed air, or CO2 from a remote tank.

mag wheel in magazine
The magazine wheel in the magazine.

high cap mag insides
The insides are all the same, the larger magazine shells just hold more of the projectiles.

As you can see, they all have the same basic components. The highcap magazines hold the projectiles in the open areas and feed them into the feeding channel, and then into the hopup/nozzle area of the gun, as they are fired.

hi-cap mag feeding
Here you see how the hi-cap mag. takes the loose airsoft BBs and organizes them into a feed channel. That spring you wound with the exposed wheel powers this internal mechanism.

The major downside of a high capacity magazine, if you are playing in an airsoft game, is once you start shooting, there is open space in the hopper area of the magazine, and the bbs rattle when you run. So when you run from cover to cover, you sound like you have a half empty container of Tic Tacs in your pocket.   

By these photos, you would think all airsoft guns are based on the AR-15/M4 platform, but you would be wrong. These were just the magazines I had on hand. Magazines of all capacities can be had for any replica, AK47 & AK74, FN-p90, HKMP5, FNFAL, HKG3, MP7, Thompson M1A1, M14 (ALL of these replica machine guns, and others not listed do come with the giggle switch here in America.)

Summary

If you can think it, it has probably been made into an airsoft gun, with magazines and gearboxes adapted to feed it and fire it. 

Airsoft replicas are available from a Mosin Nagant 91/30, to an electrically operated M134 multi barreled minigun!

M134 minigun
Here is a $3,840 M134 airsoft minigun!

Coming in the future

In a future article, we will cover airsoft gearbox types, and other types of airsoft power plants. 

Cheers,

Ian


SigAir ProForce MCX Virtus AEG airsoft gun: Part 6

by Tom Gaylord
Writing as B.B. Pelletier

Virtus AGE right
SigAir ProForce MCX Virtus AEG right side.

Part 1
Part 2
Part 3
Sig Romeo5 XDR red dot sight
Part 4
Part 5

This report covers:

  • The test
  • Sig 0.20-gram BBs
  • Discharge sound
  • TSD Tactical black
  • TSD Tactical white
  • Summary

Today is the final test of the Sig ProForce MCX Virtus airsoft gun. So far we have tested the velocity and accuracy of 0.20-gram and heavier BBs with the 120 mainspring the gun came with. Then we swapped in the 110 mainspring that was also included and tested the gun all over again.

Today we test the accuracy of the gun with the 110 spring and 0.20-gram BBs. Let’s get right to it.

The test

I shot outdoors at 10 meters. The gun was rested on a sandbag. The Romeo5 XDR dot sight is still zeroed from Part 4.

Sig 0.20-gram BBs

I started the test with the 0.20-gram BBs Sig sent with the gun. They don’t have a BB of their own, and I don’t know whose BBs these are. Ten went into 2.151-inches at 10 meters. The group is centered on the bullseye very well, but it is a little high. So I adjusted the dot sight down several clicks before shooting the next BB.

Virtus group Sig BBs
Ten Sig 0.20-gram BBs went into 2.151-inches at 10 meters. The group is high, so the sight setting was lowered.

Discharge sound

Now that I have a sound meter I tested the discharged noise of the gun. I put my phone 4 feet to the left of the muzzle and pointed the microphone at the muzzle. I write that as a note to myself for standardizing future sound testing. A shot registered 89.1 on the meter. The only comparison I can offer is the .22 CB cap I recorded last week. The phone was farther away for that test and not pointed at the muzzle, and the discharge registered 88.2 decibels. No doubt it would have been a lot louder if tested under the same conditions as the Virtus.

sound meter
The Virtus registered 89.1 decibels Number on the lower right) on the sound meter.

TSD Tactical black

Next I fired 10 TSD Tactical black 0.20-gram BBs. They grouped in 2.565-inches at 10 meters. They are lower on the target and centered very well but still a little high. After this group was completed I adjusted the Romeo5 down 3 more clicks.

Ten TSD black 0.20-gram BBs went into 2.151-inches at 10 meters. The group is well-centered but still a little high, so the sight was adjusted lower again.

TSD Tactical group black BBs
Ten black TSD Tactical BBs were more centered on the target but were not as tight as the Sig BBs.

TSD Tactical white

Next up were TSD white tactical BBs. By this time in the test the sun was behind me and I could see each BB flying toward the target. They seemed to fly in an arc that peaked 3 to 5 inches above the bullseye. But when I collected the target I saw that the BBs had struck in the black or just above. One shot was off the target paper on the high side and the group measures 2.004-inches between centers at 10 meters. It’s the smallest group of the test.

TSD Tactical group white BBs
One BB hit 1/2-inch above the target paper, making this a 2.004-inch group of 10 at ten meters.

Summary

Well that is the complete test of the Sig ProForce MCX Virtus airsoft gun. Based on what we have seen the heavier BBs (0.28-gram and 0.30-gram) are the most accurate, but the 0.20-BBs are not bad, either. Maybe if I had adjusted the Hop-Up for each BB we would have seen something even better. The gun handles the 120 spring readily, though I like the 110 spring for the lower strain it puts on the gearbox. The trigger is great and there were no problems with feeding, once I learned how the magazine operated.

This is a serious gamer’s close quarter battle gun. It’s rugged, reliable, accurate and works exactly as it should. The battery has lasted for all testing on just a single charge.

The Romeo5 XDR dot sight was a real treat to use! It adjusts precisely and I like that 50,000-hour battery life for the ONE AAA battery this sight uses! I will be sad to see this one go home.


SigAir ProForce MCX Virtus AEG airsoft gun: Part 5

by Tom Gaylord
Writing as B.B. Pelletier

Virtus AGE right
SigAir ProForce MCX Virtus AEG right side.

Part 1
Part 2
Part 3
Part 4

This report covers:

  • 110 mainspring
  • BUT
  • Prediction
  • Changing the mainspring
  • Assembly
  • Performance
  • 0.20-gram BBs
  • Rock and roll
  • 0.25-gram BBs
  • Battery
  • Summary

Today we’re going to have a little fun. I know some of you would like to work on spring-piston airguns but you just don’t want to jump into the deep end of the pool — as in buying expensive tools like a mainspring compressor and parts that may or may not work as you expect. Today we are going to change the mainspring in the SigAir ProForce MCX Virtus AEG airsoft gun, and we will do it with two Allen wrenches — nothing more! This is a job any of you can do. Then we’ll test the velocity of the gun and see what impact the new spring has made.

110 mainspring

You may recall that Sig bundles a 110 spring with the Virtus, while the 120 spring comes installed in the gun. First off — what do the numbers 110 and 120 mean? That rating relates to how fast that spring will propel a 0.20-gram BB in meters per second. So a 120 spring should propel a 0.20-gram BB at 120 meters per second, which is 394 f.p.s. That’s regardless of what airsoft gun it’s in.  A 110 spring should propel the same BB at 110 meters per second, which is 361 f.p.s.

BUT

Airsoft springs are also rated with an M or an S (which can also be an SP). The M spring is the one that’s rated to toss a 0.20-gram BB as described above. The S or SP spring is rated for a 0.25-gram BB. The velocity in meters per second remains the same, but since the 0.25-gram BB is heavier, the gun will naturally be even faster with a lighter BB. So the higher the number the stronger the spring and M versus S or SP also figures in.

The 110 replacement spring that comes with the Virtus is an M110 spring, and Sig recommends using 0.20-gram BBs in the gun. They don’t say anywhere that I can see whether the 120 spring that comes installed is an M or an S, but given the ammo recommendation, I believe it is also an M120 spring.

So, what sort of velocity did we see from the 0.20-gram BBs with the 120 spring installed? Sig said to expect a 370 f.p.s. velocity, but we saw an average 410 f.p.s. speed. What I just explained was what the manufacturers say to expect from a 120 spring — 394 f.p.s. That’s real close to 410 f.p.s., so again, I think the gun had an M spring. An S120 spring would have given 394 f.p.s. with 0.25-gram BBs and probably 430 f.p.s with 0.20-gram BBs. Of course, that’s just my guess.

Prediction

So, the Virtus that I’m testing shot on the fast side with its M120 spring — assuming I am correct about it being an M-rated spring. Therefore, I predict that it will also shoot on the fast side with the M110 spring. Instead of 361 f.p.s. I predict a 0.20-gram BB will average 380 f.p.s. I am writing this before shooting the first shot with the new spring.

Changing the mainspring

Changing the mainspring is very easy. First, extend the wire buttstock all the way and then remove the 3mm Allen screw on the right side, where the stock meets the receiver, and the entire stock slips up and off the receiver. By the way, the Virtus manual says the screw is 8mm, but it’s actually 3mm — no doubt a mistake in transcription. When the screw is out, a plastic keeper that it passes through also comes out and the stock slips up and off the rear of the receiver. When reinstalling the stock make sure the V-notches on both sides of the receiver line up with the two heavy wires in the stock.

Virtus AEG stock off
With the screw and keeper out of the stock the entire  assembly slips up and off the receiver.

Once the buttstock assembly is off the gun, the rear of the spring guide is exposed. The manual calls it a screw that you turn 180 degrees, but it’s actually a bayonet keeper. Turning 180 degrees aligns the flanges of the keeper with their raceways and the mainspring pushes the keeper out. Remember that the keeper is under spring pressure, so pressing in on the wrench helps loosen it for turning.

Virtus AEG receiver
With the stock off the rear of the spring guide (arrow) is exposed. Insert a 5mm Allen wrench and turn the guide counter-clockwise 180 degrees.

Virtus AEG  spring out
When the bayonet lugs align, the spring guide is free to come out. This is how far the 120 spring pushes the guide out. You can restrain it easily with your hand.

The two springs compare in this way. The 120 spring is made from heavier wire and the 110 spring is longer — though that may change after a few weeks in the gun. Both springs are wound with what the airsoft industry calls irregular pitch, which means some coils are closer than others. That allows the spring to start compressing easier and then increase in tension the more it’s compressed. It’s supposed to be easier on gearboxes, though you will find a lot of arguments on both side of that issue!

Virtus springs
The softer M110 spring is on top and the 120 is below. It’s not easy to see, but the 120 spring is made from heavier wire. Both springs are wound with an irregular pitch.

Assembly

The Virtus goes back together the reverse of the way it came apart. And it’s just as easy as it sounds. It’s taken me a long time to describe a process that took me 20 minutes to perform — again with just two Allen wrenches.

Performance

Now, let’s find out what installing this lighter spring has done for us.

0.20-gram BBs

First to be tested were 0.20-gram BBs. I believe I am out of the BBs Sig sent with the gun so I used 0.20-gram TSD competition BBs. The average velocity for 10 was 380 f.p.s. Sometimes old BB gets it right on the nose!

The spread went from a low of 370 to a high of 383 f.p.s., so a 13 f.p.s. difference. With the 120 spring the average was 410 f.p.s. with a 6 f.p.s. spread.

Rock and roll

I emptied the magazine on full auto and truthfully could not tell any difference in the cyclic rate this time versus with the 120 spring. There may be some but it’s pretty small.

0.25-gram BBs

Next I tried the same Open Blaster 0.25-gram BBs that I shot before with the heavier spring installed. The average this time was 343 f.p.s. with a 5 f.p.s. spread from 340 to 345 f.p.s. With the 120 spring the average was 365 f.p.s. with a 2 f.p.s. velocity spread. At the end I dumped the magazine on full-auto again, remembering to fire a couple shots on semi-auto afterwards to relax the spring.

I did not load heavier BBs for testing. I think the 0.25-gram BBs are as heavy as I would go with this spring, given the velocity we have seen.

So, the 110 spring varies in velocity slightly more than the 120. Of course this spring is brand new and may settle down a bit after a few thousand rounds have been fired.

Battery

I would like to point out that the battery has never been recharged since I started the test and it is still going strong. Not only has it fired many hundreds of rounds including lots of blank shots, it has also been stored charged for two months.

Summary

Next we test the gun for accuracy. If the accuracy is reasonably equivalent to the 120 spring I think I will leave the 110 spring installed. It is no doubt a little easier on the gearbox.

This Virtus AEG is a serious airsoft gun, as I have maintained all along. This is the kind of equipment a skirmisher wants to have for close-quarters battle!


SigAir ProForce MCX Virtus AEG airsoft gun: Part 4

by Tom Gaylord
Writing as B.B. Pelletier

Virtus AGE right
SigAir ProForce MCX Virtus AEG right side.

Part 1
Part 2
Part 3

This report covers:

  • A discovery!
  • The test
  • ASG 0.25-gram Open Blasters
  • TSD Bio 180 0.26-gram BBs
  • TSD 0.28-gram Tactical BBs
  • ASG 0.30gram Blaster Devil BBs
  • Full-auto
  • Summary

Today I’m shooting the Sig ProForce MCX Virtus AEG  with heavier BBs than Sig recommends. You will be able to compare today’s groups with those from Part 3 to see which BB you think is best.

A discovery!

Before we begin I need to tell you about a discovery I made. In the last report the 0.20-gram BBs that Sig supplied with the gun were not feeding well from the magazine, nor were 0.25-gram Stealth BBs. In today’s first test I had the identical problem and discovered that it isn’t the BB; it’s the magazine. It does not like feeding the last four BBs when it’s in the semiautomatic mode. So, for all of today’s test I filled the mag with way more than the 10 shots I needed and after the target was finished I went full-auto outdoors in a safe direction with the BBs that remained. All four of the BBs I tested today fed perfectly that way.

The test

I shot all the targets from a rest at 10 meters. Until the last target, all shooting was one round at a time, which is the semiautomatic rate of fire. I did not adjust the Romeo5 XDR dot sight or the Hop Up at all today. I think you will see that things worked out well

ASG 0.25-gram Open Blasters

The first BB tested was the ASG Open Blaster that weighs 0.25-grams. Ten went into a group that measures 2.041-inches between centers.The group is very well-centered and I am happy with it.

Virtus 25 0.25-gram Blaster
Ten ASG 0.25-gram Open Blasters went into 2.041-inches at 10 meters.

TSD Bio 180 0.26-gram BBs

Next to be tested was the 0.26-gram TSD 180 Bio BB. Ten of them went into 4.34-inches at 10 meters. It’s a strange group because 6 of them are in 1.041-inches in nearly the center of the bull. But those four other shots are there and represent some inconsistency. So this isn’t a good group overall.

Virtus 0.26-gram TSD Bio 180
Ten TSD Bio 180 0.26-gram BBs went into 4.34-inches at 10 meters. Seven of them are in 1.041-inches.

TSD 0.28-gram Tactical BBs

Next up were 10 TSD Tactical 0.28-gram BBs. These surprised me when 10 went into 1.804-inches, with 8 in 1.512-inches. This looks like a very stable BB for the Virtus.

Virtus 0.28-gram TSD tactical
The 0.28-gram TSD Tactical BB looks good. Ten are in 1.804-inches with 8 in 1.152-inches.

ASG 0.30gram Blaster Devil BBs

The final BB I tested was the 0.30-gram Blaster Devil. Ten went into 1.661-inches. That’s the best group of ten for this test, but for some reason it didn’t seem like it at the time. When I went outside the dump the BBs remaining in the magazine full-auto, I could see them dropping fast after 10 meters. That is why I didn’t select them for the next test, which will be burst-fire in full-auto.

Virtus 0.30-graom ASG Blaster Devil
Ten 0.30-gram ASG Blaster Devils went into 1.661-inches at 10 meters. It’s the smallest 10-shot group of this test, but I didn’t like how they fell off after about 10 meters when fired longer distances full-auto. 

Full-auto

Like last time, I took what I thought was the best BB overall in this test, which was the 0.28-gram TSD Tactical and I fired a bunch of them at the last target full auto. “A bunch” turns out to be 17 BBs. I shot the Virtus off the rest and held the trigger back until no more BBs came out. As with all the BBs in this test and the previous one, the magazine empties completely in full-auto. You must remember to then place the selector in semi-auto and fire a couple blank shots to relax the mainspring again.

Seventeen BBs went into 3.496-inches at 10 meters when fired full-auto. Notice that they stayed mostly well-centered within the bullseye, with only two BBs straying outside. This would be a good close-range BB for skirmishing.

Virtus full-auto
On full-auto the Virtus put 17 0.28-gram BBs into 3.496-inches at 10 meters.

The Virtus was more accurate today with the heavier BBs than it was in Part 3 with the 0.20-gram BBs that Sig Recommends using. That doesn’t necessarily mean you should use the heavier ones, because distance is also a factor. But it is worth knowing that as the BB weight increases the groups get smaller.

Would the groups have continued to shrink if I had tested even heavier BBs than those I tested today? Perhaps, but after seeing how the heavier BBs dropped in flight after about 10 meters (on full-auto) I thought the gun had come to the upper edge of its BB-handing ability.

It’s now clear to me that the Virtus is designed for short bursts of full-auto fire. It does work in the semi-auto mode and it works quite well, but that’s not what it is designed for.

Summary

We have reached the end of our tests of the Sig Virtus AEG airsoft gun with the 120 spring installed. Next time I will replace this mainspring with the lighter 110 spring and conduct both velocity and accuracy tests again.


SigAir ProForce MCX Virtus AEG airsoft gun: Part 3

by Tom Gaylord
Writing as B.B. Pelletier

Virtus AGE right
SigAir ProForce MCX Virtus AEG right side.

Part 1
Part 2

This report covers:

  • Accuracy
  • HOWEVER
  • Romeo5 XDR red dot sight
  • Sig BBs|
  • 0.20-gram TSD Tactical White BBs
  • 0.20-gram TSD Tactical Black BBs|
  • 0.20-gram Marui Black BBs
  • 0.25-gram Stealth BBs
  • Rock and Roll
  • Discussion
  • Summary

I said in Part 2 that there was a lot to test with this SigAir ProForce MCX Virtus AEG airsoft guns, and today I discovered I was understating the case. You’ll see why as we progress.

Accuracy

This is the beginning of the accuracy test and it’s good to remind ourselves what this airsoft gun is meant for. It’s meant for skirmishing, which means shooting people, not targets. However, the best way to get it on target and properly adjusted is still the old-fashioned way of shooting at paper.

HOWEVER

The However today is all the variables. I will be shooting many different BBs, adjusting the Hop Up and adjusting the Romeo5 dot sight — each of which makes the equation more complex. I did not think about that until I was well into the test.

My plan had been to try several 0.20-gram BBs, and then some heavier ones, since we learned in Part 2 that the Virtus can handle BBs up to 0.30-grams. But I didn’t take into account adjusting the gun and the sight for each BB. Were I to try to do that I could write about just this one airgun for the next month and still not finish. Perhaps you don’t care about the outcome but there are readers who want to know, so I owe it to them to do a thorough job.

Romeo5 XDR red dot sight

I mounted the Sig Romeo5 XDR red dot sight on the Virtus for the test. I must observe that both this sight and the Virtus airgun are precision-made and the installation of the sight took some time. All parts have to mesh, and when they do that sight is on tight!

I adjusted the intensity of the dot as low as it would go and still be visible. That gives the most precision. 

Sig BBs

I mentioned in the earlier parts of this report that Sig sent some 0.20-gram BBs with the gun, so I started the test with them. I first fired a single shot from 12 feet, and when the BB hit the target at 6 o’clock I backed up to 10 meters for the test. 

The Sig BBs were not feeding reliably. After loading the magazine each time it took several shots before they began to feed, so I loaded 16 BBs into the mag for the first target. That’s 4 pumps of the speedloader button. 

The first target has 8 shots on it. There were more BBs left in the gun but they wouldn’t fire out. The 8 BBs are in 2.415-inches at 10 meters. They are high on the target, and in line with the center.

Sig Virtus Sig BB 1
On the first target 8 Sig BBs went into 2.415-inches at 10 meters. 

I adjusted the Romeo5 dot sight five clicks down after seeing this first target. I also adjusted the Hop Up five clicks up. I didn’t know if that was the right way to go, but the next target would probably tell me. There were 4 BBs remaining in the Virtus that were not fired. I loaded another 16 Sig BBs into the magazine.

The second target has 9 shots in the target in 2.341-inches between centers. Once again I had to shoot several BBs to get the gun to fire then and the last 4 BBs would not fire from the gun. They fell out when the magazine was removed.

Sig Virtus Sig BB 2
The second target shot with Sig BBs has 9 shots in it. The group measures 2.341-inches between centers.

By adjusting both the Hop Up and the sight setting I confused myself as to what was happening. But that did not deter me from making the same mistake again. This time I adjusted the Romeo5 dot sight down 6 more clicks and the Hop Up up 6 more clicks. Hopefully something would change. I loaded 20 more BBs into the magazine.

The third target shows 9 BBs in 2.095-inches at 10 meters. The group is a little smaller than the others, so I’m thinking the Hop Up is where it needs to be for now. It also dawned on me that I could be here forever if I tried to adjust both the Hop Up and the sight for each BB. So I decided to leave both things as they were for now.

Sig Virtus Sig BB 3
This third target with Sig BBs shows 9 in 2.095-inches at 10 meters.

Once again there were four BBs remaining inside the gun after the gun stopped shooting BBs out. They were outside the magazine but loose in the gun’s receiver. I had intended for each of these three targets to be 10-shot groups, but this BB feeding problem prevented that.

Sig Virtus BBs
After every round of shots there were always 4 Sig BBs left in the gun.

0.20-gram TSD Tactical White BBs

Next I tried shooting 0.20-gram TSD Tactical White BBs. They aren’t called that on the bag they come in, but on the next target I will shoot 0.20-gram TSD Tactical Black BBs, and the color of the BB is the only difference between the two. The wording on both packages is identical. I loaded 20 of them into the magazine.

This time I got 10 shots in a row! Feeding was perfect. Hurrah! These ten went into 1.747-inches at 10 meters, making them considerably more accurate than the Sig BBs. They hit in almost the same place on the target as the Sig BBs. To keep things simple I did not touch either the Hop Up or the dot sight for the remainder of the test.

Sig Virtus TSD White BBs
Now this is a nicer group. Ten TSD 0.20-gram white BBs in 1.747-inches at 10 meters.

To dump the remainder of the BBs (I had loaded 20 BBs because of the previous experience) I fired them into the backstop on Rock and Roll, once the target was taken down. All BBs were expended from the magazine this time!

0.20-gram TSD Tactical Black BBs

Now I loaded some 0.20-gram TSD Tactical Black BBs into the mag. The Hop Up and sight settings remained the same. Ten BBs went into 2.106-inches at 10 meters. Once again, all BBs fed as they should and I dumped the rest Rock and Roll into the backstop after securing the target.

Sig Virtus TSD Black BBs
Ten 0.20-gram TSD Tactical Black BBs went into this 2.106-inch group at 10 meters.

Once again, all BBs fired from the gun without fail. But the White TSD BBs still grouped tighter.

0.20-gram Marui Black BBs

Next up were ten 0.20-gram Marui Black BBs. They made a 2.377-inch group in almost the same place as the other BBs. They also fed perfectly.

Sig Virtus Marui Black BBs
Ten Marui Black BBs made a 2.377-inch group at 10 meters.

0.25-gram Stealth BBs

I had only planned to shoot 0.20-gram BBs today, since there were so many to test. But I had loaded the magazine with 0.25-gram Stealth BBs before realizing what they were. Since they were already loaded, I shot a final target with 10 of them. As expected they landed a little lower on the target than the 0.20-gram BBs. Ten of them landed in a group that measures 2.175-inches between centers. That’s about as good as the worst of the 0.20-gram BBs. I could play with the Hop Up to try to improve the group, but for today I will leave things where they are.

I want to add that this was the only other BB besides the Sig BB that had feeding problems. Several times during the shooting BBs failed to come out of the gun.

0.25-gram Stealth BBs
Ten 0.25-gram Stealth BBs made a 2.175-inch group at 10 meters.

Rock and Roll

As a final test I took the best BB of the test, which was the TSD White BB — and shot 16 into the target on full auto from 10 meters. I fired two bursts, with the last one being the longest. The gun was rested for this target just like it was for all the others and all the BBs fired as they should.

This group is perhaps the most enlightening one of the day, because it represents what the Virtus can do when it’s used in the way it was designed. 16 BBs went into 2.743-inches at 10 meters.

Rock N Roll
Shooting 16 shots full-auto gives a group that measures 2.743-inches between centers.

Discussion

This Virtus is a serious select-fire AEG. I consider the accuracy we have seen so far to be very respectable. And the gun hasn’t been fully tuned or tested. 

Up next will be the heavier BBs that range from just above 0.20-grams up to 0.30-grams. If I find any more 0.20-gram BBs I will also test them as well.

Following that test, I will exchange the 120 mainspring for the lighter 110 spring and completely test the gun again — both for velocity and accuracy.

Summary

Sig’s AEG Virtus is a serious airsoft airgun. They should be proud to carry it in their ProForce line.


SigAir ProForce MCX Virtus AEG airsoft gun: Part 2

by Tom Gaylord
Writing as B.B. Pelletier

Virtus AGE right
SigAir ProForce MCX Virtus AEG right side.

Part 1

This report covers:

  • My strategy
  • Sig BBs
  • Weight
  • Getting the gun ready to fire
  • Loading the magazine
  • Use the speedloader
  • The follower needs more BBs
  • Velocity 0.20-gram Sig BBs
  • Sound and feel of the shot
  • Rock and Roll
  • More about the speedloader
  • 0.25-gram BBs
  • Full auto accuracy
  • 0.30-gram BBs
  • Trigger pull
  • Summary

Today I start reporting on the velocity of the new SigAir ProForce MCX Virtus AEG airsoft gun. I say “start” because I can’t get the full report in a single day. You will recall that Sig enclosed a 110 mainspring for me to try, as well as the 120 that’s in the gun as it comes. The 110 spring is lighter, so two things should happen. The velocity should drop a little and the rounds per minute (RPM) should increase, because the electric motor is turning the gears against less force.

My strategy

I could either replace the spring and do the second velocity test next or I could go on to the accuracy test with this spring and then do the spring swap and test everything again. I think I will do the latter for a couple reasons. It’s easier, and I am into easier. And, even if I were to do anything wrong while making the spring swap, we will at least get one complete test.

My hope today is to get the velocity for some reasonable weight BBs, and also to sample the RPM. Let’s go!

Sig BBs

Sig provided me with a sample bag of 0.20-gram BBs with the gun. I have plenty of BBs in that weight, but I thought I would use theirs, since they were handy. They even loaded the speedloader — which made it more  convenient. 

Weight

I don’t know what brand BB Sig sent me. They don’t currently have an airsoft BB of their own, so I assume that these are a premium BB. But I weighed them to make certain. They weighed 0.20 grams on the nose except for one that weighed 0.19 grams. I am satisfied that these are premium BBs.

Getting the gun ready to fire

The Virtus AEG is a spring-piston airgun. It just uses an electric motor to rapidly cock and release the piston to simulate full-auto fire. That motor needs electricity to run, so the battery has to be installed in the forearm before the gun will fire. This step used to be extremely hard with the AR-15 airsoft guns I have owned, because the battery has to go inside the forearm that, on an AR-15, is not easy to remove or replace. But on the Virtus it is a snap!

 Virtus and battery
That battery has to go inside the forearm.

Knock out just one pin and the forearm slides off the receiver, exposing the connection plug for the battery. Remember, only the yellow plug on the battery’s longer cable is attached to the gun. The shorter battery cable is for charging, and doesn’t plug into anything while the battery is in the gun.

Virtus forearm off
The yellowish cable connector on the longer cable of the battery connects to the gun’s white plug. The shorter battery cable with the white plug is for connecting to the charger.

I must comment on how much room there is for the battery. On the AR-15s I have owned it was a real task to get the battery to fit inside the forearm and then get the forearm back on the gun. And on one gun the battery went into the A2 butt, which was a real nightmare. I hated it, which is the big reason I got rid of those AEGs. The Virtus is a walk in the park by comparison. I could easily fit two of these batteries in the forearm — one above and the other below the barrel.

Virtus forearm on
The forearm is back on the gun and pinned in place. The battery will fit either above the barrel like it is here, or below. There is plenty of room inside this forearm.

Now that the gun is ready to fire, it’s time to load it.

Loading the magazine

The Virtus comes with an AR-15 lookalike sheetmetal magazine, and from my past experience these mags hold several hundred BBs loosely in the bottom. They get scooped up to feed through the gun and sometimes you get misfeeds. Nobody complains, though, because AEG airsoft guns are fired full auto most of the time. However, B.B. Pelletier doesn’t do things like others do.

I wanted to load exactly 10 BBs into the mag. and shoot them through the chronograph for velocity, then change BBs to a different weight. And that was how I became familiarized with the Virtus mag.

The 120-round Virtus mag has a spring-loaded follower that pushes the BBs up and into the path of the bolt. There is no chamber full of loose BBs. To load this mag you have to hold a spring-loaded catch back for each BB while the follower tries to push the BBs that are already in the mag back out. After fiddling with it for a few minutes I had to change my loading strategy!

Use the speedloader

The speedloader is more than a convenience with the Virtus. It’s a necessary part of loading the mag. I have more to say about it, but for now that’s it.

Virtus speedloader
Stick the nozzle of the speedloader into the nozzle of the magazine and start pressing the loading button on the speedloader.

The first BB I tested was the one Sig sent with the gun. We already know that they are very consistent.

I loaded four 0.20-gram BBs (the speedloader pushes in 4 BBs each time the thumb button is pushed down) into the magazine and then attempted to see what the velocity was. I then fired the gun on semiauto and nothing came out! Oh, oh!

The follower needs more BBs

What I discovered was the Virtus is fresh off the assembly line and needed a little breaking in. I put the selector on Rock and Roll (full auto) and let the bolt cycle many times. It was fun just listening!

I then loaded about 20 BBs into the mag to fire. Once that many were in it fired perfectly every time. And later — after perhaps 50 more shots, it fired all the BBs, even when loaded with just a few. Now that she is running, let’s see what she does.

Velocity 0.20-gram Sig BBs

First up were the 0.20-gram BBs supplied by Sig. On the box the gun comes in Sig says to expect to get 370 f.p.s. from the Virtus, so I was surprised to see that average of the first string reach 410 f.p.s. The low was 407 f.p.s. and the high was 413 f.p.s., so a spread of 6 f.p.s. That’s pretty tight.

Sound and feel of the shot

I was shooting semiautomatically, so each pull of the trigger produced a single shot. There was almost no motor noise, though I could hear the pop of air from the piston. I could feel some gearbox vibration through the pistol grip, but the only real sound was the pop of compressed gas from the piston. I have shot many AEGs and this Virtus has the quietest gearbox and motor I have heard. It’s even quieter than an AR-15 whose gearbox I rebuilt with upgraded steel bearings and gears. That one still had an air-wrench sound to it.

Rock and Roll

Since I overloaded the magazine for the first test, I went outside and dumped the remainder of the BBs on full auto. That told me there is no way I will be able to give you an accurate RPM count. This Virtus sounds like the infamous German MG42 “devil’s zipper” machinegun that had a high cyclic rate. I can count AR-15 cyclic rate up to around 800 RPM. This gun is faster than that. I have read reports of 900 RPM. It’s every bit of that!

More about the speedloader

Now that I was comfortable loading the magazine with the speedloader I found it quite easy to empty the contents of the speedloader to change the BB weight for testing. Just load the mag, then open the speedloader hopper pour out all the BBs except one. Since all the BBs were white and looked identical, this was the best way to keep track of them for the test. That last BB would remain in the nose of the speedloader until I pressed it out after the next BBs were inside. You do have that kind of control over the thumb button. Then that lone BB was returned to its proper container and everything was ready for the next test.

0.25-gram BBs

Given the higher velocity of the 0.20-gram BBs, I tried 0.25-gram Open Blasters from ASG next. They averaged 365 f.p.s. with a 2 f.p.s. spread from 364 to 366 f.p.s. These are going almost as fast as the gun is rated  to shoot with 0.20-gram BBs, and it will be interesting to see how accurate they are.

Full auto accuracy

Since AEGs don’t recoil I indulged myself and went full auto during this velocity test. All the BBs stayed together in a tight group, though my target was only a few feet away. I need to find a way to test full auto in the accuracy test, too!

0.30-gram BBs

I then tried some 0.30-gram Blaster Devil BBs from ASG. They averaged 333 f.p.s. with a 1 f.p.s. spread from 333 to 334 f.p.s. This average is getting pretty slow, so I stopped testing here. Obviously a heavier BB will shoot even slower, but I think we have bounded the useful range of velocity in today’s test.

Trigger pull

An AEG operates with an electric motor, so pulling the trigger doesn’t release a sear like you might think. I will call this a single stage trigger, though the pull effort does increase after a lighter initial pull. The trigger “breaks” at 2 lbs. 2 oz. on the test gun and there is no hesitation of the trigger blade to alert you to the fact the gun is about to fire.

In the manual you are advised to shoot full auto in bursts to preserve the gearbox. You are told not to empty a 120-shot magazine on a single trigger pull. You are also instructed to return the gun to semiautomatic and fire it once blank after a run of full auto. That releases the mainspring in the gearbox. That is common for all full-auto AEGs.

Summary

This Virtus is stacking up very well at this point. It is outperforming another AEG that I custom tuned several years ago, so I am impressed. I hope it turns out to be accurate, though with a full-auto gun we aren’t looking for pinpoint accuracy. That’s not the way these guns are used.

Don’t forget there will be a second velocity test and a second accuracy test with the lighter mainspring after this test is concluded. So, there is a lot more to come.


SigAir ProForce MCX Virtus AEG airsoft gun: Part 1

by Tom Gaylord
Writing as B.B. Pelletier

Virtus AGE right
SigAir ProForce MCX Virtus AEG right side.

This report covers:

  • Spring piston
  • Battery basics
  • Avalon gearbox
  • Replacement M110 spring
  • This gun
  • Sights
  • Magazine
  • Velocity
  • Hop Up?
  • At what price?
  • Discussion
  • Summary

I did a search in the blog archives and could not find another report I had written about automatic electric airsoft guns (AEG). I have done some large articles about AEG in the past for Shotgun News and for my own newsletter. I even wrote two articles for Pyramyd Air about the basics of batteries for airsoft guns — one in 2008 and the other in 2009. Those articles are still good today — 10 and 11 years later.

Spring piston

An AEG is a spring-piston gun whose piston is retracted (cocked) and loosed by a mechanical gearbox that’s powered by a small high-torque electric motor. To power the motor a battery is contained somewhere inside the gun. There is a great animation of how an AEG works on Wiki.

Battery basics

Two things to know about AEG batteries — their milliampere-hour (mAh) rating and their voltage. The higher the milliamp-hours, the longer the battery lasts, which equates to the number of shots the gun gives on a charge. The higher the voltage, the faster the electric motor spins, which equates to rounds per second, because the principal reason for the existence of an AEG is to give full-auto capability.

The gun I am testing has a stick-type lithium polymer (lipo) battery that’s rated at 1100 mAh, which is on the low end, and 11.1Volts, which is quite high. That means a fast-firing gun that will need a recharge sooner than one that has a battery with a higher mAh rating.

Virtus AEG battery
The Virtus stick battery goes in the forearm. The yellow connector connects to the gun’s motor. The white connector is for the charger. The battery must be installed and removed again for every charge.

Stick-type batteries are designed to fit inside tight spaces within forearms. Sometimes there is enough room to stuff in an aftermarket battery with a higher mAh rating for longer operation. Sig says this 11.1V battery is the maximum allowable, but that refers to the volts, only. They don’t address the mAh. I will look into that for you. The thing you don’t want to do is use a battery with a significantly higher voltage, because the gearbox may not take the additional strain of faster operation. The thing is — this battery is already running close to the top in voltage, so you aren’t likely to do that. And then there is the gearbox.

Avalon gearbox

The MCX Virtus AEG has an Avalon gearbox with upgraded steel bearings. The gears are metal as well. I have built up airsoft gearboxes this way in the past, exchanging metal gears for plastic or Nylon, but this one comes to you ready to go.

Replacement M110 spring

The gun comes with an M120 mainspring installed and a replacement M110 spring to swap in if you like. The M110 spring will give a lower velocity (30 to 60 f.p.s. slower for a given weight BB) but put less strain on the motor and less drain on the battery. If you are doing a drill inside close quarters, the 110 spring is the one to have. It will give you longer operating time. If you are outside the M120 is the way to go. Sig has made swapping this spring very easy, and I will test the gun with both springs. I believe at this point that the M110 spring will allow the motor to run cooler longer in the full auto mode. We will see as we go.

This gun

All right, I’m going to stop the tech discussion right there. There is a lot more to tell you, but now I want to shift your attention to the gun I am testing. The MCX Virtus AEG is a close replica of Sig’s MCX Virtus SBR firearm — their short-barreled rifle version of the Virtus. The airsoft gun’s receiver is CNC-machined metal and has M-LOK-compatible slots for accessories in the metal handguard. The metal stock telescopes to three positions and locks solidly in all three. It removes quickly to change the mainspring for power changes.

The gun weighs 6 lbs. 9 oz with a battery and an empty magazine. The length runs from 25-3/4- to 29-inches overall.

This is a select-fire airsoft gun with an ambidextrous thumb switch for Safe, Semi and Full Auto. If you are used to the M16/M4/AR-15, the switch is exactly where you expect it to be and the selection works exactly the same way. 

Sights

The MCX Virtus comes without sights. On a gun like this they would be back-up iron sights (BUIS). I will mount a dot sight for testing and, since Sig sent me the Romeo5 XDR, that’s the one I will mount. The gun has a M1913 Picatinny rail that runs 16 inches along the top of the receiver and handguard to augment the M-LOK slots on both sides and the bottom of the forearm. Mounting optics and accessories should prove no problem. Before you go crazy, though, remember that this is a close-quarters battle gun. Sights, a laser and a light are about all you want. Yes, thermal imaging, a rangerfinder and a bipod are nice options, but not when you are clearing rooms!

Magazine

The gun has a 120-round magazine that fits into the receiver just like an AR mag would. The release is in the same place and works the same so, once again, those who are familiar with the Armalite platform will be at home with the MCX Virtus.

Virtus AEG mag speedloader
Virtus magazine above and speedloader below.

Sig gives you a speedloader to fill the mag. The gun is rated for 0.20-gram BBs, and, as I have with other guns, I will test it with different BBs and different weights.

Battery box

Like most stick batteries in full-auto AEGs, the battery on the Virtus lives inside the forearm. Unlike many AEGs, the Virtus forearm slides off easily with the removal of a single captive pin. I have fought M4 handguard keepers for days, trying to install and remove batteries! There seems to be plenty of room inside the forearm of this one for larger batteries, but I have asked Sig if a higher mAh rated battery is acceptable, since they do not want you to use one with higher voltage. I understand the operational difference between volts and amperage, but I still want to hear from them.

Velocity

As it comes Sig rates the gun at up to 370 f.p.s. That would be with the M120 spring installed and using a 0.20-gram BB. Naturally I will test that with a lot of ammo, and then install the M110 spring and test it, as well. It looks like I have a lot of testing ahead of me!

Hop Up?

An airsoft gun in this price range has to have Hop Up. This one is mounted on the steel bolt. Dial the toothed wheel up or down to adjust the backspin on the BB.

And this answers another question — does the dust cover really work? Yes, it does — just like the firearm. The forward assist, however, is just for show. It is spring-loaded but is cosmetic, only. I still remember tap, tap, pull, tap as the mnemonic for a jammed M16 — because in my day they always did.

Virtus AEG receiver
The dust cover is up. At the left you can see the spring-loaded forward assist.

Virtus AEG Hop-Up
Retract the bolt to see the Hop-Up adjustment (arrow).

At what price?

On the Sig website they have the MCX Virtus AEG in stock at the full retail of $459.99. All the dealers I checked with who list them minus the battery and charger for $399.99 were sold out. Hmmm — might there be an axiom there?

Discussion

This is not a kid’s toy AEG. This one is serious, and Sig intended it to be. It’s heavy, solid and cold to the touch. The rest of what it is will have to wait for the next report.

Summary

We are starting to test a real high-end AEG here. This test will be thorough and long, for there is a lot to look at!