Secrets Of SIG Airguns – Part Three, Trigger And Pellet Loading

For Part Three of our HAM series on Secrets Of SIG Airguns – we look at the trigger and pellet loading mechanism.

In Part Two of this series, we saw how complex the SIG air rifles action looks. In fact, most of that complexity is due to the trigger and pellet-loading mechanism, as we’ll see today.

All SIG long guns to date use a similar form of belt-fed pellet magazine. It’s getting this belt to rotate and bring the next pellet into battery every time the trigger is pulled that makes the action so complicated.

Secrets Of SIG Airguns

HAM fundamentally disagrees with SIG’s claim that its air-powered long guns have a semi-auto action.  This claim is made only on the back of the retail box where – possibly – it might impress purchasers in “big box” retail stores.

However, it’s not correct. At least in the normally-accepted meaning whereby the firing of a shot automatically chambers the next round, that is.

The SIG  air rifles may FEEL like a semi-auto, but they actually uses a double-action revolver mechanism to advance the next pellet. That’s why the trigger pull weight is so heavy. It’s also what we will explore today.

The Trigger And Pellet Loading Linkages

We’re covering these together as it’s really impossible to separate one from the other. That’s another of the secrets of SIG Airguns.

Believe me, I’ve complained about the trigger feel on SIG long guns. But when you look at the complexity involved and the number of pivoting parts that move every time you pull that trigger, it’s amazing that it feels as good as it does!

Secrets Of SIG Airguns

If you look up inside the open magazine well, it’s easy to see that pulling the Canebrake’s trigger operates a lever that engages the toothed magazine belt and rotates it by one chamber. That’s DA revolver operation and it’s the same as is used in all SIG’s pellet guns.

Below we see the trigger linkage in the Virtus. It’s the same for the Canebrake.

Secrets Of SIG Airguns

The linkage from the MPX/MCX triggers is similar, but not quite identical, as we can see below. Note how the magazine well lips differ between the two designs.

Secrets Of SIG Airguns

In the end, that pull on the trigger releases the hammer – as you would expect. It also continues through the action to operate the mechanism in the top of the gun that advances the pellet belt inside the magazine.

Below we see this mechanism for the MPX/MCX. Not readily visible in these photographs is the fact that moly was applied carefully during manufacture to critical pivot points to ease the action.

Secrets Of SIG Airguns

Below we see the same assembly for the Canebrake/Virtus implementation. You’ll notice some subtle differences in the parts arrowed.

Secrets Of SIG Airguns

So what happens when you pull the trigger? Here we really see one of the secrets of SIG Airguns!

Secrets Of SIG Airguns

Wow! parts and linkages are moving in all directions when the gun is fired! This diagram shows a MCX, but the Canebrake/Virtus mechanism is similar, too.

Who would believe that all that activity was taking place inside the calm, unruffled exterior of the air rifle?

Now I’ve been among those calling-on SIG to improve the functionality of their long guns. For example, ambi mag releases, operating ejector port covers, actuating forward assists.

But – once you look inside these guns – it’s entirely clear that these these things are never going to happen. There’s just no room inside those sideplates!

Check out the other parts of this series from these links: Part One. Part Two. Part Four.

SIG Sauer MPX Pellet Rifle Gen 2, Black 0.177
SIG Sauer MCX Pellet Rifle Gen 2, Black 0.177
SIG Sauer MCX Rattler Canebrake CO2 Pellet Rifle 0.177
Sig Sauer ASP MCX Virtus PCP Air Rifle 0.22