Secrets Of SIG Air Rifles – Part Four, The Barrel

For this final part of the HAM series Secrets of SIG Air Rifles, let’s look at the barrel and how it is fitted to the action.

It’s no secret that SIG long guns started-out with rather indifferent accuracy. You can see that in the test targets from HAM’s 2016 review of the MCX. But accuracy has improved dramatically in recent years, as our tests of the Canebrake and MCX Gen 2 demonstrate.

So what’s happened?

Well, one thing is that the company has worked hard to improve the inherent accuracy of the barrels on these guns.

Secondly, they have increased the barrel diameter on the Virtus and Canebrake to 11 mm. While still on the slim side, this is a large  (40+%) increase compared to the 7.5 mm diameter of the MPX/MCX “soda straw” barrel.

Secrets Of SIG Air Rifles

This increase in barrel diameter is important in reducing barrel harmonics when the gun is fired. It’s also valuable in improving shot-to-shot consistency for accuracy.

Next we move to how the barrel is retained in the action.

As we can see in the photograph below, the MPX/MCX have the barrel supported along an approximately 38 mm length of the frame.

Secrets Of SIG Air Rifles

In the Canebrake and Virtus, that length has increased to 62 mm – an increase of over 60%. That alone makes it likely that the barrel will fit more securely and sturdily in between the sideplates. Another plus for accuracy!

Secrets Of SIG Air Rifles

In both designs, the barrel actually clamps tightly into position. A screw on the end of the barrel creates the tension as it rotates.

So that’s the end of this four-part Hard Air Magazine series on the secrets of SIG Air Rifles. I hope that you’ve learned a lot and have learned to appreciate these guns rather more. I certainly have!

But again I must stress, this is NOT a repair guide to these guns. As you can see, they’re very complicated, so I strongly suggest that owners do NOT attempt to repair long SIG airguns. They require very careful disassembly and re-assembly.

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

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