SIG Air ASP20 Air Rifle Technology Overview Part Two

In Part One of this technology overview on the SIG Air ASP20 Air Rifle, we covered the lock-up and cocking effort.

This time, we’ll cover the trigger and barrel.


Of course, one of the big questions with any airgun is “Is it accurate?”. Of course, we’ll find out the answer to this in a comprehensive HAM test review as soon as we receive a SIG Air ASP20 air rifle to test.

However, the image above gives an indication of what to expect. It’s a target I shot with a .22 caliber ASP20 at the SIG press event. The range was 25 Yards.

This target shows the impact from five shots. Three were with JSB pellets. The result was three shots through just about the same hole. Then I fired two more using the SIG Crux pellets. Again, both through the same hole, but with a slightly different point of impact from the JSBs – as you would expect.

That’s as good as I can shoot anything. And I’m definitely NOT a break barrel shooter!

3. Barrel

Ed Schultz from SIG told us that they made a wide search to source barrels for the SIG Air ASP20 air rifle. In the end they decided to manufacture their own. As SIG SAUER manufactures great barrels for firearms, this was a very logical step for the new airgun.

That’s Ed, below, explaining about the ASP20’s barrel.

SIG Air ASP20 Air Rifle Technology Overview Part Two

So barrels for the ASP20 are being manufactured by SIG in New Hampshire. They’re manufactured on the same machines that are used for firearm barrels. And they have rifling of SIG’s own design.

The company says that this rifling has two design goals. One is to minimize unnecessary distortion of pellets. The second is to create a highly effective seal on the pellet skirt.

SIG Air ASP20 air rifle barrels are button-rifled, Ed told me. They have 12 lands and a twist rate of 1 in 450mm (17.72 inches). The barrels are air gauged and SIG Air undertakes a bore scope inspection on every single ASP20 barrel!

In addition, the silencer housing is laser welded onto the barrel to reduce the potential for distortion that could occur with other welding techniques.


4. Trigger

There’s no doubt about it. A huge amount of time and effort has been put into developing the trigger for the SIG Air ASP20 air rifle.

It’s called the SIG ASP Matchlite trigger and it has some unique features. SIG is applying for two Patents in the trigger assembly alone – that’s how unique it is.

SIG Air ASP20 Air Rifle Technology Overview Part Two

The trigger blade itself is based on that of the SIG SSG3000 centerfire rifle. It’s manufactured from an advanced nylon polymer over-molded onto a zinc bearing sleeve. SIG says that this reduces weight and friction, as well as providing improved balance.

Just don’t call this a plastic trigger blade!!!

Below, Ed Schultz discusses trigger functionality.

SIG Air ASP20 Air Rifle Technology Overview Part Two

Design goals for the Matchlite trigger were for it to be safe and provide a clean break. It would also allow the owner to customize the feel over a wide range of adjustment.

The result is a trigger with a manual safety that’s operable from either side of the gun. It also has an adjustment mechanism which is – to my knowledge – unique on spring/piston and gas ram airguns.

The trigger of the SIG Air ASP20 air rifle is adjustable in 2-ounce increments between 2.5 and 3.5 Lbs. There are 8 distinct settings selectable using a screwdriver. Adjustment is made using a ratchet system with individual clicks.

There’s an unusually long spring around the trigger adjustment strut to provide this range of adjustment capability. Importantly, no parts need to be removed from the ASP20 to make these changes.

Controlled by a single screw, these adjustments change not only the trigger pull weight but the pull characteristics also. Ed Schultz explained that the ASP20 trigger can be adjusted to give single or two stage operation, or a point in between.

SIG Air ASP20 Air Rifle Technology Overview Part Two

The trigger weight adjustment assembly is indicated by the number 1 in the CAD visualization above.

Another key feature is that – unlike most other triggers, the SIG Air ASP20 air rifle trigger cannot be adjusted out of its safe tolerance range. A bracket assures the minimum sear engagement required for safe trigger function. That’s indicated by 2 in the diagram.

Certainly the trigger of the SIG Air ASP20 air rifle I shot felt very good. And the other attendees at the press event all agreed.

SIG Sauer ASP20 Gas-Piston Breakbarrel Air Rifle, Beech
SIG Sauer ASP20 Gas-Piston Breakbarrel Air Rifle, Synthetic