by Tom Gaylord
Writing as B.B. Pelletier

Sig M17 Proforce airsoft pistol
Sig M17 ProForce airsoft pistol.

Part 1
Part 2

This report covers:

  • The test
  • Sig 0.20 gram BBs
  • TSD 0.20-gram BBs
  • Move to heavier BBs
  • Valken Accelerate 0.25-gram BBs
  • Air Venturi CQBBs 0.25-gram
  • TSD Bio 180 0.26-gram BBs
  • The Infinity Bio 0.25-gram BB
  • Hop-Up
  • 10 Infinity Bio BBs
  • Summary

You’re gonna get your money’s worth today! Today I start testing the accuracy of the new Sig Sauer M17 ProForce airsoft pistol.

The test

I shot off a rest at 10 meters. The pistol was rested directly on the sandbag. That seemed to work well and I am pleased with the results. I shot different numbers of BBs with different aim points, so I will describe what I did for each target as I go.

Sig 0.20 gram BBs

I started the test with the sample 0.20 gram BBs Sig sent with the pistol. I thought they are too light for CO2, and the velocity test in Part 2 seemed to confirm that, but Sig sent them so let’s see what they do.

I used a 6 o-clock hold for the first two shots that landed very low on the target. I marked them 1 and 2 for you. Then I switched to holding the top of the front sight at the top of the bull. I didn’t mark the first target with the aim points, so I’m telling you that shots 3 through 10 were aimed at the top of the bull. Therefore we can’t measure all 10 shots, because two aim points were used. The last 8 BBs landed in 2.452 inches at 10 meters.

Sig BBs
The first two Sig BBs (6 o-clock hold) landed low and right and I marked them. The next 8 (in the bull) were more-or-less level and slightly right of center.

TSD 0.20-gram BBs

Remember that TSD 0.20-gram BBs are on the light side. With the aim point at the top of the bull they hit high and right. Only 8 are on the target paper, including one way at the top. Those 8 are in 3.179-inches at 10 meters.

TSD Tactical 0.20-gram BBs hit high, relative to the aim point. Eight BBs are in 3.179-inches between centers.

Move to heavier BBs

Okay, I don’t like what I’m seeing so far. I think the CO2 is driving those 0.20-gram BBs too fast. So the next BB weighed 0.25-grams. That would slow things down. I also loaded just 5 BBs for the next target.

Valken Accelerate 0.25-gram BBs

The M17 put 5 Valken Accelerate 0.25-gram BBs into 2.421-inches at 10 meters. That’s more like it! This airsoft gun is not made for shooting at targets; it’s a skirmishing weapon. But you don’t learn about its performance by shooting at life-sized silhouettes!

Valkan Accelerate BBs
Five Valken Accelerate 0.25-gram BBs went into 2.421-inches at 10 meters. These BBs are pure white. The bottle is gray to keep them safe from UV rays. They are also biodegradable, as more than half the airsoft BBs seem to be these days.

Now, I know the M17 can shoot. Let’s look at several more of the heavier BBs. Because the BBs are landing so far below the aim point I will load 6 instead of 5. If one should happen to hit higher, my first shot will clue me and I can change the aim point.

Air Venturi CQBBs 0.25-gram

Next up are six 0.25-gram Air Venturi CQBBs. These are also biodegradable. Six of them went into 3.79-inches at 10 meters, so they are probably not right for the M17.

Air Venturi CQBBs
Six Air Venturi 0.25-gram CQBBs went into 3.79-inches at 10 meters.

TSD Bio 180 0.26-gram BBs

Next up are six TSD 0.26-gram biodegradable BBs. These also went below the aim point, but they did center on the bull. This is the first BB to do that.

The group measures 2.519-inches between centers for six shots, plus it’s the first group to be centered, left and right. Given the imprecise aim point that’s not bad! This is a BB to test further.

TSD 26 gram BBs
Six TSD 0.26-gram Bio 180 BBs went into 2.519-inches at 10 meters. This is the first group that is centered, left and right.

The Infinity Bio 0.25-gram BB

This is the last BB I shot. The Infinity Bio 0.25-gram BB not only went higher on the target; it’s also well centered. This looks promising! Six BBs are in 2.573-inches at 10 meters, with the last five of them in just 1.477-inches! Guys — THIS is a group! This is what I have been hoping for. This M17 is a tackdriver, because I am still guesstimating my hold at the top of the bull. Time for the Hop-Up!

Infinity Bio BB
The lower left hole was the first shot. Then the M17 pounded 5 Infinity Bio 0.25-gram BBs into the bull! Six shots in 2.573-inches at 10 meters, with the last five in just 1.477-inches! This is the BB!


Hop-Up is a generic term for the mechanism that puts a backspin on the BB as it leaves the barrel. That backspin is what makes it fly straight and level farther than gravity should permit.

I have two experiences with Hop-Up. In cheap airsoft pistols you use Hop Up to get the BBs to fly straight. If you don’t they will curve to one side or the other, like a baseball.

In more expensive Automatic Electric Guns (AEG) and in spring-piston sniper guns, Hop-Up makes the BBs fly level longer. It’s how you get the distance.

I had no idea of how the Hop-Up in this M17 pistol worked, except the directions were stamped right on the adjustment. Let’s look.

The Hop-Up adjustment is under the barrel. Rack the slide back to see it. The instructions are stamped on it. Turn it in that direction to make the BB go up.

I adjusted it clockwise as far as it would go, because I had been aiming high and the BBs were landing low. It moved less than half a turn.

10 Infinity Bio BBs

I then shot a group of 10 Infinity Bio BBs, hoping to show you a one-inch group. This time I used a 6 o-clock hold that’s far more precise than guessing where the top of the bull is. The first BB hit at 4 o-clock in the 9-ring and I thought I was in for a ride.

But alas, the other BBs went up high. I had adjusted up too far. And also I guess I was getting tired because my group opened up to 4.279-inches between centers. Phooey! Of course the last 9 BBs are in 2.844-inches, but that’s still pretty large.

10 Infinity BBs
Ten Infinity BBs are in 4.279-inches at the top of the target. Yes, all 10 are on the paper, and the 9 at the top are in 2.844-inches.


This M17 can shoot — and I mean REALLY shoot! The Hop-Up is incredibly precise and I wasn’t anticipating that. I just horsed it around when it wanted some finesse.

The M17 definitely shoots best with 0.25 and 0.26-gram BBs when it’s running on CO2. When I switch to green gas I’ll bet the 0.20-gram BBs will be best.

The sights are not adjustable, but remember what this is. It’s a skirmishing sidearm for shooting at large targets. Today I’m just learning what it likes and how it performs. The sights work perfectly for the purpose this gun was intended.

I think you see where this is going. I have to test this pistol again on CO2, but next time I know which BBs to try and which to avoid. We are gonna have us some fun, guys!