by Tom Gaylord
Writing as B.B. Pelletier

Sig M17 Proforce airsoft pistol
Sig M17 ProForce airsoft pistol.

Part 1
Part 2
Part 3
Part 4

This report covers:

  • SIG ProForce M17
  • The test
  • The BBs I tested
  • Today’s test
  • First up — Sig BBs
  • TSD 0.20-gram BBs
  • Valken Infinity 0.25-gram BB
  • Hand-held
  • Proof of the pudding
  • Summary

I haven’t written a lot about airsoft in the recent past, but this report has turned out to be a pivotal one. Today I will show you proof of the claims I have made about the potential for airsoft accuracy.

SIG ProForce M17

This is about the SigAir ProForce M17 airsoft pistol. It has a retail price of $180, so it’s more than a toy. This pistol is a serious one for serious users, which for a pistol like this are skirmishers first, followed by action pistol competitors. And, lest we forget, it’s also a fine training tool for anyone who carries the firearm. I think you’ll see support for all of that today.

The test

In Part 4 I tested the pistol at 10 meters using the CO2 magazine that comes with it. We saw accuracy as good as 5 shots in about two inches, which Sig confirmed was their expectation. But I have shot a lot of higher-level airsoft in the past and, if there is one thing I know for sure, a gun that’s powered by both CO2 and green gas will usually be the most accurate with green gas. CO2 is just too powerful for the finest accuracy. However, having said that, two inches at 10 meters is more than enough to satisfy this pistol’s performance requirements.

The BBs I tested

I also told you in Part 4 that at the slower velocities green gas achieves we might see a change in the BBs this pistol prefers. From the Part 3 test we had narrowed it down to the Infinity 0.25-gram biodegradable BB and the Valken Accelerate 0.25-gram BB that is also biodegradable. But in Part 4 when I started adjusting the Hop-Up, the Accelerate BB fell by the wayside — leaving the Infinity BB as the clear front runner.

Today I selected the unbranded 0.20-gram BBs SigAir sent with the test pistol, and the 0.20-gram TSD Tactical BBs. At the lower velocity from green gas I wanted to see whether either of these BBs would shine. I also selected the 0.25-gram Valken Infinity BB and the Valken 0.25-gram Accelerate BB, simply to see whether they were still accurate at the lower velocity. I say lower, but in the Part 2 velocity test the 0.25-gram BBs were still shooting at 310+ f.p.s. That’s not really slow in the world of airsoft pistols.

Today’s test

Today I shot the pistol from a bench at 10 meters. I began with the bottom of the pistol grip resting on the sandbag, but I did change holds as the test progressed. I will tell you when that happened.

I charged the green gas magazine with gas after every 10 shots to keep velocity constant, however I discovered something important. I had been charging with the magazine laying on a table and that was giving me a lot of gas blow-by. I felt I was wasting as much gas as I was using. When I picked up the magazine in one hand and held the green gas can in the other my seal became more effective and the blow-by was reduced. There may be more than 10 effective shots on green gas when you fill the mag this way.

First up — Sig BBs

First to be tested were Sig’s unbranded 0.20-gram BBs. On CO2 eight out of ten of these went into a 2.452-inch group at 10 meters. I wasn’t adjusting the Hop-Up when I shot that group, and it was hitting high on the target paper. That other two BBs hit off the paper. In this test I just shot 5 BBs and they landed in a 1.903-inch group at 10 meters — not that much better than the CO2 group that had more shots. This may not be the best BB for this particular pistol.

Sig BB group
The ProForce M17 put 5 Sig 0.20-gram BBs in 1.903-inches at 10 meters.

TSD 0.20-gram BBs

Next I shot 5 TSD 0.20-gram Tactical BBs at the target. The first five missed the target altogether, so I reloaded and shot a second five. I thought they were landing too high, so I held under and indeed they were. A couple nicked the top edge of the target paper.

Once I knew that I adjusted the Hop-Up to lower the rounds, but they still weren’t landing on the paper. I dialed the Hop-Up as low as it would go and even the third set of 5 BBs missed the target paper altogether. At that point I abandoned the TSD BB for this pistol.

Valken Infinity 0.25-gram BB

The next BB I tried was the 0.25-gram Infinity biodegradable BB from Valken. The first 5 I shot gave a group that measured over 2-inches between centers, and that’s when I decided to try a different hold. The first five also landed high on the target, so I adjusted the Hop-Up back down a bit.


This time I held the pistol in two hands in a modified tactical grip, with the left or off hand pressing the pistol back into the right hand. My left arm rested on the sandbag for stability, but the gun was ahead of the bag and didn’t touch it. And here it is, guys! Five shots landed in 0.8-inches at 10 meters. Now, THAT is what an accurate airsoft pistol can do!

Infinity BB group 1
This, ladies and gentlemen, is what an accurate airsoft pistol can do! Five Valken Infinity biodegradable 0.25-gram BBs went into 0.80-inches at 10 meters. This isn’t the 5 meters at which we shoot BB guns. This is a full 10 meters, which is 33 feet.

Proof of the pudding

When I saw that group I decided not to test the other Valken BB. The Infinity is the BB for this pistol for both CO2 and green gas. I was tiring from firing a lot of shots by this point in the test, but I had to know that this tiny group wasn’t just a fluke. It is only 5 shots, after all. I had to know if this group was representative.

Since the last group hit a little low on the target I adjusted the Hop-Up back up about 1/6 turn. And that moved the center of the next group up by 3-3/4-inches at 10 meters. So — with this BB the Hop-Up adjustment is super responsive!

The second group measures 1.21-inches between centers. That is larger than the last one, but it’s still quite small when SigAir says to expect 2-inch five-shot groups. Ladies and gentlemen, I think we have discovered the best BB for the M17, and it’s the best with both power sources, which makes it even better.

Infinity BB group 2
The second time I tried a 5-shot group with the Infinity BBs five went into 1.21-inches at 10 meters. This is the BB for this pistol!


I gave the SigAir ProForce M17 airsoft pistol a very thorough test and discovered a lot of things. First of all, it is super realistic. And that is exactly what a skirmisher or someone using it to train with wants. The heft, the look and even the weight are all spot on. For those who live in areas where it is impossible to own the Sig firearm, this is as close as you can get — which is exactly the point of the whole airsoft industry!

Next let’s talk about the trigger. I own the Sig P320 M17 9mm firearm and can tell you that the trigger on this pistol is better than the one on that handgun! The two are very close, but the edge definitely goes to this airsoft gun.

While SigAir recommends 0.20-gram BBs for this pistol, I found that this one I’m testing works better with 0.25-gram BBs, and that was with both gasses. Specifically, I found that Falken Infinity 0.25-gram biodegradable BBs worked the best.

Infinity BBs
Just so you know — these are the BBs that did the best in all my tests.

In today’s test I discovered that the M17 likes to be hand held. I had tried that previously, but not the way I tried it today. Today’s hold was more of a tactical hold and it was rock-solid.

The Hop-Up on this pistol really works well! Over the years I have used all kinds of Hop-Up mechanisms. Some control the flight of the BB in all directions, and the guns that do that usually shoot their BBs to the left or right until they are adjusted. The Hop-Up in the ProForce M17 works to raise or lower the strike of the BB. There is a tiny bit of left and right movement as you adjust up and down, but it is so small that it doesn’t look intentional. The pistol shoots pretty close to center anyhow, so up and down are all you need. Just remember what I said if you get one — this Hop-Up is really sensitive.

As far as gasses go I think SigAir got it right. For skirmishing, where you want a lot of shots with decent accuracy, CO2 is more desirable. For training you also want a realistic number of shots and the M17 mag duplicates the number of cartridges held by a standard mag in the firearm. Therefore CO2 is the gas most people will want most of the time. The slight accuracy edge of green gas will not matter to either discipline, so use the gun straight out of the box and forget about the green gas mag.

On the other hand, for action pistol shooting, where accuracy is more important, go with the green gas mag. Get additional mags so you can swap during a match course and I think you can count on 15 good shots if you take my advice about using your hands to hold the gun when filling.

If airsoft intrigues you, this is a good pistol to watch!