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Education / Training Sig Sauer P365 air pistol: Part 2

Sig Sauer P365 air pistol: Part 2

by Tom Gaylord
Writing as B.B. Pelletier

Sig P365
Sig Sauer P365 BB pistol.

Part 1

This report covers:

  • The test
  • Realism
  • Fresh CO2
  • Oiled the pistol
  • Hornady Black Diamond
  • Sig BBs
  • ASG Blaster BBs
  • Daisy Match Grade Avanti Precision Ground Shot
  • Nature of CO2
  • Shot count and blowback
  • Trigger pull
  • Installing the CO2
  • Summary

Today we look at the velocity of the Sig P365 Air Pistol. If you’re new to airgunning you need to know that CO2 responds best to two things — high temperature and a long barrel. The temperature was fine when I tested the gun (74 degrees F) but we are dealing with a compact pistol whose barrel has to be short. That will affect the power of any CO2 pistol, regardless of the maker.

The test

I shot through the chronograph at 2 feet distance from the start screen. I waited a minimum of 10 seconds between shots in today’s test. Sometimes the wait was much longer but it was never less. Later in the report I will address why this is necessary.


I have told you how realistic this pistol is. I still have to check the gun every time I handle it because my 9 mm P365 that is always loaded is in my office all the time. It would not do to pick up the wrong pistol!


Fresh CO2

For this test I loaded a new CO2 cartridge. I always put a drop of Crosman Pellgunoil on the tip of each new cartridge before piercing it. When the cartridge is pierced the oil is blown into the valve and it gets on all the o-rings and seals inside. It keeps them fresh and doing their job. At the end of the report I have an important message about piercing this pistol, so don’t miss it.

Oiled the pistol

I talked to Ed Schultz of Sig regarding the P365 and he told me this BB pistol tends to run dry. Oiling some key points will help ensure smooth reliable operation. Just pull the slide as far back as you can and hold the pistol upside-down to access the oiling spots under the slide, as shown in the photo below that Ed sent me.

P365 oil
From Ed Schultz to you. These are the 4 places to oil the P365 slide periodically. Also oil each new CO2 cartridge.

Ed says Sig is looking into an oil they can sell for this purpose, but for now you can use a 20-weight non-detergent motor oil that has an o-ring conditioner in it. Crosman Pellgunoil is a good choice!

Hornady Black Diamond

First up was the Hornady Black Diamond BB. The P365 magazine holds 12 BBs, but I loaded just ten for this test. That way I can test the magazine hold-open function as well.

Ten Black Diamonds averaged 298 f.p.s. Since these were fired first there was a broader spread of velocities. The low was 287 and the high was 319 f.p.s. — shots one and two, respectively. That’s a spread of 62 f.p.s. The average was pretty close to where it should be, even though the extremes are far apart. It’s listed at a maximum of 295 f.p.s. and that’s what this one gets. And, the magazine hold-open works exactly as it should. I will tell you in a bit why the spread was so large.

Sig BBs

Sig doesn’t make BBs — yet. So they don’t have their own brand of BBs to sell, but they do include a small plastic packet of steel BBs with each gun. So I tried them. They averaged 299 f.p.s. with a spread that went from 293 to 305 f.p.s. That’s a difference of 12 f.p.s. Now that the CO2 gas in the cartridge is being used the gun is settling down. Often the first couple shots after piercing a cartridge have liquid CO2 in the valve that bollixes up the velocity, as you saw in the first string.

ASG Blaster BBs

Next I tried 10 ASG Blaster BBs. They averaged 299 f.p.s. with a low of 293 and a high of 304 f.p.s. The spread was 11 f.p.s. That’s close to the Sig BB performance. I’m not saying Sig rebrands those particular BBs — just that all steel BBs perform about the same in this pistol, once it settles down. So the Hornady BBs would also be like these is I hadn’t fired them first.

Daisy Match Grade Avanti Precision Ground Shot

The last BB I tested was the Daisy Match Grade Avanti Precision Ground Shot. For this one I am going to show you the entire string — shot-by-shot.

2…………did not register

It’s pretty obvious what happened in this string. These BBs started out just as fast as the first three, then around shot number three the liquid CO2 ran out and only gas was left in the cartridge. That’s when the velocity starts to drop. Let’s see why.

Nature of CO2

CO2 develops pressure when the liquid inside the cartridge flashes (evaporates rapidly) to gas. At 70 degrees F its pressure is around 850 psi when it is contained in a vessel with no escape. But, as it evaporates while the gun is shot, it cools the surfaces of the gun that it comes in contact with, which is all of the gas chambers and ports inside the gun. In turn this lowers the temperature and also the pressure of the CO2 gas, resulting in lower velocity. That’s why I wait at least 10 seconds between shots — to allow the gun to normalize and not cool down too much.

Shot count and blowback

I had heard somewhere that the P365 gets about 40 good shots per CO2 cartridge and this test bears that out. The slide is small so it’s also light, so the blowback isn’t as strong as with some larger pistols. Still the slide does move all the way back and you do feel it.

Trigger pull

The trigger has a light pull with some travel. It feels like a double action pull because of the travel. To begin shooting you have to cock the hammer by pulling back the slide unless the slide is already locked back and you just release it after loading a fresh magazine. The trigger pull is a surprisingly light 3 lbs. 13 oz. Several times the pistol surprised me by firing before I was ready. I’m glad that happened when the BB trap was only three feet away and not when I was shooting at a target! I’m making a note to myself to respect this light trigger.

Installing the CO2

I purposely waited until now to discuss this procedure so it doesn’t get overlooked. The P365 pierces the CO2 cartridge when the magazine cap is screwed down, like many gas pistols. But, there is a thick face seal (where the flat end of the cartridge bears against as it is pierced) in this magazine and the CO2 will leak out until the cap fully compresses it — so there is a special knack to piercing the CO2 cartridge in this pistol. The first couple cartridges I installed lost a lot of gas before I got them sealed.

The trick is to screw the magazine cap down until it’s tight against the cartridge. Then hold the magazine body in one hand and the Allen wrench in the other hand with the hands rotated so that relaxing them would give the end cap almost a full twist. When you do this, just let each hand go its way and finish screwing the end cap down. The CO2 will hiss for an instant if you do it right and you won’t lose much gas, if any.

P365 gas
To pierce the CO2 cartridge quickly, hold the magazine in one hand and the Allen wrench in the other in such a way that the hands move in opposite directions to screw the cap down rapidly.

Once I did this, the cartridge was pierced just as quickly as any air pistol could. When I did the velocity and shot count test the cartridge was pierced this way, so no gas was lost.


It’s been fun getting acquainted with this little BB pistol. Because I am so familiar with the firearm already, I felt I was shooting with an old friend.

Accuracy comes next, but that isn’t the final report. I then want to talk about using this airgun and others as a self-defense training tool. I will show you my carry holsters and discuss how I use the gun to train. Until then!

author avatar
Tom Gaylord (B.B. Pelletier)
Tom Gaylord, also known as B.B. Pelletier, provides expert insights to airgunners all over the world on behalf of Pyramyd AIR. He has earned the title The Godfather of Airguns™ for his contributions to the industry, spending many years with AirForce Airguns and starting magazines dedicated to the sport such as Airgun Illustrated.

31 thoughts on “Sig Sauer P365 air pistol: Part 2”

  1. B.B.

    ” bollixes up the velocity”, new one on me mate?
    CO2 cartages always seemed like a recycling nightmare, so I never got into them. Plus my parents may have been afraid that my brother and I would make, or at least try to make bottle rockets…


  2. B. B.,

    The trigger pull of this pistol if comparable to the firearm may make this a poor choice as a carry gun unless the trigger is a little heavier. I don’t get armchair defense people when they want a hair trigger on a pistol that is going to be used in a high adrenaline situation. Since you yourself experienced a few accidental discharges this is definitely a pistol that should be carried by people who are willing to train in properly carrying this.


  3. Everyone,
    I don’t know if anyone follows Rick Rehm (Shooter1721), but check out this video of him doing an unbelievable trick shot using a Taipan Veteran Standard .22 cal bullpup PCP. He is shooting offhand at 100 yards. He has two balloons on either side of a Rambo knife and he hits the knife’s edge, splitting the pellet, and bursting both balloons. I just can’t believe he was able to do that, amazing shooting.

    • Geo
      Does it say how many months he has been trying before he made the shot?

      And in reality. I guess it could be done. Remember if the pellet hits with enough energy it will fragment. It don’t take much to pop a balloon.

      I didn’t watch the video. But the trick part of the shot is hitting the blade. Chris and I have held 13/16’s ten shot groups at 100 yards with our .25 Marauder’s. So I would say if we had a Rambo knife out there at the 100 yards we probably eventually would make a hit. Then the other trick would be getting the pellet fragments to pop the balloons.

      Now throw off hand in the equation and I’m going to call it more luck involved.

      Why don’t you reply to the video and ask how long it took him.

      I may be totally wrong and missing something. But eventually he would hit. And eventually I’ll win the lottery big time. That’s if I can keep playing throughout eternity. 😉

      • He’s done a lot of trick shots with airguns. He also shoots in many airgun competitions. He’s no joke, this guy can shoot. I didn’t count the number shots it took, but it was less than one mag. He did some videos a while back reviewing the JSB Hades pellets, which was interesting as well.

        • Geo,

          If you post it,…. I watch it. 🙂

          Since you make the rounds on other sites,…. it would be nice to find them all in one place. That would be a nice site (for sure) for those that are time challenged.

          I really just need to hit them all,… save them,… and just click down the saved list. Problem is,… I would have a tuff time keeping up with regular viewings of all the latest post. I am lucky to do this one during the work week. 🙁


          • Chris,
            I understand, it does take a lot of time keeping up with these things. I have subscribed and clicked on the notification bell on several airgun sites, and computer sites too. I get emails with the notifications of newly available YouTube videos. If it is one that I might be interested in watching, I leave the email in my inbox. If it is a video I am not that interested in watching, I just delete the email.
            I just took a couple of days upgrading a laptop mechanical hard drive to a solid state drive. That took longer than I expected, and I fell behind on the blog :(, but I am caught back up now 😉 I only post videos that I think might be of interest to you guys in the blog.

  4. B.B,

    Based on your first review, I ordered one of these during the Labor Day sale (it is on back order). I am really looking forward to getting it and testing it out.

    I am curious what your thoughts are on using either Dust Devils or Smart Shot BBs in this pistol, especially in training situations. Any idea if those would work, or reasons why they wouldn’t work? I know the FPS will be very different from steel BBs due to the weight differences, but mostly I am curious about whether they would function or not.

    Thanks for all you do on this blog!


  5. B.B.
    I have a question for you. I am rebuilding my fifty year old Crosman 147 muti-pump. What would be the best lubricant to use on the insides and O-rings when re-assembling? I have silicone grease and also Pellgunoil. The rebuild kit just arrived today so I will be re-assembling before too long. Thanks.

        • Geo,

          Glad to hear you are going to get the old Gal repaired. After our earlier discussions, I found some of my repair manual info on the 147. I can email you a copy if you want one.


          • Benji-Don,
            Sure, I’ll take any information I can get. I have a Crosman Authorized Service Manual. It had an important step missing between step 6 and step 7. It did not mention that the locating screw (the one that holds the stock to the action) had to be removed in order to remove the valve assembly. I saw it mentioned on a YouTube video, so I became aware of that. The screw has no flats or anything to wrench it out. I used a drill chuck to clamp onto it and was able to remove it without scarring anything up. I am looking forward to the re-assembly of her. Thanks for the offer to send the repair manual. It may be the same one I already have, but maybe it’s not.

  6. BB,

    If I were to buy one of these guns, and I suspect that I will at some point, it guess it will become more obvious what area I am looking at in your lubrication point photo, but in the meantime I’ll just ask. Is the gun pointing at the ground, revealing the underside of the slide’s rear section in that photo?

    I’d also like to know if this gun is based on one of Sig’s other BB guns that might benefit from lubrication at the same points, if you know.


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