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CO2 The first Smith & Wesson 78G air pistol(s): Part 2

The first Smith & Wesson 78G air pistol(s): Part 2

by Tom Gaylord
Writing as B.B. Pelletier

S&W 78G
A very early S&W 78G air pistol. Though the picture looks matte because of lighting, this is one with glossy paint. It’s like new!

Part 1

A history of airguns

This report covers:

  • Oh, oh!
  • BB is fine
  • Parallax!
  • Peep sight
  • Back to the S&W 78G
  • Velocity
  • Power adjuster
  • Hades string two
  • My other 78G
  • Crosman Premiers
  • Low power setting?
  • Trigger
  • Shot count
  • One final test
  • Summary

I mounted the UTG Micro Reflex dot sight on the IZH-61 and prepared to shoot it at 10 meters, rested. I had to remove the front sight so the dot had a clear view of the target. The rear sight was just adjusted as low as it will go and was out of the way.

Oh, oh!

BB has slipped a cog everyone! He hasn’t even read the title of his own report!

BB is fine

No, BB hasn’t slipped a cog. He spent 90 minutes with the IZH-61 this morning, trying to shoot groups with a dot sight and failed to do so. His failure is your benefit, because he has some interesting information to share.


The IZH-61 I’m testing only has an 11mm dovetail at the very rear of the receiver. When I mounted the UTG Micro Reflex dot sight there it had a huge problem with parallax. Remember my report on the Romeo5 dot sight earlier this week? Some of you asked me what the advantages were and I said less parallax was one. Well, the UTG sight has a holographic screen and, when it’s mounted close to your eye, there is a lot of parallax. In all my testing of that sight on other airguns I have mounted it about 12 inches or more from my eye and the parallax was not noticeable, but this time the sight was three inches away and it was. The best I could do with RWS R10 Match Pistol pellets was 5 in about two inches. I’m not showing that group because it isn’t helpful.

Well, I gushed all over that Romeo5 sight from Sig. Why didn’t I mount it on the 61? I tried but the Romeo5 only mounts to a Picatinny base. Well, doesn’t UTG make an adaptor for converting those to 11mm dovetails? Yes, they do. And would you believe it — that adaptor will not fit the base of a Romeo5? It fits but the place Sig has put the Picatinny key in the base of the Romeo5 has the adaptor sticking halfway out the back.

Peep sight

I have a great idea! I’ll mount a peep sight on the rifle and try again. Why didn’t one of you readers suggest that? 😉

I’m now two hours into my day with nothing to show for it. I gotta move on! What about that pretty S&W 78G I told you about? Great idea.

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Back to the S&W 78G

BB’s back on the rails. Yes, this report really is about the 78G.

I had put a new CO2 cartridge in the pistol last week and today it was near empty! The gun has just been resealed. We know the early pistols were troubled with porous frames that leaked down slowly. Is it that or is there something else? Just to know for certain I lubed the fresh CO2 cartridge with ATF sealant. At the end of this report I will tell you what I’m going to do with that.


I started testing velocity with the JSB Hades pellet for no particular reason. The first 10 shots gave an average 326 f.p.s. The spread went from 316 to 339 f.p.s. That’s a difference of 23 f.p.s. But it’s also pretty low! I expected something in the 375 f.p.s. region. The Hades weighs 15.89 grains, so its a heavy middleweight .22 caliber pellet. At the average velocity this pellet generated 3.75 foot-pounds at the muzzle.

Power adjuster

One thing the 78G has is an adjuster for power. It’s a screw that increases and decreases tension on the hammer spring. Being an airgunner, I cranked it in (up) as far as it would go and shot a second string of Hades pellets.

Hades string two

This time Hades pellets averaged 353 f.p.s. from the 78G. The low was 342 and the high was 365 f.p.s. — a difference of 17 f.p.s. So, it got faster and also more consistent. At the average velocity the Hades generates 4.4 foot-pounds at the muzzle. Yes, the power adjuster works. And yes, the 78G in factory trim is not a magnum air pistol. 

My other 78G

I reported on my other S&W 78G many times. Most recently I tested it for velocity and, while I didn’t test with Hades pellets, I did test it with Crosman Premiers, however, and got an average of 480 f.p.s. That pistol has been hot-rodded, so it’s faster than a stock 78G. Let’s see what this current pistol does with Premiers.

Crosman Premiers

The pistol being tested today averaged 355 f.p.s with Crosman Premiers. The low was 352 and the high was 358 f.p.s.. That’s a spread of just 5 f.p.s. So this pistol in stock trim is very consistent with Premiers. And we can see the marked difference between this stock pistol and my hot-rodded one. At the average velocity Premiers generated 4 foot-pounds exactly.

Low power setting?

The S&W 78G does not have a low-power setting. When you cock it there are two clicks but the first one is only to set the sear. I tried firing it and the pellet did not come out of the barrel.

I actually read in the owner’s manual what the first click is for. Yes, I have a manual and yes, I did read it!


One of the very nice things about this early 78G is it has an adjustable trigger. When I got it the trigger had a two-stage pull that took 2 lbs. 12 oz. for stage one and 3 lbs. 8 oz. for stage two. It felt heavier than that. And stage two had some noticeable creep.

I adjusted it by the book and stage one still took 2 lbs. 12 oz. But stage two now breaks at 3 lbs. 1 oz. and the break is clean. All the creep is gone.

So the big question is — how does this trigger compare to a Crosman Mark I trigger? I have to say they are about the same. The Mark I trigger is shaped better for my finger because it’s not as curved. But the release is pretty much the same. The Mark I release can be adjusted lighter, and I guess that is better, but only by a slim margin.

Shot count

I was curious about how many shots there are on a CO2 cartridge, and we know the number will vary somewhat from cartridge to cartridge. The CO2 guns of the 1950s got around 30 shots to a cartridge, but we were dealing with the old Crosman “bottlecap” cartridges that had a high leakage rate. Today’s cartridges do not leak down unless the gun they are in has a problem.

At this point in the test there were 35 shots on the cartridges since new. The extras were from testing the trigger pull. So I shot another string of Crosman Premiers and this time the average was 369 f.p.s — an increase of 14 f.p.s. from the previous string. Wow! The low for this string was 366 f.p.s. That’s 8 f.p.s. faster than the fastest shot in the previous string of Premiers. This pistol is waking up! The high was 373 f.p.s., so the spread for this string was 7 f.p.s. So the 78G is still very consistent with Premiers.

Next I shot a 10-shot string of Hades pellets and got an average 354 f.p.s. That’s just one f.p.s. faster than the previous string of Hades. The low was 348 and the high was 361 f.p.s. so the spread was 13 f.p.s., compared to 17 f.p.s. before. 

At this point in the test there were 55 shots on the CO2 cartridge. Now I shot another string of Premiers. The first shot (shot 56) went out at 374 f.p.s. — the fastest speed I recorded in this test. Shot 64 was 365 f.p.s and shot 65 was 359 f.p.s. I was pretty sure at that point the cartridge had run out of liquid CO2 and was now running on fumes. Here are the remaining shots — still with Premiers.


I stopped shooting pellets and fired 14 more blank shots before the gas was gone. For a 1971 CO2 gun, this is a pretty good performance!

One final test

Remember what I said at the start of this report about the gun leaking down in a week? I want to test that to see if this pistol has a porous frame. Since I had oiled it with ATF sealant I knew the seals were working as they should, so I installed a fresh cartridge in the pistol and put it back into the box. The next time I test it, it either will or won’t have gas. It shouldn’t matter if that’s a week or a month from now.


I gave a lot to get this pistol because I wanted to test a stock S&W 78G. Having done that for velocity and also having adjusted the trigger as nice as it will go, I’m now interested in the accuracy. That’s next!

40 thoughts on “The first Smith & Wesson 78G air pistol(s): Part 2”

  1. BB,

    It really is a nice looking air pistol. The Alpha Proj may have been based upon this. That ATF sealant may help seal a porous body also. It will get sucked into the leakage areas (hopefully) and could fill in the pores. You may have to do it more than once.

    That is nice to know about with that UTG dot sight. I plan on getting one in the future and knowing I need to mount it as far away as possible is a good thing.

      • BB,

        Over the years I have had experience with many varieties of dot sights. Most have been very disappointing. Knowing of a good, affordable dot sight and also knowing it’s weaknesses is invaluable.

        My absolute favorite dot sight was the Weaver Quick point.

  2. I am sure I am not the only one in this boat, but I wish I had learned some of the things I have read here years ago. I bought an old lever action BB gun many years ago at a yard sale that leaked CO2. I couldn’t find any parts for it, so I sold it. Now I really wish I had kept it just because I liked shooting it and it was a cool gun. And, I would have liked to try the ATF sealant trick.

    Live and learn.


  3. BB ,

    I thought the readers would want know where to find parts for this pistol . Baker Airguns has a kit with the firing valve included . It looks like a Delrin type valve , definitely last longer than the OEM valve. I have repaired a few of these and they are nice shooters .

  4. Captain Bravo ,

    The internet has changed things allot , not necessarily for the better !! The one good thing is the ability to find parts . I have found parts for AH Fox shotguns and Le Fever shotguns. Where 20 years ago You would have to write or call the Fox collectors association or hope to find something in the Shotgun News classifieds . It is also good to research how to things , You can get an idea if You will be comfortable tearing in or sending it away for repair. In the last couple of years I have repaired a Ruger original 44 carbine and a HK4 that had missing and broken parts . Both obsolete guns with no OEM source for parts . In the airgun world it allows us to find parts for our old vintage guns easily .

    • This was several years ago, but if I had it to do over again, I would try it even if I couldn’t find parts. I now have many more projects under my belt including rebuilding automatic transmissions. After that, I am not afraid to tackle much of anything now. Too late for my BB gun unfortunately.

      Thanks Gene.


    • RR,

      From the Daystate Owner’s Club site,…. it will be at a (later time in the year). But yes,… that is a huge event. I think things will be getting worse before they get better. This will affect (many) things,… as it already is.

      At this point,… each company will have to roll new stuff out on their own,… through other media outlets. I am pretty sure that they are not willing to sit on stuff another 6 months when it is ready to go now. They will find a way.

      And, China being who they are,…. would care more about getting factories back up and running sooner rather than later,……….. ignoring? facts that might dictate otherwise action,…… furthering the virus (at least there anyways),… which will further impact worldwide products even longer.


      • Chris,

        I wish no one to suffer, well maybe those causing the suffering.

        China can go sell their stuff to the rest of the world. We will be better off without doing business with them. It will be rough for awhile, but we will be better off for it.

  5. B.B.
    Thanks for today’s report. I saw a few typos as I was reading through it, so thought that I would point them out so you can clean up your report. Feel free to delete this comment as it’s only for you.
    Parallax!: When I mounted the UTG Micro Reflex dot sight there is (it) had a huge problem with parallax.
    Peep sight: A smiling emoji goes here, if I only knew how. FYI, type : then ) like this 🙂 & for a wink type ; and ) 😉
    Shot count: The CO2 guns of the 1950s got around 30 shots to a cartridge, but were (we) were dealing with the old Crosman “bottlecap” cartridges that had a high leakage rate.
    One final test: The next time I test it, it either will or won’t has (have) gas. It shouldn’t matter it (if) that’s a week or a month from now.

  6. “Remember what I said at the start of this report about the gun leaking down in a week? I want to test that to see if this pistol has a porous frame.”
    Way back on my first job out of college, I worked at a small microwave components house up in Maine. We had some parts that had to be pressurized to 30 psi, but their castings were porous so they leaked like crazy. We had to immerse them in some kind of sealant (I wish I could remember what, but that was 40 years ago!), then let them dry for a couple of days, and after that, the held pressure just fine. But I guess it would be a real hassle to do something similar to this pistol; you’d have to strip it down to the bare bones!
    Hoping the frame is not porous,

    • “We used some of their stuff for pressurized Wave Guides and TWTs to good effect.”
      Shootski, cool! I worked on waveguide components for over 20 years! =>
      Happy weekend, fellow waveguide worker,

      • Dave,

        “Happy weekend, fellow waveguide worker,”

        I’ll go for the happy weekend! As far as worked…I was more of an unhappy user…! We did bang them around on and off aircraft carriers as well as a general difficult environment so we had lots of leaks! So involuntary worker would work 😉


  7. BB,

    I have a couple of recoiling replica CO2 handguns that I have been thinking about outfitting with dot sights and one of the the big reasons, apart from the fact that my eyes are old and can only focus on one plane at a time, is because I thought dot sights were parallax free. I’m thinking that, to avoid messing up the recoil impulse and causing jams in the lower powered application, I will be looking a SMALL dot sights that also seem to be the more expensive ones. For that reason I want to be pretty sure that they will work for me before I buy them or even get too involved in shopping comparisons, for that matter. I guess my question is, is parallax just an issue with rifle mounting a dot sight and does the fact that you have your arms extended way out in front of you when it’s mounted on a pistol make it parallax free?


    • Half,

      They (REFLEX) should mostly all work on pistols as well as most rifles with a long enough rail to provide the minimum eyerelief. I think B.B. had not much room to hang that reflex sight other than on the very back of the IZH 61 receiver.

      Even though the advertisement says unlimited there usually is a closest distance limitation on the REFLEX sights on the tube model Red Dot it is usually bad inside of about an inch. The specs should give that minimum or be available on the companies website.


      • Shootski,

        So I guess I understood what was going on with BB’s sight. Dot sights ARE pretty much parallax free provided they are not used too close to the eye, but he had no choice with the rifle he was trying to mount it to. Is it true whether it be a tube, a reflex or a holographic sight. All I’ve ever used are the cheap ones that Daisy and others sell that involve bouncing a (too large) LED off of a one-way mirror. Don’t really even know what that’s called.

        Another thing that I’ve been curious about is how the diameter of the dot is described. It seems to me that if the sight is closer to the eye the dot would appear bigger (cover a larger piece of whatever it’s being aimed at) and the opposite would hold true if your eye was further back from the sight. If i’m thinking right on this (and if I’m not, I invite some help so I CAN understand properly) that means that the anatomy of the tester would play a part in rating a dot as 2 MOA or 4 MOA. A Heavyweight boxer using it on his handgun would experience the sight quite differently than say, a Jockey shooting the same gun. Is there an industry standard eye distance for testing or am I just wrong in my thinking? Since one of the key features that drives cost on these sights seems to be the dot size, with smallest costing the most, a standard way of measuring the dot would be fairest to the consumer, but I wonder if there is a standard.


        • Half,

          B.B. will need to answer what he thinks the actual issue was. The entire discussion about, Red/Green/lots of colors, Dot system(s) is fraught (messed up) by loose language usage. The dot is a single plane presentation so the dot and target should never suffer from parallax but in fact they do!
          One thing to remember is there is a lens involved, even if it has NO magnification, it still has light dispersion and reflection.
          MOA, (Minute Of Arc) is not anything more than angle. It happens to discribe about a 1″ circle (also called Hunter’s MOA) at 100 yards; actually it is 1.047 inches at 100 yards (2.908 cm at 100 m) how we usually think of it in shooting. A SEARCH ENGINE will give you a real shock if you had never searched: minute of Arc.
          “It seems to me that if the sight is closer to the eye the dot would appear bigger (cover a larger piece of whatever it’s being aimed at) and the opposite would hold true if your eye was further back from the sight. If i’m thinking right on this (and if I’m not, I invite some help so I CAN understand properly) that means that the anatomy of the tester would play a part in rating a dot as 2 MOA or 4 MOA.”
          Nope, none of that comes into play! It is just an angular dimension (MATH, specifically Spherical Geometry) the 4MOA dot at 25 yards covers a 1.047 inch target, if you move the target to 50 yards you need a 2.094 inch target to cover it, and if you move the target to 75 yards you will need a 3.141 inch target for the same dot to cover it. I’ll do one more a longe range to hopefully make it perfectly(?) clear: at 300 yards that 4MOA dot covers 12.564 inches; gives pretty much a human center of mass kill shot!
          I hope that clears up most of it, keep asking questions and perhaps read the Wikipedia entry on Minute Of Arc.
          One last thing, look at B.B.’s blogon the ROMEO5 and look at the circle/2MOA dot illustration; no way that you can line up 32.5 of the center dot side by side ’cause that is not how it works!
          More questions???


          • Shootski,

            If what you say is true, how come I can see more around a chocolate chip cookie, if I hold it at arms length, than I can if I hold it along the side of my nose. At that point it is covering my entire world, wouldn’t you agree?


            • Half,

              Because Chocolate Chip Cookies (CCC) are real and have nothing to do with angles of Arc and Spherical Geometry!
              I very much like them, CCC, with a cup of Tips, 3 minute brewed, Tea these days! MOTLFOTH is what CCC are: Minute On The Lips Forever On The Lips.


                • RidgeRunner,

                  AMF Brunswick?
                  I like dents causing standing waves on rivers, inlet narrows when I’m in my kayak they are lots of fun. I also like standing waves in the air when I get to fly a soar plane (performance glider) for a long distance/duration flight. But, in my waveguides unintended perturbations are not welcomed!

                  As far as Hips (I hate SLOW and disobedient Spell Checkers)…yes in MOTLFOTH! But my black tea of choice is PG Tips http://www.pgtipsusa.com


                  • Speaking of AMF, it seems like Harley is taking another dive. The CEO just pulled the ripcord on his golden parachute. My bike might be worth something in a few years.

            • Half,

              Eat the cookie and look through the site.

              You guys have raised some very good questions that likely even the marketeers of these dot sights cannot answer. Here is my question. Does it really matter?

              There may actually be an industry standard for rating the diameter of a dot in a sight, but I doubt it. The claimed dot diameter is likely wrong, but is a good guide to whether it is big or little. You should remember that big is easier, both in dot size and increment movement, so they tend to be cheaper. Other factors are robustness. That adds to cost.

              Hey, they are all manmade. All have flaws.

  8. Half

    Eye astigmatism may cause the dot to enlarge or distort with some but not all dot sights. If you have this common eye condition I think you should look before you buy.


    • Decksniper,

      I have very good distance vision with some astigmatism in my non-dominant eye that requires me to wear glasses for the best possible distance vision with that eye and that caused a slightly different problem for me when I have used dot sights in the past. I can’t ever get my darn specks clean enough to not see the dot as a smudge. I have to take my bifocal-ed glasses off when I shoot with a dot sight if I want to see it as a round dot. I guess we each have our own cross to bear. LOL

      I’ve looked through dot sights with my bad eye and saw exactly what you were warning me about. Thanks for taking the time because you’re right, the dot bulges and doesn’t make for a very good sight picture, thereby making a dot sight less useful.


      • Half,

        Do you get Anti-reflective Coated lenses? They are expensive compared to non coated eyeglasses but for years they did the job for me when I Called The Ball, https://en.m.wikipedia.org/wiki/Optical_landing_system. on my approachs to the flightdeck. The coatings also work for shooting and help greatly with driving at night; unfortunately I am now to the point that my Cataracts need to be delt with so even the lens coatings on my eyeglasses are not doing the trick. I’ll be getting the eyes fixed this year first my nondominant which is the worst and then my shooting eye.


      • Half

        Peeps work better for me. Peeps that attach to glasses may make a blurry dot sight work too. But some dot sights are okay even for my eyes. You may find some you like.


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