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Ammo S&W 78G and 79G – Part 2

S&W 78G and 79G – Part 2

by B.B. Pelletier

Part 1

Today, we’ll look at velocity and power of the S&W 78G. I’m getting reacquainted with this pistol because I’d completely forgotten how it performs. For starters, I’d sent this gun to Dave Gunter in Oregon to reseal and soup it up. Dave and I decided that I wanted the maximum power I could get from the gun, so that’s what he gave me.

Dave also told me I’d get only a few shots from a CO2 cartridge at this power level. I accepted that because I seldom shoot CO2 guns, anyway, so gas conservation isn’t high on my list, but in this case performance was.

In Part 1, I neglected to tell you about the pistol’s other modifications. At some time in the past, the former owner had the trigger turned into an adjustable one. Though it’s only a single-stage regardless of where the trigger is set, the let-off can be adjusted down into the dangerous range. It was set that way when I bought it through the internet, and I asked Dave to adjust it to a safe level as long as he was working on the gun.

Trigger adjustment
He was shocked at how unsafe this kind of adjustment is, because all it does is reduce the contact area of the sear. For those who are new to shooting, the sear is that part of the trigger that safely holds the action in the cocked position until the shooter intentionally fires the gun through the use of the trigger. That last thing you want is a gun whose sear contact area is so small that it can slip off on its own or even slip when the gun is bumped slightly!

The trigger adjustment just changes the area of sear contact. This is not where the factory adjustment would be. And, yes, that is the first owner’s name scratched into the triggerguard. It’s also on the box.

Power boost
To get the power from the gun, Dave worked on the valve, both opening and smoothing the ports through which the gas must flow. he also switched the valve return spring to one better balanced to the modifications he’s made. That we cannot see because it’s buried deep inside the gun. But we can see one additional touch he added to the bolt. He thinned the bolt nose and smoothed it to reduce any resistance to gas flow.

The thinned bolt probe is seen on the left, and this photo shows you how the bolt opens straight back. Since it doesn’t cock the mainspring, the bolt is light and easy to move.

Velocity with RWS Hobbys
Okay, time to stop talking and start showing the performance. RWS Hobby pellets are lightweight .22 caliber pellets. At 11.9 grains, they’re just about the lightest all-lead pellets you can find. In my hot-rodded 78G, they average 532 f.p.s. with a spread from 523 to 542. That’s quite a bit faster than the 2240, so I remembered wrong. The average muzzle energy is 7.48 foot-pounds, or a full foot-pound more than the 2240. The 2240 averaged 482 f.p.s., and the Mark I averaged 472 f.p.s.. The 78G is clearly in the lead.

Velocity with RWS Superdomes
With RWS Superdomes the 78G averaged 492 f.p.s. The spread was a tight one, from 484 to 497 f.p.s. The average muzzle energy was 7.8 foot-pounds, so a little more than the Hobbys. For comparison, the 2240 averaged 455 f.p.s. (the Crosman Mark I wasn’t tested with Superdomes).

Velocity with Crosman Premiers
The 78G shot Crosman Premier pellets at an average velocity of 494 f.p.s. The spread went from 486 to 498 f.p.s. That works out to an average muzzle energy of 7.75 foot-pounds. The 2240 averaged 448 f.p.s., and the Crosman Mark I averaged 431 f.p.s.

So, what’s the downside?
You want that kind of power? Then you must pay. You might get that power from a longer barrel, but to get it from the stock 78G barrel means the total number of shots is just 15. There are powerful shots left after No. 15, and a casual shooter might see as many as 25 shots from one cartridge. For tight velocity spreads, 15 shots is all you get.

This is where the 2240 will kick the 78G’s butt. Because for only a few dollars, you can put on a longer barrel that will probably give you the extra oomph you want without disturbing the shot count. This is where the physics of CO2 operations comes into play.

But this 78G is still a cool air pistol. I’m having fun shooting it again after so many months of being dormant. It’s sleek and it’s powerful. We’ll find out next time if it’s also accurate.

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.

54 thoughts on “S&W 78G and 79G – Part 2”

    • rikib,

      A standard 78G shoots a medium-weight pellet at around 395 f.p.s. on high power, so it’s somewhat slower than the Mark I or 2240. I got that number for some testing I did of my other 78G years ago, however, I cannot tell you whether that gun had its power dialed all the way up or not.

      Lacking that information I would have expected the 78G to turn in identical performance with the Mark I, since they are both so similar.


  1. Good morning B.B. and all,

    I just wanted to post an interesting observation I just made. Tonight, for whatever reason, I I started wondering what is the effect of setting the pellet vs merely pushing wiht the finger until it is flush or close to flush. Using my Diana Mod. 40 in .177 cal, and CP light and heavy pellets, I found out that setting the pellet into the breech a very small amount (less than a millimiter), decreased the velocity of the CP lights from 930-940 fps to 895-905) fps. I then introduced pellets somewhat carelessly (some being flush, some sticking out below the seal, some set a small distance into the breech). Velocity spread went from the regular 10-12 fps to 50 fps. Similar results with the Heavy CP pellets.

    Also, the HW77 factory sample that was for sale the other day was sold in less than 3 hours. Just as I expected. So, next time, I will just buy and ask questions later. Now I understand why they don’t let you use cell phones in gun stores…

  2. BB,

    Hardly a fair comparison using a hot-rodded gun against two non hot-rodded guns. I would also like to see a comparison to a standard 78G.

    I know you probably don’t have access to a standard 78G but maybe some one could loan you one or just do the velocity tests if they have a chronograph.

  3. B.B.,

    Finally! I must admit I was too embarrassed to ever ask the question, but at last I know exactly what “sear” is:
    “…the sear is that part of the trigger that safely holds the action in the cocked position until the shooter intentionally fires the gun through the use of the trigger.”

    I always knew that the sear was a part of the trigger mechanism, but never exactly what. I had googled the term, looked in Dictionary.com and Wikipedia and at all my airgun books. Nowhere did I find a really precise definition of this term until you now gave it to us. Now if only I could see some pictures of the sear in different trigger assemblies…

    Thanks again for yet another nugget of knowledge!


    • AlanL:
      Hi,the Weihrauch I am after getting is the HW99s.
      A break barrel springer like the HW50s.
      Price was the over riding thing you see and the 99s is about $200 odd new in the UK.
      I have read over 68 reviews of this rifle now and they all really rave about it.
      Not only good value but it’s turned out to be a very respectable all rounder.

      • DaveUK,

        That’s interesting. The HW99S is not sold by Pyramyd, nor does it appear among the product offerings on Weihrauch’s website. Must be a model made specially for the UK. Looks a lot like the HW30. It must have the Rekord trigger to have the ‘S’ designation at the end. Does it? Are you contemplating .177 or .22?


        • AlanL:
          Indeed it does have the Rekord trigger.Cool!
          To be fair I only learned that after BB and Kevin told me what the ‘S’ meant 🙂
          As for calibre.Well .22 has to be the one I reckon.
          Being in a rural area, small game hunting and pest control will be on the cards for this rifle.
          Now depending on UK dealers, the price varies wildly for the 99s.Up to a about £60 difference in one case.Unbelievable.
          A dealer I found online has opened a branch near Boston close to me.He also happened to be the cheapest for the HW99s.RESULT 🙂
          Now the hard part.Wonga(money)lol

            • AlanL,

              They are similar Weihrauch guns.

              The HW50 is more powerful than a HW30. In .177 the HW50 specs at 820fps and the HW30 is 675fps. These numbers are from the Pyramyd AIR site.

              The HW50 I had and the HW50 my shooting buddy Erik just bought are very buzzy/twangy but are accurate. I sold mine. Erik is considering getting his tuned.

              A footnote on the Pyramyd AIR website: The R7 specs are 700fps in .177. Seems PA is souping up the R7 but leaving the HW30 alone LOL!


              • Kevin,

                The reason these two guns have different velocities is quite simple: HW quotes one velocity and Beeman has always quoted another. Of course, one is not anymore powerful than the other. What matters is which weight pellet was used for the testing. So, way back in time, HW tested with a certain pellet and got their velocity. Beeman tested with a lighter pellet and got another velocity. Voila! Same gun, different velocities.


  4. FrankB – I’m seriously jealous of your new rifle. I saw Derricks blog on it las night.

    Also, I saw on the vintage forum a pleasing quote pictured on an old Crosman box – “Power Without Powder” that kind of caught my fancy, they should bring it back.

    Lastly, I got my shipment from Maccari and re-assembled the RS-2. Even though the spring was 1 1/2″ longer than the original, it worked just fine. Cocked and fired without issue – well it issued the pellet, but there were no problems! I’m planning to shoot it a couple of hundred times and then start accuracy and velocity testing. I’ve found that working on the airguns is the most enjoyable part to me. It’s seriously rewarding to have taken a $45 piece of junk that was bedlinered of all things and completely tear it down and refinish/rebuild it into something that is a respectable air rifle. I can see what has driven the likes of Derrick to the heights he’s at now. Perhaps if anyone is interested, I’ll put some photos on photobucket this weekend.

    Next up the 34 Maccari kit installation…

  5. BB

    Doesn’t everybody scratch their name onto the metal of their guns with a screwdriver? I think I did a pretty good job on the TX200. I have to admit, I did misspell my last name the first time, so I had to cross it out and do it over.

    I hope that you are continuing to recover nicely.

  6. AlanL and other springer owners,

    You earlier asked to see pictures of the sear in different trigger assemblies. The rekord is one of the finest and very similar to most others.

    I like this interactive diagram of an R10 with rekord trigger. It explains a lot about how the typical breakbarrel functions. Once you’re at the diagram, look immediately below the gun and click on “sear engagement”. When that window opens, you’ll see a vertical rectangle that allows you to adjust the sear. At the bottom are active links as well that allow you to pull the trigger and reset the trigger. Just use your mouse.



    • Kevin, thank you for posting that link to Perry’s site. I have been there dozens of times and it never gets old looking at those demos and interactive pages! He did some great work on there.

      Should be required reading/viewing for all spring gun owners (and all airgunners generally).

    • Kevin,

      Thanks for the point to that website. That’s a great resource! I’m getting closer and closer to getting up the gumption to make or acquire a spring compressor and actually get inside one of my guns someday…


  7. So, I count two devices to prevent a sliding compression chamber in a spring gun from closing on your hand. One is the sear and the second is the anti-bear trap mechanism. I know one shouldn’t regard the sear as a safety device but it is protecting your fingers. I feel better although I keep my elbow in the way of the lever while cocking my rifle.

    My .22LR bullet trap arrived last night. Now, how do you suppose one transfers the load of seasoned duct seal from the old destroyed Crosman 850 trap to the new one? (I wish I could have taken a picture. The sides were all right but the steel plate at the back had been pushed several inches out and duct seal loaded with pellets was overflowing out of the trap.) I know the new trap can stop pellets, but I couldn’t have the sound of the pellets impacting metal in my apartment. I found out just how to transfer the old seal… I set the old trap on top of the new one sort of hoping the old seal would fall out at least with some assists from my hands. Nothing doing. The duct seal is sticky anyway and the force of impact had wedged it all in very tightly. Here began a lead-dust cloud filled disaster, and right when I had run out of my N-95 masks. In retrospect, my fixation on using the old duct seal did not make a lot of sense, especially since I had new bars handy. Maybe, the lead dust was affecting my brain. Anyway, I pulled and hauled at the duct seal. Around the sides of the trap, the blocks were more or less intact. But in the center, the pellets had churned it along with fragments of paper into a kind of brittle dust like a mummy. My hand broke through and bumps to the trap would deposit mounds of the stuff and showers of pellets on the rug. Walking through the house to dump the garbage and get more plastic bags tracked lead dust all over the place. My Shark indoor vacuum cleaner ran out of its battery charge before I finished. Argh. Slinging Lead, make sure to record this one. Anyway, I finally got the job done. So duct seal will not stand up to pellets forever, but it will for a very long time.

    BG_Farmer, glad you’re still out there. I’m still getting used to the new format myself. But I suspect the issue here is the increased volume of comments. Beyond a certain point, no format will compress this material into what we had before and a certain amount of Balkanization is inevitable.

    Duskwight, have fun in Portugal. On my trip there, the most amazing sight was not the historical places, nor yet the topless beaches (don’t try that one :-)). It was my aunt from Detroit Michigan who broke out mineral oil at the beach to magnify its rays on her skin when the temperature must have been about 100 degrees. I had a significant sunburn with sunblock, and she just got a tan though she’s quite fair-skinned. I have no explanation.


    • Matt,

      How do you exactly use duct seal in the pellet trap? do you entirely fill it with jumbled duct seal?

      If oyu are shooting around 950 fps+, you will likely still need it. My .22 cal trap safely and efficiently traps and contains .22 rimfire bullets.With pellets it is another story. They seem to splatter and break apart upon hitting the back plate and there is always a portion that bounces back. Large paper targets end up punched through from behind by countless little lead pieces. I bet that also depends on whether the pellet is pure lead or an alloy. I need an efficient and clean solution to this problem


  8. BB/Anyone (off topic):

    Does anyone know more about it than what’s on PA’s site or actually have the new Marlin Cowboy BB gun? I’m curious about the difference ‘twixt it and the Daisy Red Ryder (which I own). Specifically, it looks like it might load (under the bbl) the same way my ’50s RR did. Any other details/shooting impressions gratefully appreciated.


  9. JoeB,

    B.B. promised us a blog on the Marlin way back soon after it first was listed for sale, around the time of the posts about the Daisy Model 25. He blogged his initial impressions about it from last year’s SHOT show where B.B. saw a prototype or sample production unit. I can’t wait!


  10. I’ve met some really great guys because of airguns. Some of you may remember the airgun shoot I hosted at my place almost a year ago. 10-12 guys showed up and some have become good friends.

    One that couldn’t make it was Dr. Berger. First name Erik. Built like a viking. Works out at a gym everyday. His arms are as big as my thighs. Passionate about shooting anything. He’s from Georgia and was interviewing last fall with multiple hospitals. He’s a true southern gentleman. He had to leave for Georgia before my airgun get together.

    As fate would have it he chose to do his 3 year internship at our most prominent teaching hospital that’s only about 25 minutes from my home. He leased a house about 10 minutes from me. I’ve had him up to my cabin twice since he took his position this spring. Great guy.

    After his shift he showed up at my place this afternoon with his new Webley Alecto. He just got this gun and took it camping this past weekend. Killed several whistle pigs (marmots that in Colorado grow as big as large groundhogs) with his new Alecto pistol.

    I’m not a pistol guy but have to admit that this gun impressed me. It’s big. Reminds me a lot of the P17. It’s a Multi-pump pneumatic in .22 cal. Rated for 3 pumps but we put 4 in it a few times when shooting over the chrony. The adjustments on this pistol are amazing….palm shelf, grip, front and rear sights, trigger for pull, cant, LOP etc. Since he shot the marmots at 15 yards and had the sites adjusted for that distance that’s where I put the target. Gun hates hard ammo, i.e., crosman hollow points, crosman premiers in the cardboard box, etc. but loves pure lead. It really liked the jsb 14.3 (blue tin). One ragged hole with 5 shots. What also impressed me was the velocity spread. On 3 pumps this gun never varied more than 4fps when shooting the jsb’s!!

    B.B., Hope you get one of these soon from PA to test.


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