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.

Parallax!

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.

Build a Custom Airgun

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.

Velocity

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!

Trigger

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.

Shot…….Vel.
66……….351
67……….345
68……….337
69……….332
70……….324
71……….317
72……….308
73……….295
74……….279

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.

Summary

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!