GSG 92 CO2 BB pistol: Part 2
by B.B. Pelletier
Today, I’ll report on the velocity of the new GSG 92 CO2 BB pistol. There wasn’t a lot of interest in this pistol, but one reader named Lee was very interested in it. He was comparing several seemingly similar pistols and stated that he was quite interested in the accuracy test. That’s in Part 3, Lee, but I’m also interested. I’ll never forget discovering what an accurate pistol the Umarex Makarov was, and then seeing Crystal Ackley shoot it on camera on the American Airgunner set as the first gun she every shot. We kept backing away from the target but her group never got any larger. Little did I know at the time that she was a natural shooter and would soon be out-shooting Paul Capello and me! Hopefully, this GSG pistol will provide a similar surprise.
How this pistol feeds
I said in the last report that I’d be showing you more of the interesting BB magazine in this report, so I’ll do that first. Because I don’t have video (and PLEASE don’t ask for it in the regular blog!) I’ll have to describe to you what happens when the slide blows back and returns to battery (to the point where it would be locked with the breech if this were– a firearm). In a normal BB gun, nothing happens when the slide returns to battery. The BB remains poised at the top of the magazine, waiting to be blown down the barrel by the blast of gas when the gun fires. Not so with this gun. This gun feeds each BB into the rear of the barrel.
In this photo the slide has returned part way and the round projection has just contacted the BB. It will now begin to push the BB out of the magazine lips and into a ramp that leads up to the rear of the barrel.
Here you see the ramp (the shiny part) the BB goes up to get into the barrel (just visible at the end of the ramp). Once the slide starts pushing it, it follows willingly up this ramp for a positive feed into the barrel.
What is described in the captions of the three photos above is the same feed method used by many semiautomatic pistols to feed cartridges into the breech of the barrel. It is much a more complex feeding process than most BB guns use, but only testing will demonstrate whether it is worth the effort.
Does it work?
The big question I had was if a complex feeding system like this would work reliably. Only testing can show that for sure, so some shooting was in order. And, the answer is that it works, but not every time. The gun was mostly reliable, but there were a couple times when the slide locked back as if the magazine were empty even though there were more BBs ready to go. One function of this pistol is it holds the slide open after the last shot, just like a firearm, but this one was doing it sporadically when there were still BBs in the magazine.
I will watch this trait as the test progresses. It may be that the gun suffers when held with a limp wrist, which is not uncommon with many firearms, as well. It’s possible to make many semiautomatic pistols malfunction by nothing more than holding them with a limp wrist that moves more than expected during recoil.
Using Daisy Premium Grade zinc-plated BBs, the gun averaged 332 f.p.s. The range went from a high of 350 f.p.s to a low of 319 f.p.s., and the velocity decline was linear from the first shot to the last. That means the gun is either cooling very rapidly, despite being tested in 75 degrees F temperature, or it’s running out of gas quickly. A second magazine would tell the story.
And tell the story it did. This time I was more positive about the hold and there were zero failures to fire. Then I limp-wristed a couple shots and behold — no more faulty hold-open events. Apparently, that was just a part of the early break-in.
On the second string of shots I allowed at least 10 seconds between each shot so the gun could warm up, and the velocity averaged 336 f.p.s. This time the velocity also descended for the first shot to the last, but the slope was shallower. The high velocity was 345 f.p.s. and the low was 327 f.p.s. Shoot the gun slower if you want more shots per cartridge.
Remember, this is a blowback pistol and some of the gas is being used to power the movement of the slide. That has to detract from the total number of available shots. The third string of ten shots began at 338 f.p.s. and ended at 316 f.p.s. Unlike many other gas guns, this one is getting progressivly slower as it shoots. That’s probably due to the blowback function that needs about the same amount of gas every time it cycles.
I shot a fourth string after waiting 24 hours. I wanted to see if there were ten more good shots remaining on the cartridge. I actually miscounted and loaded 11 BBs. The first shots was 330 f.p.s., so the gun was still on the charge, but by the fourth shot the velocity had dropped off to just 313 f.p.s. That was a clear sign that the liquid CO2 was gone and the gun was starting to drop in gas pressure with every shot. Shot 8 was 265 f.p.s. and shot 11 was 245. The gun is obviously out of gas at this point. That means there are about two full 20-shot magazines per CO2 cartridge. The slide was still cycling on the last shot, but it was going much slower than normal. Any more shots would be risking a jam.
From a realism standpoint, the GSG 92 is about as realistic as they get. The heavy metal slide imparts a good amount of recoil when it blows back, and that’s what a lot of owners will want from this gun. We’ll look at accuracy next. If this pistol is accurate, it’ll be one of the top contenders in the action BB gun class.