by Tom Gaylord, a.k.a. B.B. Pelletier
Gamo P-25 is a 16-shot blowback pellet pistol.
Today, we’ll look at the velocity of the Gamo P-25 air pistol, and something interesting that happened. Normally, I report on the velocity of 3 or 4 pellets and leave it at that, but a strange thing happened with the first CO2 cartridge in the test pistol.
I didn’t screw the piercing screw deep enough into the CO2 cartridge, resulting in the gas flow being hindered. I’ve experienced this a few times in the past, but this time it was very pronounced. After each shot, there was a period of time that ranged from 5 to 10 seconds, during which the gas flowed audibly from the cartridge into the gun’s valve. It sounded like a leak in the gun, but I noticed it only lasted a few seconds before stopping, so it wasn’t venting to the outside. It was the gas flowing from the cartridge into the gun’s valve, where it would be used for the next shot.
The piercing screw wasn’t turned in far enough to properly pierce this cartridge. You can’t even see the opening through a 10X loupe, but it’s there. This was operator error.
Shooting the pistol in the rapid-fire mode proved impossible with this first cartridge. The first shot went out at the normal velocity, and shot 2…fired immediately after the first shot…clocked 88 f.p.s. through the chronograph.
It was my fault
So, I screwed the piercing screw much deeper into the next cartridge. Problem solved! Don’t be tentative when piercing a cartridge in this pistol. Do it like you mean it. After I pierced the second cartridge correctly, the pistol performed exactly as expected. Rapid-fire worked as you would expect, and the gun kept up with my trigger finger.
The first pellet I tested was the RWS Hobby. Weighing 7 grains, the all-lead Hobby pellet tells me so much about an airgun’s powerplant. For starters, it tells me what needs to be done to get the 425 f.p.s. velocity that’s claimed for the gun.
Hobbys averaged 353 f.p.s. in the P-25. They ranged from a low of 333 to a high of 379 f.p.s., and some of that large variance may be due to the gas flow problem I mentioned. At the average velocity, Hobbys were generating 1.94 foot-pounds of muzzle energy.
The Hobbys told me what I wanted to know. This pistol wasn’t going to get its rated velocity with a lead pellet. So, I needed to try it with a lead-free pellet; and since this is a Gamo gun, the Gamo Raptor PBA sounded like a good selection.
The Raptor PBA pellet is made from metal that’s harder than lead. It weighs 5.4 grains and will generally boost the velocity of an airgun above what a lead pellet will, though the hardness of the metal actually slows it down sometimes. But in the P-25, the Raptor PBAs worked just fine. They averaged 412 f.p.s. and ranged from a low of 395 to a high of 432 f.p.s. So, the ads are right on the money. At the average velocity, this pellet generates 2.04 foot-pounds of energy.
Next up were the lead Gamo Match wadcutters. They weigh 7.56 grains and are sometimes quite accurate in some guns. In the P-25, they averaged 348 f.p.s. with a spread from 329 to 357 f.p.s. The average energy was 2.03 foot-pounds. This will be a pellet to try in the accuracy test.
Crosman Premier 7.9-grain lites
The last pellet I tested was the 7.9-grain Crosman Premier lite. They fit in the circular clips of the magazine rather easily, which caused some concern they might fall out; but the way the magazine is designed, only 2 pellets at a time are exposed in its clip. So the worry was for nothing.
The way the magazine is designed, the pellets are not exposed until they’re ready to be shot. This one needs to be pressed into the clip.
Premiers averaged 344 f.p.s. in the P-25, with a spread from 330 to 360 f.p.s. At the average velocity, they generate 2.08 foot-pounds at the muzzle.
The double-action trigger-pull broke at exactly 8-1/2 lbs., which is light for a DA pull. On single-action, it broke under 4 lbs., with a huge creep at 2-1/2 lbs. That creep is consistent and lets you know when the gun is ready to fire.
While I got just 50 shots on the first cartridge, I got more with the second one. Besides the velocity testing, I did another test with an entire cartridge, just to see how the pistol operates in the rapid-fire mode. So, the correct piercing is very important. I fired an entire cartridge, just to see how the pistol handled. Everything worked smoothly until shot 48, when the blowback failed for the first time. After that, the blowback would work if I waited long enough between shots, but not if I shot rapidly. However, if you allow time for the gun to warm up, it keeps right on shooting.
There are certainly 75 or more powerful shots in the gun if you allow the gun to rest between shots. The blowback will work reliably past shot 50, as long as time is taken between shots. Shoot fast, however, and the gun cools too much and wastes gas.
Impressions so far
So far, I like the P-25. I like its simplicity and the light single-action trigger. If it’s also accurate, this might be a best buy.