Crosman 2100B multi-pump air rifle: Part 2
by B.B. Pelletier
Today, we’ll look at the velocity of the Crosman 2100B multi-pump, and a strange thing occurred during the test. Actually it was two strange things — one an amazing coincidence and the other just weird. Both relate to oiling the gun, and both will be informative.
First, the coincidence. As I was writing this blog (last week, because I’m in Las Vegas at the SHOT Show this week), I got a question from a reader whose 2100 wasn’t pumping air. I asked him if he had oiled the pump piston head like he was supposed to, and I directed him to the online owner’s manual that tells how to do it and to a blog I wrote years ago that tells the same thing. A couple hours later, I get a thank you message that he’s oiled the gun and it seems to be holding air.
So, there I am in my office pumping the gun and shooting it for velocity and I ask myself about the state of the pump piston head of the particular gun I’m testing. Sure, it’s brand-new, but that doesn’t mean that it has enough oil. I look, and the pump head appears to be dry. For those who wonder what I’m talking about, please read the manual.
Then, I recalled that someone had guessed that this rifle would shoot in the low 600s with lead pellets, because someone he knew had tested it. Lo and behold, it was shooting only about 622 f.p.s. on 10 pumps (which is the maximum) with Crosman Premier 7.9-grain pellets. Wow! He was right!
But, wait! The pump head was dry, so I oiled it with some Gamo oil for CO2 guns. The velocity jumped to 658 f.p.s. with the same pellets and 10 pumps. But after about 10 shots the velocity started declining again.
So, I oiled the pump head again — this time with Crosman Pellgunoil. The velocity jumped to 690 f.p.s. before sliding backward to the 620s.
What did I learn?
First, I re-learned for the umpteenth time how important it is to oil a multi-pump gun. That was all it took to fix the reader’s rifle! Second, I saw that the test 2100 rifle responds to oiling immediately, but falls off again almost as fast.
So, the published velocity of 725 f.p.s. can probably be achieved with real-world lead pellets for a brief time, but this test gun won’t hold that velocity very long. Maybe the material the pump head is made of needs a break-in period? I don’t know. What I do know is that I can change the velocity of this gun by 70 f.p.s. simply by oiling it.
It doesn’t end there, however. While that story was unfolding I was also experimenting with the speed of my pump strokes. Since the pump head seemed somewhat hard, I figured that faster pump strokes would build more pressure. And they did! I could increase the velocity by 10 f.p.s. at least, just by changing the speed at which I pumped. I’ve tried the same thing in the past with other multi-pumps, but this one is particularly sensitive.
I think the most representative method of testing this rifle for velocity is to let it sink back to its lowest velocity and stabilize there. That way, the velocity test will also represent the velocity at which the accuracy test is conducted, because I’m certainly not going to oil the pump head after each and every group! Undoubtedly, there’s sufficient oil in the gun right now because of the two oilings I mentioned.
The first pellet tested was the 7.9-grain Crosman Premier. Since the 2100 is a multi-pump, I decided to test each pellet and BB at 5 pumps and 10. That gives us a good picture of what the gun can do across the entire range.
On 5 pumps, Premier lites averaged 540 f.p.s. when the gun was pumped fast. They ranged from 537 to 543; and at that velocity, they produced 5.12 foot-pounds On 10 pumps, again with rapid pump strokes, this pellet averaged 630 f.p.s. The range went from 628 to 635 f.p.s., and the average muzzle velocity was 6.96 foot-pounds.
JSB Exact 8.4-grain dome
Next I tried the 8.4-grain JSB Exact dome. On 5 fast pumps they averaged 526 f.p.s., with a spread from 517 to 531 f.p.s. The muzzle energy averaged 5.16 foot-pounds. On 10 pumps, they averaged 608 f.p.s. with a spread from 595 to 611 f.p.s. The average muzzle energy was 6.9 foot-pounds.
JSB Exact RS
For a light pellet, I tested the JSB Exact RS. The name of this pellet includes the word Match, but they’re domes, not wadcutters, and cannot be used in formal match shooting. At 7.33 grains, they’re very light, yet I’ve had some good luck with them in other pellet rifles.
In the 2100, 5 pumps gave an average 559 f.p.s. The spread went from 555 to 563 f.p.s. The average energy was 5.09 foot-pounds. On 10 pumps, the average velocity was 646 f.p.s., and the range went from 635 to 654 f.p.s. At the average velocity, the muzzle energy was 6.79 foot-pounds.
So, the reader who said the 2100 wouldn’t get to 700 f.p.s. was right. As long as you don’t shoot it immediately after oiling with Pellgnoil, it won’t shoot that fast. But oil it, and it’ll probably top 700 f.p.s. with lighter pellets.
On to BBs
BBs were next, and with them things are much more standard. Though there are subtle differences in BB brands, they don’t vary as much as pellets. We’ll now see if the advertised velocity of 755 f.p.s is reasonable. Since this is a Crosman gun, I tested it with Crosman Copperhead BBs.
BBs are loaded into the large reservoir, then the gun is shaken and they fall into the smaller spring-loaded magazine. Once the magazine is empty, you can shoot pellets again, even though there BBs are still in the big reservoir; if they aren’t in the magazine, they won’t load automatically.
On 5 pumps, Copperheads averaged 570 f.p.s. They ranged from 564 to 578 f.p.s. At the average velocity, they generated 3.68 foot-pounds of energy at the muzzle. On 10 pumps, they averaged 678 f.p.s. and ranged from 672 to 682 f.p.s. That’s an average muzzle energy of 5.21 foot-pounds.
So the bottom line is that the test gun doesn’t meet its advertised spec for velocity. It falls at least 73 f.p.s. short. It does the same with lead pellets, so I’m withdrawing my remark that the gun is suitable for light hunting. Clearly, it’s below the safe margin. Yes, it will kill small animals, but I could not recommend it for that task based on these results.
I also note that the barrel is starting to loosen at the breech. It rotates slightly at this point, and I’ll keep an eye on it. And the pump lever hits the gun with a loud slap on every pump stroke — there’s no cushioning material to deaden the sound.
I hope these results don’t disturb owners of this gun, because they in no way condemn it. The accuracy test is still to come, and we might get a big surprise there.
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