Crosman 100 multi-pump pneumatic: Part 2
by Tom Gaylord
Writing as B.B. Pelletier
Crosman’s 100 is a .177 caliber variation of the more plentiful model 101.
This report covers:
- How much was it?
- How I know it holds
- The tests
- Test 1 — Crosman Premier lights
- Test 2
- Sig Match Ballistic Alloy pellet
- H&N Baracuda Match
- Trigger pull
- Power adjustability
- Loading is hard
How much was it?
Before I jump into today’s report, which is on the velocity of the Crosman 100, I want to make a comment on the price. I paid $150 for this one. It has just been refinished and the powerplant was overhauled — I think. Even if it wasn’t overhauled, it holds air for months (I’ll explain how I know that), so it’s the same thing.
Remember how rare I said these are? I see one for every hundred 101s (the .22 caliber version) at airgun shows. A nice 101 will run about $125-150, so I don’t think it’s too much to pay for the far rarer .177 version. Sure you will stumble into fantastic deals from time to time, but on any given day at a good airgun show, this is about what one of these will cost. They cost that much in the late 1990s, so the price isn’t being driven by inflation.
How I know it holds
Remember the picture I showed you in Part 1 of the cocking knob being unscrewed? If not, here it is again.
When the rifle is stored it gets two pumps of air and the cocking knob is unscrewed.
By unscrewing the cocking knob there is no pressure on the firing valve. If it is sealed well it should hold a long time. I’ve had multi-pumps hold air for more than a year.
Jeff Cloud told me the rifle had held air from the 2017 Texas Airgun Show (August 26) until he delivered it to me in early December. Now, I pumped it and shot it a couple times when I wrote the December 11 report on December 10. Today is December 21 and I screwed the knob back in and cocked the gun. Then I fired and it was still holding. That is my test for knowing if a multi-pump holds a charge.
Because the 100 is a multi-pump I’m going to test it a little differently than usual. I will talk you though my procedure in each section. I also plan to “larn ya” some things that a multi-pump lends itself to.
Test 1 — Crosman Premier lights
The first test will be conducted with Crosman Premier light pellets. I will test the rifle for velocity with 3 through 8 pumps, shooting 5 shots at each step and averaging them. I will give you the total spread and muzzle energy for each, as well
Pumps……Vel. avg…Total spread…..Energy ft. lb.
6……………566…………10……………5.62 no air left
7……………591…………07……………6.13 no air left
8……………605…………06……………6.42 no air left
Let’s talk. First off I have to tell you that this rifle is quite difficult to cock. The knob doesn’t give a lot of purchase and I had to use two hands most of the time. Next I want to say the rifle is performing admirably. There was no air left outside the reservoir until the 8th pump stroke. At that point the pump lever would jump back open, indicating that there was a little compressed air that didn’t go into the reservoir and remained ahead of the pump head.
After 6, 7 and 8 pump strokes I cocked and fired the rifle again, and there was no air remaining in the valve. This is as good as a multi-pump tune ever gets.
Notice the law of diminishing returns starts after 5 pump strokes. You are doing a lot of work for less and less velocity increase. This shows what some airgunners have a hard time grasping — that higher pressure doesn’t always mean more velocity. If I were to continue pumping we would reach a point where the velocity stopped going up and started back down again. That’s valve lock. Air would remain in the gun for a second shot. I won’t do it with this rare old gun but I have done it with my Blue Streak back in the days when Crosman still made them. As I recall, it happened around 10 or 11 pump strokes.
One last thing to note is how the rifle performed on 3 pumps, compared to 4. Notice that the velocity spread drops from 19 f.p.s. to just 6 f.p.s. with just one more pump. That is because the valve is operating efficiently on 4 pumps but not as much on just 3. This is for you TalonSS owners who wonder why your rifles get squirrely when you dial the power adjuster as low as it will go. It’s the same thing as 3 pumps versus 4. The valve just isn’t as efficient at the lower pressure, or in the Talon SS case, with a lower striker impact.
In this test we will see how a pneumatic powerplant performs. This will apply to all pneumatics, regardless of how the air gets inside.
You have read where a pneumatic and a gas gun (CO2) get more power with heavier projectiles. Let’s see that in action. We already know how much power a medium weight pellet generates on 8 pumps. What will a lightweight do? And how about a heavyweight?
Sig Match Ballistic Alloy pellet
The first test will be with the Sig Match Ballistic Alloy pellet. I will just do this once, now that we know how stable the rifle becomes with many pumps in it.
On 8 pumps the 5.2-grain Sig Match Ballistic Alloy pellet goes 712 f.p.s. At that velocity it generates 5.85 foot pounds of energy.
H&N Baracuda Match
Now let’s check a heavyweight. The H&N Baracuda Match weighs 10.65 grains and on 8 pumps the Crosman 100 spits it out at 540 f.p.s. At that speed the pellet generates 6.9 foot pounds.
So we have just seen an increase of a foot-pound of energy by moving from a lightweight pellet (5.85 foot pounds) through a medium weight pellet (6.42 foot pounds) to a heavyweight pellet (6.9 foot pounds). The same thing happens in all pneumatics, and the more powerful ones have a greater spread.
The trigger pull on this rifle is extremely variable — from it won’t stay cocked to 1 lb. 10 oz. That’s too light for a direct sear gun that’s this old. I think some parts are worn and need replacing.
As far as I know this rifle was never meant to have adjustable power, but that threaded cocking knob can make it happen. I unscrewed the knob 3 full turns and Premier lights dropped to 553 f.p.s. on 8 pumps. But since this is a multi-pump, why would you do something like that? Just pump it 5 or 6 times and get the same result.
Loading is hard
The 100 and 101 both have very little room for loading. The 100 is worse because it also has a smaller breech that’s hard to find. Wadcutters are especially hard to load. This might be the reason I got rid of my first one.
So far, so good. I find the Crosman 100 to be a fun gun to shoot, but the hard loading and cocking is a drawback. I like my 101 much better.
We will look at accuracy next.
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