by B.B. Pelletier

Photos and tests by Earl “Mac” McDonald

Part 1

The Benjamin 397C (right) is smaller than the 397 long gun.

We’re continuing our look at the Benjamin 397C that we started recently. It seems this model caught a lot of people off their guard, as the responses agree that not many people were aware it had even been made. In Part 1, I made reference to a comparison between this carbine and the 397 long gun, but I hope you understand that Mac is testing just this one gun. I’ll refer to the 397’s performance through the published specs and what I know of the gun. I invite any readers to add their comments as well.

Beautiful wood
Milan commented on the fine wood of the 397 rifle shown in Part 1, and I guess I should have said more than I did about it. Benjamin traditionally bought the wood for their rifle stocks from Stover, Missouri, and lucky owners often got beautiful stocks through the luck of the draw. The factory never made any attempt to segregate the wood by grain pattern.

I owned one Sheridan Silver Streak with a gorgeous crotch grain stock that would have added 50 percent to the price of any firearm it had been on. The wood on my current Blue Streak is pretty nice, too. So, good wood goes hand-in-hand with both the Benjamin and Sheridan names.

Velocity day
Today is velocity day, and it’s when we find out what has been sacrificed to shorten this carbine. Mac did several tests to help us understand how the multi-pump powerplant works. For starters, he pumped the gun different numbers of strokes and obtained the average velocity for each set between 2 pumps and 8. Let’s begin there.

The pump lever must be pulled down and forward like this for every pump.

All the following shooting was done with 7.9-grain Crosman Premier pellets in .177 caliber.

Pumps
Velocity
Low
High
Spread
2
325
318
331
13
3
407
401
412
11
4
466
462
471
9
5
511
509
513
4
6
544
538
549
11
7
576
573
582
9
8
596
593
598
5

We can learn some things from this data. First, notice that as the number of pumps increases, the velocity jumps get smaller. This demonstrates the diminishing returns that are common to all multi-pump pneumatics.

Another thing to take away from this is that the rifle is more stable at certain numbers of pumps than at others. Five pumps, for example, vary by only four feet per second across all ten shots, while six pumps vary by almost three times as much. What you can learn from this is that each rifle is very particular in how it behaves and you really need to know your rifle well. However, I’ll let you in on a little secret. In all the testing of both Benjamin and Sheridan multi-pumps that I’ve done over the years, I’ve found that five pumps is sort of a magic number for all guns. Fo some reason, they all seem to do well with five pump strokes.

And another thing. If Mac didn’t have a chronograph, none of this testing would be possible. Just one more useful thing you can do with them.

The last thing we can learn from this data is that a ninth pump stroke is probably not going to give any more velocity than eight strokes. In fact, it’s more than likely that the ninth stroke will actually make the rifle shoot slower than it does on eight. You can see that coming by looking at how close the average velocities are between seven strokes and eight. There’s an increase of only 20 f.p.s., while the difference between three and four pump strokes is 59 f.p.s.

What about nine pumps?
So, should you even try a ninth stroke? The answer depends on the gun. Most guns will not shoot any faster on nine pumps than they do on eight, but a few will. The gain might only be five f.p.s., but it will be a gain, nevertheless.

Most rifles will not increase, though, and after the shot when they’re cocked and fired again without pumping any additional times, you’ll hear some air exhaust. So, the ninth pump stroke was a waste of energy.

Bear in mind that the higher number pump strokes put a greater strain on the pump mechanism of the earlier ones because of the additional effort that’s needed. These guns have been designed to last virtually forever on eight pump strokes, but as you exceed that number the additional wear will cause them to wear out. When I was a kid, I used to hear adults brag about how they pumped their old Benjamin rifles up 30 times and they shot just as hard as a .22 rimfire. That’s hogwash! I can prove they won’t work that way, and if they really did pump their guns 30 times, which is next to impossible, they probably broke them.

Mac did pump his gun nine times for this test and he found that the velocity did go down by a few f.p.s. He didn’t keep a record of how much it dropped, so I can’t tell you that, but the rifle did exhaust air when it was cocked and fired again without pumping it again.

Velocity test
For this test, Mac started all over again. He didn’t re-use the velocity from the first test. This test was done at 8 pumps for every shot.

This time, Crosman 7.9-grain Premiers averaged 595 f.p.s. and ranged from 593 to 598, for a spread of five f.p.s. At the average velocity, the muzzle energy is 6.22 foot-pounds.

RWS Hobby pellets averaged 631 f.p.s., ranging from 626 to 638 f.p.s. That’s a spread of 12 f.p.s. The average muzzle energy was 6.19 foot-pounds.

RWS Superdomes averaged 596 f.p.s., with a spread from 592 to 602 f.p.s. The average energy was 6.54 foot-pounds.

Well, that should settle the question of what happens when a pneumatic is shortened. The velocity drops as the barrel gets shorter. The longer 397 rifle would get between 725 f.p.s. and 775 f.p.s. with 7.9-grain Crosman Premier pellets; and at an average of 750 f.p.s., the energy would be 9.87 foot-pounds. That gives you a good comparison between the long gun and the carbine.

Some readers have commented that the Benjamin 397 is already a smallish air rifle and wondered if it is really necessary to make a carbine out of it? I guess that’s a good question, because the longer gun has been in production for almost two full decades while the carbine lasted only four years. But Mac insists this is a very handy airgun, so I guess it’s one of those personal taste choices. If you look at the photo at the top of this report, you’ll note that even the pull length has been scaled back by an inch, so the carbine is undoubtedly best suited to shooters who either want or don’t mind a short-pull rifle.