Air Venturi Seneca Eagle Claw lever action repeater: Part 5

Eagle Claw lever action repeater.

Part 1
Part 2
Part 3
Part 4

This report covers:

• Filled to 200 bar
• The test
• The numbers
• String two
• Discussion 1
• Discussion 2
• Discussion 3
• Summary

Today I do a special test and report on the Seneca Eagle Claw lever action for a reader. 1stBlue, named Rob, asked me the following.

“BB,

Good morning sir, I am curious to know if you might consider shooting a string with a slightly higher starting velocity from a fresh 2 bar fill, to see if the jump in velocity that occurs with this technique can be flattened out a bit? So start at 4 clicks on the power wheel, and use the same method. It works well.

Rob”

This was my answer.

“Rob,

I will do it for you, but I think it won’t flatten that much.

BB”

I said that because of my previous experiences with Korean precharged pneumatics (PCPs). They are generally set up for all or nothing. However, in the interest of exploring the possibilities, let’s now see what Rob’s suggestion gives us.

Filled to 200 bar

I filled the rifle to 200 bar and then set the power wheel 4 clicks up from the bottom. Since there are 7 clicks on the power wheel, this is exactly in the middle.

The test

I shot the same H&N Baracuda Match pellets that I used in the tests in Parts 2, 3 and 4, just to keep things the same for today’s comparison. The first string averaged 958 f.p.s. with a spread of 13 f.p.s. from 951 to 964 f.p.s. The standard deviation was 4.58 f.p.s. And I need to tell you something about these numbers.

When I report the velocities I always round off the numbers. The chronograph gives decimal fractions and I round off. I use the standard convention of rounding up if the number to the right of the decimal is five or more and down if it’s 4 or less. That makes the velocity numbers cleaner in my opinion, and we all know there is some slight error in the numbers, due to small inaccuracies in the chronograph. Therefore I report the average as a whole number, too, even though the chronograph might say that it’s a decimal fraction. But the standard deviation is a number generated by a complex formula, so I am reporting that exactly as it appeared on the chronograph. That’s why it will usually be a decimal fraction.

String two

Shooting at the same power setting of 4 clicks up from the bottom, the second string of 10 Baracuda Match pellets averaged 964 f.p.s. The extreme spread for this string was 19 f.p.s. and the standard deviation was 7.07 f.p.s. The low velocity was 955 f.p.s. and the high was 974 f.p.s.

Discussion 1

String two shows us several things. First, the average velocity is 6 f.p.s. faster than string one. That tells us that at 4 clicks up from the bottom, the 200 bar fill was just a bit too much pressure to start with and when the pressure dropped by about 20 bar, this power setting became optimum (i.e. max power). The high for this string was 974 f.p.s., which is the fastest shot we have recorded with this pellet.

And there is more to see if you look at the string, shot by shot. Let’s do that. I will number the shots from the initial fill.

Shot………..Vel.
11………….955
12………….966
13………….967
14………….974
15………….974
16………….966
17………….961
18………….961
19………….956
20………….955

Looking at this string I can see something that I have seen with other Korean hunting airguns. Shots 14 and 15 are the peak shots. The velocity starts dropping linearly after those two shots. The Eagle Claw is falling off the power curve for this power setting and pressure in the reservoir. To demonstrate that more clearly, I shot a third string and got the following results. There was 160 bar air pressure in the reservoir at the start of this string.

Shot………..Vel.
21………….950
22………….942
23………….933
24………….929
25………….921

It’s pretty obvious, right? The Eagle Claw can’t sustain its velocity at this power setting. So at this point I moved the power wheel up a notch, to 5 clicks up from the bottom. And then I shot the remaining 5 shots.

Shot………..Vel.
26………….949
27………….945
28………….937
29………….932
30………….932

At the end of this string of 10 shots there was 140 bar of pressure remaining in the reservoir. Since the power was dropping I adjusted it up to 6 clicks up from the bottom. Remember — there are only 7 power adjustments on the power wheel of this rifle, so we are almost at the top.

Shot………..Vel.
31………….927
32………….926
33………….919
34………….915
35………….907

Okay — time to go all the way to the top.

Shot………..Vel.
36………….902
37………….896
38………….889
39………….882
40………….874

Discussion 2

Is anyone not aware that we have reached the end of the useful air charge? So, Rob, these are the results I got when starting with a fresh fill and with the power setting 4 up from the bottom. 

Now let’s compare today’s results to what we saw in Part 4, where I started with 3 clicks up.

Starting with 3 clicks up from the bottom netted an average 927 f.p.s. on the first string of ten shots. String two in that test did the same thing as strings 2 and three in today’s test. It started high at 934 f.p.s. but on shot 5 (for the second string, which is shot 15 on the fill) it started dropping linearly and ended at 897 f.p.s. I think the power wheel should have been adjusted up to 4 clicks up from the bottom for the entire second string.

I did adjust the power up to 4 clicks from the bottom on the third string. And the rifle registered 964 f.p.s. on the first shot of the third string, which was shot 21 from the fill. By the end of that string, the velocity with this same Baracuda Match pellet registered 944 f.p.s. For the record that is a string of 33 shots, where the highest velocity with the Baracuda Match pellet was 965 f.p.s and the lowest velocity was 897 f.p.s.

I was then able to adjust the power to 5 clicks from the bottom and got a string (shots 31 to 40) that was 954 at the top and 908 at the bottom.

Discussion 3

What I think has to be done is to be willing to accept a total velocity swing of about 40-50 f.p.s. for the fill and begin shooting at 3 clicks up from the bottom. Shoot the entire first string on that setting. Then shoot the next 5 (shots 11 to 15) on 3 clicks up and then adjust up to 4 clicks for the remaining 5 shots. For the third string (shots 21 to 30) adjust 5 clicks up from the bottom at the start and in the middle of that string, adjust the power up all the way.

Summary

I believe that the Eagle Claw gets about 30 good powerful shots on a fill, when the power wheel is adjusted carefully. You have to be willing to accept my 40-50 f.p.s. spread over those 30 shots. Thanks to Rob’s question and today’s test I believe that has been resolved.

This is as far as I will take the velocity test. I now want to test accuracy, because several readers are waiting to see what the Eagle Claw will do. If it’s like other Korean hunting air rifles the accuracy should be pretty good.

Tom Gaylord (B.B. Pelletier)

Tom Gaylord, also known as B.B. Pelletier, provides expert insights to airgunners all over the world on behalf of Pyramyd AIR. He has earned the title The Godfather of Airguns™ for his contributions to the industry, spending many years with AirForce Airguns and starting magazines dedicated to the sport such as Airgun Illustrated.

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