by Tom Gaylord
Writing as B.B. Pelletier

B3
The B3 underlever from China.

Part 1
Part 2
Part 3
Part 4
Part 5

A history of airguns

This report covers:

  • Pre-work baseline
  • RWS Hobby
  • Harsh firing cycle
  • Rifle is breaking in
  • Air Arms Falcon
  • Sig Match Ballistic Alloy
  • RWS Hobby again
  • Discussion
  • Cocking effort
  • Trigger pull
  • Summary

Today I will test the velocity of the B3 underlever that we cleaned and lubed on Friday. This will be a fantastic learning lesson for all airgunners, because the results are most informative!

Pre-work baseline

If you have been following this report you know I discovered in Part 2 that the rifle wasn’t performing to expectations. In Part 3 I replaced the breech seal and tested the velocity. That gave us a baseline we can use today for a before and after comparison. Let me get to the tests right now.

RWS Hobby

The first pellet to be tested was the RWS Hobby. In Part 3 Hobbys gave an average 617 f.p.s. with a 24 f.p.s. spread.

Now let’s look at how the lubed B3 did with Hobbys. Because of what happens in this string, I’m showing you every shot, and will then discuss it.

Shot………Vel.
1………….did not register (DNR)
2………….572
3………….604
4………….814 diesel
5………….822 diesel
6………….815 diesel
7………….805 diesel
8………….774 smoother
9………….743
10…..…….737
11…..…….734
12…..…….688 smooth!
13…..…….725
14…..…….705

Then, I had to take a short break and retire to my reading room. Let’s say I stopped shooting for 5 minutes.

15…..…….546
16…..…….565
17…..…….578
18…..…….567
19…..…….582
20…..…….689
21…..…….571
22…..…….699
23…..…….619
24…..…….557
25…..…….DNR
26…..…….570
27…..…….661
28…..…….DNR
29…..…….DNR
30…..…….576
31…..…….564

At this point I stopped shooting. Let’s look at these results and see what is happening. First, shot number 4 was a diesel — not a detonation. Dieseling is where the oil vapor is burning from the heat of compression and adding to the velocity, but there is no loud explosion like you hear with a detonation. Dieseling is normal and even good. Apparently this B3 is right on the cusp of dieseling, and, as I told you on Friday, I had saturated the leather piston seal with Crosman Pellgunoil. I could see oil droplets (in a fine mist) being expelled from the muzzle with every shot. That’s exactly what you want to see in an airgun that has a leather piston seal.

Harsh firing cycle

I told you Friday that the firing cycle became much smoother after the gun was lubricated. And the first three shots in this test were all very smooth. But the shots where I noted the dieseling were harsher than the others. They were almost as harsh as the shots from the time before the rifle was lubricated.

Notice that I said shot number 8 was smoother. I meant smoother than shots 4 through 7. The gun was still dieseling, but it was starting to settle down. Shot 12 was very smooth — about like what I saw in shots 2 and 3.

Rifle is breaking in

The reason I said today’s report is so special is that this string shows you what an airgun goes through as it breaks in. The B3 is a used gun, so what is breaking in and settling down is the oil on the piston seal. That’s why I wanted you to see the entire string — so you would appreciate what it looks like (and feels like) when a spring-piston air rifle breaks in.

If I were to look at this string and guess the final average velocity of this rifle with Hobby pellets, I would say 560 to 570 f.p.s. But — it ain’t over, yet! I decided that, because the rifle was settling down, I could now test the other pellets.

Air Arms Falcon

Next to be tested were Air Arms Falcon pellets. In the before test they averaged 605 f.p.s. with a 27 f.p.s. spread. I’m going to show you the entire string from this test, and then discuss it.

Shot………Vel.
1………….565
2………….564
3………….565
4………….562
5………….561
6………….566
7………….568
8………….559
9………….564
10…..…….561

This string tells me the rifle has settled down, and that’s why I showed it to you. The average for the string is 564 f.p.s. and the spread ranges from 559 to 568 f.p.s. — a mere 9 f.p.s. That would be good for an expensive spring rifle!

Sig Match Ballistic Alloy

Next I tried 10 Sig Match Ballistic Alloy pellets. Remember how very accurate they were at 10 meters? In the before test these same pellets averaged 688 f.p.s. with a 32 f.p.s. spread.

I won’t show the whole string this time, but the average velocity was now 628 f.p.s. and the spread went from 624 to 633 f.p.s. That’s another 9 f.p.s. spread! This rifle has definitely broken in with the lube I gave it.

RWS Hobby again

It was time to revisit the RWS Hobby, to see what the actual average was. Remember, after looking at the first string I guesstimated it would be in the 560 to 570 f.p.s. range.

The average this time was 541 f.p.s. The spread went from 534 to 547 f.p.s. — a range of 13 f.p.s. Well, the gun has definitely settled down and I was definitely estimating too high when I guessed based on the first string.

Discussion

Before the lubrication Hobbys averaged 617 f.p.s. with a 24 f.p.s. spread. After the lube Hobbys averaged 541 f.p.s. with a 13 f.p.s. spread. The rifle has lost 76 f.p.s. and the velocity spread has been cut almost in half.

Before the lubrication Falcons averaged 605 f.p.s. with a 27 f.p.s. spread. After the lube Falcons averaged 564 f.p.s. with a 9 f.p.s. spread. That’s a loss of 41 f.p.s. and a two-thirds reduction of the spread.

Before the lubrication Sig Match Ballistic Alloy pellets averaged 688 f.p.s. with a 32 f.p.s. spread. After the lube they averaged 628 f.p.s. with a 9 f.p.s. spread. That’s a loss of 60 f.p.s. and a reduction of the spread by more than two-thirds.

So the lube tune I did has cost me between 41 to 76 f.p.s. in a rifle that wasn’t very fast to begin with. I’m pretty sure that loss can be attributed to the use of Tune in a Tube grease on the mainspring, because I didn’t do much else. The oiling of the piston seal probably didn’t help or hurt the velocity, though it will prolong the life of the seal.

Cocking effort

The B3 took 32 lbs. of force to cock before the tune and it still takes that much. Before the tune I felt some spiking near the end of the cocking stroke and now that the action is lubed I can tell it is from the trigger parts being pushed out of the way by the piston. I can tell that because the rest of the cocking stroke is now much smoother.

Trigger pull

Before the lube the trigger broke cleanly at 5 lbs. 3 oz. After the lube it breaks exactly the same. Remember — I did not lube the trigger in any way, nor do I feel the need to. I know that sounds like a heavy trigger to many readers, but I grew up with military rifles and 5 lbs. is where they have always been. Even today a stock M4 or M16 is at that weight. So it seems normal to me. I also like lighter triggers like most shooters, and I really like crisp 2-stage triggers, but I am very satisfied with the trigger on this rifle.

Summary

I think today’s test was an important one for those who are trying to understand spring-piston air rifles. While a tune doesn’t change the accuracy potential of an airgun, I feel this B3 now shoots so well that I want to test it for accuracy again.