The BAM B15 breakbarrel was so unknown to me that I had to figure out how to best test it.
This report covers:
- Thoughts
- Does it work?
- As you test
- Which pellets to try?
- Ten-shot groups
- What about…
- Powerplant
This report came about as the byproduct of recently testing the BAM B15 breakbarrel. If you recall that rifle wasn’t even working when I tried to shoot it, so it seemed as if everything had to be done. The question was—where to begin. When you don’t know what you don’t know, how can you test an airgun?
Thoughts
I have thought long and hard about this and have decided this makes an ideal topic to discuss because many of us face the same problems, and not just with older airguns. The Black Bunker BM8 survival air rifle is a perfect example of a brand new airgun that we knew next to nothing about. The manufacturer will tell us things, but until we test the rifle we know very little.
Vintage airguns like the B15 shown above are even harder because often not much is written about them. Where do you start?
Does it work?
An airgun has to work before it can be tested, so that was the starting point for the B15. The first thing I did was disassemble the rifle and overhaul it. That told me a few things, like the fact that everything was bone dry and the breech seal needed replacing.
There was a lot of discussion about the seal and I was told many things I should do, but you know what? I just made do the best I could and installed a new breech seal. And it worked.
I also discovered that the mainspring was weak so this wasn’t a powerful breakbarrel. When it came time to test I knew that lighter pellets would work best. I’m learning.
Once I had it firing pellets I discovered that seating them deep in the breech made them faster and more stable. That’s another data point.
Then I shot for accuracy. While it wasn’t that accurate with the three pellets I tried, one was clearly better than the others. Another data point.
As you test
As you test and try different things you refine your understanding of what’s being tested. For example I would not try slugs in the B15 because it wouldn’t shoot them fast enough for accuracy.
Try to establish how the gun wants to be held. This applies more to rifles. Can it rest directly on the sandbag or does it need the artillery hold? And some rifles need to be held tightly.
Which pellets to try?
I have said many times that I like to test with pellets I think give an airgun the best chance for accuracy. I test so many airguns that I don’t waste my time with anything but the best. That does make me subject to overlook a pellet that could be great in one certain airgun. That’s where you readers have the advantage.
Ten-shot groups
I made this comment in the B15 accuracy report, “This test of an air rifle was a doozie because I knew nothing about the airgun before starting it. The sights were way off the mark and, since I had no idea of what pellets the rifle liked, I had a hard time knowing whether the rifle was shooting where I wanted or if the shots were hitting the target just as a result of luck.”
This is the main reason ten-shot groups are better than 5-shot groups. You can put five in the same place by sheer luck. But in the 65 years I have been shooting I have only seen ten shots go into a tight group by chance once. You don’t need 15 or 20 shots. Ten will do.
What about…
The trigger? Observe it to see if it is getting smoother with use. How many stages are there and is the last one positive without any creep? Most importantly—is it safe?
The barrel lockup? If the barrel (of a breakbarrel) is wobbly in the action forks, try pushing it into one position just before shooting. If groups shrink, that’s something to work on.
The shot cycle? Try to analyze it for faults that can be corrected. For example, I mentioned that the B15’s ball detent that locks the barrel is rough. I said that’s a fault I don’t know how to correct and that makes the rifle less than desirable to me.
Accuracy? Quit worrying about the crown on the muzzle and concentrate on the size of the groups. If the gun is accurate who cares what the muzzle looks like?
Tightness of the stock screws? This can be a very important factor in accuracy. Be sure to check before shooting groups.
Powerplant
The things I’ve said today mostly relate to spring-piston airguns. Pneumatics and CO2 powerplants have some different issues that I think need to be addressed, but first I want to see your comments to this report.
The post Testing an airgun you know nothing about: Part One first appeared on Pyramyd AIR.
