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.
Tom,
So research first to at least get an idea what it is and if possible how it should perform. Preliminary test for function. Determine areas that require repair to make it fully functional. Test for function again after repair, tighten all screws and then test for accuracy. If not accurate determine if there are factors that can be corrected to increase accuracy. If after all corrections accuracy is not at the desired level chalk it up as a learning experience and move on to the next project.
Is this a sufficient summary?
Siraniko
Siraniko,
Wow! That was an excellent summary!
In the words of a 19th century British seaman—I am impressed!
BB
That was a good pun-ishing shot accross the bow, Tom.
B.B.
What about “warm up shots”? Some need them, some don’t. How do you tell the difference?
-Y
Yogi,
That is a great question. Not that I know from testing, but experience tells me airguns need warm up shots more often than not. So warming them all up is a safe way to go.
BB
Yogi,
A very good question. My experience is similar to BB’s – most of them need 10 – 20 shots to get the system on the stable level for testing. I never start the accuracy test directly. Almost all springers I have need it (including FBW300s – I still don’t understand actually why 300s needs 10 shots to stabilize?). The PCP or CO2 powerplants seems to not really bother. After longer time not used (happens not so often) the FWB800 needs 2-3 shots to get it right. I think it is just pure mechanics of the valve. It happens only after a long time, I mean two weeks or longer.
All my CO2 powerplants are directly there. Stronger PCP’s seems to also be resistant against long sleeping time.
How to tell the difference? Testing, of course. If a breakbarrel sits for a spell, one could take Vana2’s test target and start shooting one shot per bull. After several shots, one can tell if the shots are settling into a group or not. I have seen some guns shoot a first shot to point of aim, 2nd shot high and right, and the next several shots “walking back” to the first shot, and then the rest of the shooting session will group back at the original point of aim. When you see this stuff repeatedly with the same gun, you’ll know how many warm up shots that gun needs.
BB,
This article is fantastic. Many should read it and take it to heart.
As is known here, I mostly deal with the “old gals”. What many do not realize is when they show up here, many do not work properly. Some of them do not work at all. Quite often I have to take them apart and figure out why they do not work. I have been fortunate that through much searching, I have found several folks who will source parts for some of these “old gals”. Unfortunately, some of those sources are drying up. Another problem is many of those sources are getting old like me. Also, finding some of these “old gals” and then deciding if they should be fixed up or taken apart for parts can be quite challenging.
BB again. What about the piston seal. You did not mention it in this article. Is this where it should be?
Does it work? – First paragraph – Last sentence
…That told me a few things, like the fact that everything was bone dry and the breech (piston) seal needed replacing.
RR,
The piston seal was worn out and I replaced it with a brand new one. That was covered in Part 1 of the B15 report.
If the piston seal is leather it can look bad and still work well. The B15 piston seal was completely disintegrated and needed replacing. I showed that in Part 1 which is why I didn’t mention it again in Part 2.
BB
The challenges you cite in fixing/restoring and keeping alive the “old gals” are very similar for those afflicted by vintage vehicle ownership, restoring and operation these days. We need more craftsmen – and women – who know how to use both brains and hands to get things done and done well. This is why FM applauds Mike Rowe in his initiative to introduce more craftsmanship and work ethic into the American economy. He ought to add gunsmithing and automotive mechanics to the STCC Foundation’s offerings.
https://www.stcc.edu/scholarships/mike-rowe/
BB,
Just so you know, I am quite impressed with the Bam B15. Though it seems to be lacking in accuracy, the quality of it is quite impressive. I would not mind owning that, even if it is Chinese.
I was reading HAM the other day and found out that there is an airgun dealer in Spain that wants to get in on the big price tag airgun market and introduce a new caliber to the airgun world, the 7mm. Though I am too old and not near rich enough to afford what he is trying to introduce, I do wish him well in his endeavor.
Of course, this does raise the question of do we really need a new airgun caliber. I mean recently, at least in my time frame, we have seen the introduction of the .25, the.30, the .357, the .45 and the .50. The truth is we are taking steps backward. Once upon a time, almost all airguns were PCPs and were what these days would be considered big bore. I have an 8mm hanging in my great room here at RRHFWA.
Some of the “old gals” were pretty small. I have seen mention of 4mm here. That is small.
Will we see these calibers return? Who knows. I am certain it will be decided by demand. It will also be dictated by the marketeers and whether they think we the masses will shell out the bucks for something “new”. Just take a gander at the powder burner world.
There is a TV program on the Motor Trend channel called “Roadworthy Rescues”. It is often fascinating to watch Derek bring old vehicles that have been homes for rodents for ages back to life and then, usually, try to drive them back to his garage from the junkyards. There is a process that he usually follows to troubleshoot and repair. Maybe we need a similar series called “Tote-worthy Rescues”, or something like that, for Airguns. 😉
Elmer,
With the settling of my sister’s estate I don’t have much extra time to look into things like this. It does sound like something that should be pursued.
BB
Frankly, this blog has a lot of potential contributors to a show like that. It might could be broadcast by the Sportsman channel. I mean, how many deer do we need to see be shot? Because that currently seems to be most of what they broadcast.
BB,
This whole blog can be summarized with one word: experience.
You said it yourself and other have said or implied the same thing.
Experience gives a point of perspective from which (sensitive, knowledgeable) people can recognize variations and guage the level of concern/impact the variations represent.
I was taught that to gain experience, examine the best and worst available examples of the product with ALL YOUR SENSES and the appropriate measuring tools.
When possible “test drive” both extremes to make the difference, good/bad more obvious.
Advertising propaganda can help with perspective as well. Our product does this (good); their product does that (bad).
Question everything. Every machining operation costs money, the manufacturer is not going to drill a hole without good reason… so WHY?
Most importantly, find an old guy to mentor you! 😉
Cheers!
Hank
BB,
This is a great topic!
I’ve found with springers I like to snug up the stock screws then note their (slot) orientation; I look after a few shots and ensure they are not loosening.
Ditto for open sights. I’ve seen open sights (non-click adjustable) where the elevation screw was unscrewing and lowering the impact point as I was shooting; Blue Loctite fixed that.
If the rear sight is drift adjustable, I measure its location with vernier calipers to ensure it doesn’t move while shooting. Note: on the low-powered .22 Haenel model 1 I got from Frank, the rear sight WAS moving when I shot the rifle, even though it seemed tight in the groove and required a small hammer and rod to move it.
Once windage was spot on, I used Blue Loctite in the groove and let it dry for 2 days and it’s been fine.
Blessings to you,
dave
Dave,
Tighten the screws. You have just alerted me to a Part 2 on PCPs.
BB
B.B.,
You pointed out your dislike for the roughness of the Ball Detent in earlier Blogs about the BAM B15 and again in this Blog: “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.”
You have only shown the barrel side of the mating point and not the breach end so i would ask if there is a slight ramp to ease the ball into the locking position?
Does roughness only happen on closing?
You can also try to compress the ball manually into the double staked blind hole to see if the spring is damaged, corroded or the blind hole wall is corroded.
Could also be dirt or dried grease/lubricant; so a flush might get it out from behind the ball. If it is corrosion a soaking with Ballistol might improve the rough feeling on locking.
Pushing a little grease behind the ball may also help after the flush and soak.
shootski
I am part of the research first group. I will scour the web for information while a gun is in transit. This would not work as well for someone like BB who is testing guns that are just coming out onto the market as he often does. For me, I am usually one or two generations behind current technology.
David Enoch
B.B.,
Hope you can do a review of the Air Venturi OmniStorm which is slated to come up in June, looks interesting as a pressure adjustable gas ram break barrel it may be interesting. https://www.pyramydair.com/product/air-venturi-omnistorm-air-rifle?m=6532#13966 Thanks.
Mike
Mike in Atl,
“…it may be interesting.”
From the Shot Show AV information
.177: 1100 fps with 7-grain pellets (18.8 Ft/Lbs)
.22: 850 fps with 11.9-grain pellets (19.1 Ft/Lbs)
SOMETHING is not right about the .22 caliber pellet choice! I can’t put my finger on it just yet.
The OmniTune system provides an operating pressure range of between 205 and 550 PSI. Apart from altering the Muzzle Energy, this also changes the cocking effort required between 25 and 50 Lbs
50 POUNDS of cocking effort to get 18-19 Ft/Lbs!!! If i understand their information WOW; ever cock a springer that requires 50 Lbs (5.7 Nm) of cocking effort?
Of course we all KNOW that the buyers will be smart enough to NOT charge the gas spring to 550+ PSI….
i hope i’m proven wrong…maybe it will be accurate and therefore interesting?
shootski