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Ammo BSA Meteor: Part 5

BSA Meteor: Part 5

by Tom Gaylord, a.k.a. B.B. Pelletier

Part 1
Part 2
Part 3
Part 4

BSA Super Meteor
My rifle is actually a BSA Super Meteor.

Today’s report is really interesting — at least I think so. If you want to know more about what’s behind the performance of a spring-piston air rifle, today will give you some insight.

In the last report, I installed the new piston head with a new seal and buffer. This head has a threaded shank with a nut to hold it to the piston securely. It replaces the old head that was held on by a flimsy E-type circlip that had failed. And you may remember that after the head separated from the piston, people continued to cock and fire the gun, not knowing what was wrong. The result was a lot of mechanical damage, including broken welds on the piston and heavy galling inside the compression chamber and spring tube.

After the rebuild (with a lot of help from my friend Otho), I fired the rifle and noted that it seemed okay, but it would have to wait for a run over the chronograph to know for sure. Today, we’ll do that run.

Before I did any shooting, I cleaned the bore with a bronze bore brush and J-B Non-Embedding Bore Cleaning Compound. It was filthy to begin with, but I was surprised that the brush went through easily from the first stroke. Usually, it takes 10 strokes or more before the brush loosens up.

Once all the paste was cleaned out of the barrel, it was much brighter inside, though not as shiny as a new barrel. I don’t have a borescope; but to my naked eye, the bore on this rifle looks very uneven. If this were a firearm, I would suspect it had fired a lot of corrosive ammunition and not been cleaned properly. We’ll see what that does to the accuracy in the future.

Pellet selection
I initially selected three different pellets for this test. Two of them were lightweights, and the other was a medium-weight pellet; but as it turned out, I never got to test the medium-weight pellet. I learned so much from the lightweights that I was pushed in a new direction.

RWS Hobby
The first pellet I tried was the 7-grain RWS Hobby. The Hobby is a lightweight pellet that normally goes faster than any other pure lead pellet. I use it in most of my velocity tests to give a good idea of the rifle’s power. I expected to see something in the high 400s or low 500s with this rifle, but that’s not what I got! Look at the first 3 shots.

337 fps
337 fps
350 fps

Obviously, Hobbys were not the right pellet for the Meteor. They fit the breech tight and didn’t seem to want to move very fast.

JSB Exact RS
Next, I switched to the JSB Exact RS pellet. While this 7.33-grain pellet weighs a little more than the Hobby, it fits the breach much looser, and I felt it might have higher velocity. Let’s look at the first 3 shots.

312 fps
343 fps
357 fps

Clearly something was wrong! I felt the tuneup should have given me more velocity than that. I took a look at the breech seal, which had not been replaced. It was flattened even with the breech but didn’t seem to be damaged in any way. However it seemed like a good idea to pull it out and examine it closer. That turned out to be exactly the right thing to do!

When I pried the seal from the breech, it fell apart! The Meteor’s breech seal is a synthetic circular seal that’s taller than an o-ring; and from appearances, this one is at the end of its life. I didn’t have a replacement seal on hand, but I know how to make breech seals out of leather. I had a couple of my homemade leather Diana breech seals on hand, and all they needed was some trimming to fit the Meteor. The first one was trimmed too small and gave me several shots at 216 f.p.s. Obviously, it wasn’t doing the job!

BSA Super Meteor breech seal
The Meteor breech seal disintegrated when it was pried out of the breech. It wasn’t doing the job anymore and needed to be replaced.

The next leather seal was left larger and just stuffed into the breech seal channel. It fit the rifle much better, while still standing a little proud of the breech. That’s what you want in a leather breech seal. This time I decided to oil the seal thoroughly before continuing the test. I applied several drops of silicone chamber oil about 10 successive times and allowed it to soak into the leather. Then, I left the gun overnight with the breech broken open to allow the leather to completely soak up all the oil, while not flattening out. The next morning, I oiled the seal one more time. Then, it was time to shoot.

The first 3 shots with JSB Exact RS pellets the next day were very revealing:

522 fps
510 fps
485 fps

I was on the right track, but maybe the job wasn’t finished. Even though the JSB Exact RS pellet fit the breech looser than the Hobby, I wondered if deep-seating would improve the velocity. The next 10 shots are all with the JSB Exact RS pellet seated deep in the breech, using the Air Venturi pellet pen and seater.

509 fps
494 fps
500 fps
481 fps
496 fps
480 fps
470 fps
446 fps
416 fps
408 fps

Time for learning!
Okay, what have we learned from this? I think an examination of this last shot string shows the gun wants to shoot a little faster than 500 f.p.s. with this pellet, but it isn’t for some reason. You notice that the velocity drops as the shots accumulate. What’s up with that?

It seems to me that the new breach seal is losing its ability to do the job as the gun is fired. An examination of the seal shows that it’s flattening out, but I didn’t want to accept this conclusion from just one string of shots. So, I returned to the RWS Hobby pellets next.

RWS Hobby
Because they fit tight, I also deep-seated these pellets with the pellet seater:

332 fps
344 fps
335 fps
379 fps
397 fps
363 fps
370 fps
373 fps
360 fps
373 fps

I’m not sure what to make of this shot string. It looks like the Hobbys wanted to go faster, but then they sort of stabilized around 360 to 370 f.p.s. I doubt if they’re going to go over 400 f.p.s. with the current breech seal.

The adjustable single-stage trigger breaks at 4 lbs., 9 oz. as it’s set right now. Because this trigger adjusts by varying the amount of sear contact area, I plan to leave it right where it is, for safety’s sake. It’s crisp enough that I can work with it as is.

What to do next?
Based on the evidence I see above, this rifle now wants to shoot in the low 500s with light pellets, but the breech seal is holding it back. If that’s true, a new breech seal should push the gun back up over the 500 mark. The solution seems simple. I went online to T. R. Robb’s website in the UK and ordered 3 new breech seals. Since they’re synthetic, I don’t know how long they will last…but 3 should last me the rest of my life.

I’ll be very pleased to get a final velocity around 500 f.p.s. with lightweight pellets. Remember, I want to shoot this Meteor for fun — not to obtain the absolute last foot-pound of energy it can produce. The trigger is heavy but also very positive, and a delight to shoot. And the rifle fires with a pleasingly dead-calm shot cycle.

I have no idea if this rifle is worth the money, time and effort I’m putting into it, but I’m doing it as a learning exercise, rather than just restoring a BSA Meteor to usefulness. If I wanted a Meteor to shoot, I would have been money ahead to just turn this rifle into a parts gun and find a rifle that was in good condition to start with.

I guess the analogy to what I’m doing with this Meteor is the guy who finds a rusty old tractor laying out in a field — abandoned for decades. It isn’t worth the effort, but if he can get it running again, think of all he might learn along the way.

author avatar
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.

43 thoughts on “BSA Meteor: Part 5”

  1. ARH’s HW breech seal is great for the meteor, Original HW seals are good as well. Sometimes you have to shim or trim the seals, that applies to the OEM seals as well.

    • I do as well, having several tractors and old machines. Sometime sit down and reflect, and add up what you make gross in a year, and then take out what you have to pay out in taxes, mandated fees,permits and mandated insurance, ect.. and see what you really have left for stuff for your family, and yourself. You will find that damn few of us have much left over to spend on life, or invest in anything. Makes me mad as hell, but the enternal hope of a sucess at tinkering on something keeps that reality at bay.

  2. I Have found with all the old BSA and Webley Barrels i have come across in .177 is that pellets have to be deep seated, as they are always a bit loose when sat flush. In .22 the barrels are actually 5.6 mm and not 5.5 mm and Eley Wasp’s which are 5.6 mm are rubbish, though Super Domes and Crosman’s when deep seated are pretty consistent and very accurate.

    I’ve recently repaired an old .177 Webley Hawk Mk II, and if i don’t deep seat the pellets they will just fall out if i tilt the barrel. All my .177 pellets i have at the moment were bought with either PCP’s and Multi pumps in mind. so i am going to have to wait till the New Year till i can get some Superdomes and the like. Actually i think you might find the piston head on this Webley interesting http://angryangryguncompany.blogspot.co.uk/2013/12/webley-and-scott-hawk-mk-ll-part2.html , and the breech seal on that one is around the transfer port.

    I also picked up a .177 Heanel Mod 1 with the safety and stepped ramp, spring loaded rear sight, so making it a much later Mod 1. I also remember reading some of your older blogs on making the leather breech seal and leather piston seals, i think the piston seals involved leather, water, a sized hole in thick wood, and a socket, as well as a few other ingredients. I should be able to google it, but if you could let us have a link that would be appreciated very much indeed.

    Yet again another brilliant blog on cranky old British air rifles, thank you.


    Best wishes, Wing Commander Sir Nigel Tetlington-Smythe.

  3. BB,

    in an emergency, I have used 2 o-rings to take the place of that high synthetic seal with no ill effects. I did that on the Crosman Nitro when I was playing with the crown and bedding the action just to see if the stock seal was causing any loss of pressure when firing. I obtained the same results with the two o rings nested in the barrel or breech cutout as I did with the synthetic, high seal. Just for your information.

    Fred DPRoNJ

  4. I was wondering when you was going to come back to this gun.

    I haven’t messed with repairs that much on spring guns. So the question I have I think the answer will be (No).

    But when the barrel closes and latches can the barrel be pulled in tighter to the the breech by some kind of adjustment? You tightened up the side to side movement if I remember right. But what about forward and backwards movement?

  5. BB,

    It’s interesting that you have the same declining shot velocity as I had with the LG55, but the problem is just the opposite. You have a bad breach seal and mine is like new with a good seal. I did get a new seal for mine, but along the way found that the mainspring is indeed broken on the LG55. No grinding or weird feeling behaviors when cocking or shooting it! The rear 1″ of the spring had tightly threaded itself into the rest of the spring on the spring guide making act as just a shortened spring. I’ve had other broken springs that just plain felt bad when cocking and shooting. Not this one…

    I can’t seem to find an original Walther mainspring to put back in it, so I’ve ordered some long spring stock that is close from McMaster-Carr. Anyone here know if an HW30 or 50 spring will work in case I don’t like what I’m getting? They seem to have write that’s a bit thick, but otherwise the dimensions should work.


  6. Well, I’ll give you full marks for perseverance! You might actually get to see why the Meteors have a decent rep as plinkers. Just wondering, is this an old style British 5.56mm rather than 5.5 barrel? I would assume yes. You might want to try it with some original Ely Wasps, which I think you have?

    • Oliver,

      This Meteor is a .177. Yes, I do have many tins of the old Eley Wasps that are 5.56mm.

      I do like the way this rifle feels when it fires. It’s reminiscent of the Diana 27, though not as smooth as my tuned 27. But it is very quick and clean. I really like it. If I can get it up to 500 f.p.s with light pellets, I will be completely satisfied.

      T.R. Robb has told me the breech seal is shipped, so I should have it soon. Can’t wait!


      • Tom,
        I kept waiting for someone to say, “Dude, no way should you be content with Hobbies at 500fps out of a Meteor Mk5 Super .177!” But no one did. My first springer purchase was a used Super .177 from Larry Hannusch back in ’86 or ’87. I still have it. Casual bench resting with a Bushnell Sportview 4x32AO yielded 10m 5 shot Hobby groups of around .2, and averaging in the 660-690fps range, depending on ambient temperature. Mike Driskill bought his first Diana 27 off the same “For Sale” list just before I bought the Meteor. How I envied him, but the Meteor was a fair consolation prize. Sure, the trigger was a little heavy and single stage, but it broke cleanly and still shames any out-of-the-box Gamo-type trigger I’ve ever tried. It was very light weight, even with a scope, and you could shoot it all day without wearing out your arms. I considered it my poor man’s Diana 27, but at least Mike would let me shoot his 27 whenever I came over.
        I bought a second Mk5 last year out of nostalgia, and shot it only in a plinking capacity in my backyard. I decided I didn’t need two (I know you’ve never had that problem!), and had it on my table down from you at Roanoke last September for a little more than the one you bought, if I remember correctly. Mine was only slightly less rough than yours in appearance, but I couldn’t give it away. I bought your friend’s custom 26″ Lothar Walther AirForce-compatible barrel with the permanent attachment.
        I just don’t want people to think the performance you are getting out of your Meteor, for whatever reason, is typical of this competent but slightly rough British classic. I don’t at all mean for this to be any negative reflection on what you have done with your Meteor, for, as you have demonstrated many times over almost 20 years, each airgun can have its own “voodoo” going on, and two apparently identical air rifles may display radically different behavior.
        Jess Galan had an airgun hunting article in Beeman’s first Airgun Digest, and he hunted rabbits with a .22 Meteor running about 500fps, which sounds right, though I don’t remember whether he mentioned what pellets he used in it. Thank you for taking the opportunity to spend time on this low dollar, minor classic that introduced so many thousands of young Brits to the pleasure of airguns.

        • Tom,
          I forgot that yours is a Mk4, not a Mk5, but the performance shouldn’t really be different, since the springs and basic configuration of the two marks are the same.

        • Lance,

          Thank you for that very thorough comment! I suppose if I had bought a Meteor that didn’t need all that this one needed I might be looking at the gun differently. With this one I have had my nose pushed deep into the pile and forced to consider everything.

          I know a Meteor IV or V should be faster than the low 500s. But I don’t care if mine is not. That’s all I’m saying. I purposely chose the thicker buffer to reduce the stroke, just to keep the velocity down low.

          Again, thanks for your comment.


  7. BB,
    It will just be that much more fun for you to shoot it when you do get it right! It looks like it will be as fun for you as my 490 is for me when you get done. The one problem with this type of air rifle is that they eat 100-150 pellets every time you pick them up.

  8. Looking at the previous articles in this series I read that the original spring was reused. I rebuilt my BSA MKV with a spring and seal from Jim Maccari at Air Rifle Headquarters. Prior to that pellets would only go through 4 or 5 layers of stiff cardboard and couldn’t punch through a beer cap. The pellets would also get stuck occassionally. It grouped about 1″ at 33ft. After I changed the spring and breach seal it tightened up to less than 1/2″. Unfortunately I don’t have a chrony to see how consistent the speed is. It shoots much crisper and is louder now. It can go through a beer cap and embeds itself about 1/4″ into a 2X4. I am using RWS Meisterkugeln and Superdome pellets. This series helped immensely in helping me take apart and rebuilding my BSA.

    I am reluctant to use a scope on it since the results were inconsistent. I had a Steoger and it moved around too much. I made some peep sights using the original rear sight and this is how I get the 1/2″ groups from a bench rest.

  9. B.B.,

    Last year I bought a Meteor (a MK IV or V) in as rough a shape as yours, although the dealer advertised it as recently rebuilt. I knew that couldn’t have been the case when I saw that it didn’t even HAVE a breech seal, let alone a disintegrating one! I should have returned it to him right then, but life got in the way, and too much time elapsed before I could reasonably ask this well-known dealer for a refund.

    Besides, after you began this report way back, I decided that I would use this Meteor of mine as a learning experience, using your blog as a guide. I have not yet started because of family issues taking up too much of my free time lately, but in the summer I will get around to it, PROVIDED, first, yours proves to be reasonably accurate. Mine has a bore in about the same condition as you described yours as having. Second, the trigger on mine is mess. For one thing it must be manually returned forward after a shot with my trigger finger (nifty pro rebuild, eh?), and it breaks at, I estimate, at about 1 1/2 pounds.

    My initial investment (for what, remember, was supposed to be a rebuilt air rifle) plus the price and shipping of parts you purchased for your Meteor, mine would end up being a $200 gun. Yep, a BSA Meteor in 30% cosmetic condition for $200.

    I still just might sell it to someone else as a project, although I would take at least an $80 bath on it. My other option is to use it as a bottle-rocket launcher each July 4th.


    • Michael,

      Well, this report should be of help to you, then! I’m sure I have over $100 invested in my gun at this time. But mine seems to be shooting fine now — we’ll see when I do the first accuracy test.

      Your trigger is missing the return spring, or it has been severely damaged. You can see what it looks like in the earlier parts of this report. It’s a hairpin spring and you’ll probably need one, so start looking right away. Maybe T.R. Robb has them, I never checked. But for sure you will need the piston head and the breech seal you have seen me install..

      Please keep us informed of how you are doing?


      • B.B.,

        I see I posted my comment in #5, not #6.

        I think the only way I will get my investment back is to consider it tuition towards my air gun maintenance and repair education. This particular “test bed” has the advantage of being a real mess at the start, so I have no trepidation about diving in, fearing that I might screw it up.

        When I was in my mid 20s I bought a brand-new $700 bicycle, an early mountain bike. After treating it with kid gloves for a week of use, I lent it to a friend who promptly scratched the frame down to the metal, but the scratch was only about two by a one sixteenth of an inch. He felt sick about it. I actually felt wonderful! Now my bike was no longer perfect, and from then on I was able to ride it without fear of putting wear on it. My friend did me a huge favor, and to prove to him that I was not just being kind, I bought him a beer, and then I took it for a ride on a trail and put a few minor scratches on it.

        If this were a Diana 27 or FWB 124, I wouldn’t dare open her up.

        Yep, I’ll keep you posted and even take pictures of my discoveries.


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