Meteor Musings

[Dornfelderliebe]

After a recent thread, T20 suggested I should outline what I did to get a Meteor to 11Fpe.
Before I start and for the avoidance of doubt this is to raise the power to an absolute legal amount, and comes from collating tips from other people as well as my personal experience.
By the way I've just spent money I do not have on a nice Mk1 more of that later. My account is mostly for a .22 Mk4 bought from new in 1975.
Step 1 buy a new OE Meteor spring from John Knibbs. I did not want to do anything that would overpower the gun and make it harsher. I spent a lot of effort filling and polishing the ends and radiused all the edges at the very ends.

Step 2 A thorough polish up of the cylinder and rear end of the piston as per usual with me that's just progressively finer wet &dry starting with 800 and ending with 1500 then a bit of solvol. I could not get any dowel to shove the wet &dry down and used plastic plumbing overflow pipe.
Now here I got the inside to a mirror finish which I think suited the O ring seal. Other people want a rougher surface finish. What do you think?

Step 3 long stroke the gun by filing the piton head flat. This takes the curved edge away hopefully reducing lost volume. Without measuring gear I think this yielded only 2mm but it's still an increase in swept volume.

Step 4 Fit a quad O ring ( I got mine from Seal supplies on the bay) I'm sure this made a big difference because of it's ability to seal a possibly out of true cylinder.

Step 5 Enlarge the transfer port very slightly. Here I confess that I used a very fine hand file that I crudely measured against a standard ruler at 3mm just less than 1/8 inch, When I next take it apart I shall use an exact 1/8 drill bit as I did when I did my Mercury. I have since read that the Cardews experimented properly on transfer port size and found 1/8 to be optimum.

The file made a nice smooth surface but I could not resist following it with a rolled up bit of wet & dry just in case I made the port smoother for better air flow.

Step 6 fitting a Weirauch breech seal from Knibbs as I read it held pressure better than the BSA item.
Before reassembly I very carefully deburred the cocking slot edges which made it smoother especially after fitting delrin spring guide and top hat.

At this point I thought I was pleased with myself and took it to SFS when picking up my 99 they tested it at 11.2 corroborating my chrono's 11.

I've used it quite a bit since and after the bash was disappointed to find it had dropped off slightly, there was a recent post about putting a piston weight to increase power, I bought and filed to fit a 4mm M8 washer. Whether it is the extra pre load or not this pushed the power back to 11 Fpe.

Do you wonder whether the spring had taken a set in this time, shortened slightly and lost power?

I still have not been able to improve the trigger which brings me back to the Mk1. It's trigger is far better fairly light and progressive. I guess the good mechanism went the way of 60s and 70's cost cutting.

n.b the gun is low powered at the moment 400 fps in .22 but apart from a patina developing looks to have been looked after. The low power could make the trigger lighter but I suspect it is just better.
Any thoughts please?

Has any one any tips on tuning the Mk4 and 5 triggers? I have a mK5 for bell target and the trigger is worse than the Mk4 I gently polished the top rear of the sear which did help slightly but of course you have to be ultra careful not to overdo it. So I did n't. The Mk 5 is heavy and so indistinct it's almost like a two stage before it finally lets go. I am beginning to adapt to it.

[T 20]

Nice write up, Sir.

Unfortunately, though I have a few Meteors they've never floated my boat enough to play with them --- I'm not knocking them, it could just be that I have no sentimental attachment to them.

I do remember buying my first Meteor for £2 in 1976 off a mate of mine --- he also had three bolt action repeating air rifles in some weird caliber that I decided not to buy at £5 for the three.



All the best Mick

[NOTSHARP]

Very interesting, Thank you.

I have a Mk.1 in .177 flavour, bought off a workmate in 1967, for £3. It was only about five years old then, and little used, but when on a wage of £5, that was an expensive buy for me.




I did give it a lick and polish a few years ago, only to the extent of spring and seals. I have no idea on power, I did not own a chrono at the time.

Now you have got me thinking.

But, not until the Airsporter is sorted.


Steve.

[GB2017]

Thanks for taking the time to do this, have 3 meteors that need looking at when I eventually get around to them, will be referring back to this for sure

Atb

[TonyL]

Nice little write up, sir.

Yes, I'd guess the slight power loss you experienced was due to the spring setting. And, as you've seen, easily remedied by the addition of a little more preload.

Keep on tinkering!

[Gerry B]

Very interesting, Thank you.

I have a Mk.1 in .177 flavour, bought off a workmate in 1967, for £3. It was only about five years old then, and little used, but when on a wage of £5, that was an expensive buy for me.




Steve.

I have one almost identical, but when I was given it, no rear sight !!!

I've tried many of the shops and forums, with no joy, however I was given a very old BSA scope, the tiny thin tube one, with the wide mount, so the rifle looks fairly "period".

I've never opened it, or shot it much, so no idea what power it makes.

Enough to punch paper at 15 years when I sort of zero'd the scope !!!

Now , It hangs up on the wall in my workshop .

[Shed tuner]

From a while back:

https://www.airgunbbs.com/showthread...wer-BSA-meteor

The synthetic seals massively improve these !

[Dornfelderliebe]

Well done shed Tuner. I have no idea how to make the carrier but this is a master class on Meteor tuning.
It also touches on the subject of a breech bolt and the hollow ends. I can't think how to strengthen them.
Ps 'scuse my French

[Shed tuner]

I did think about making top hat type inserts for the breach bolt/pin, that are supported on the inner face of the breach, with the "brim" sitting in the outer jaw recess. Thread one, and bolt through the other. Then I got tired of the trigger and sold it

[Dornfelderliebe]

I did think about making top hat type inserts for the breach bolt/pin, that are supported on the inner face of the breach, with the "brim" sitting in the outer jaw recess. Thread one, and bolt through the other. Then I got tired of the trigger and sold it

I was very surprised how much better the trigger is on the Mk1

[maximus]

I did think about making top hat type inserts for the breach bolt/pin, that are supported on the inner face of the breach, with the "brim" sitting in the outer jaw recess. Thread one, and bolt through the other. Then I got tired of the trigger and sold it

I'm no expert on meteors but the one I worked on for a pal had hollow breech forks so threading them wouldn't be possible. Real el cheapo manufacture.

[Shed tuner]

I'm no expert on meteors but the one I worked on for a pal had hollow breech forks so threading them wouldn't be possible. Real el cheapo manufacture.

yes, hence threading the top hat bushing instead...

[maximus]

Ahhh I getcha

[T 20]

Unfortunately, though I have a few Meteors they've never floated my boat enough to play with them

Oh, I've just realised that's not completely true --- I built a Meteor-b2 hybrid.

I used a b2 barrel and cylinder and fitted a Meteor piston, trigger assembly and Meteor MK5 stock to it --- I'll have to see if I can find it and have a play.




All the best Mick

[Dornfelderliebe]

I'm no expert on meteors but the one I worked on for a pal had hollow breech forks so threading them wouldn't be possible. Real el cheapo manufacture.

I regard this as a character feature.