Hi, one of my favourite airguns is the BSA Meteor, from Mk1 to Mk5.
They are really cheap; apart from nice Mk1's, they usually sell for about 75 dollars (at least, here in the Netherlands).
Then there's always some work to do to turn them into something decent. That's where the fun starts.
Usually they have been abused, being marketed as "junior airguns". Bent springs, way too much grease, decayed seals, scratched stocks... The paint on the metal is really hard wearing though. So that's usually fine. A great idea from BSA. Blueing is nicer, but with blueing most of these Meteors would have been binned by now. My Mk1 has blueing, but they soon stopped doing this in the early sixties, I think to reduce production costs. Millions of Meteors were sold worldwide.
Anyway. They're great for learning about tuning. Really simple to dis- and re-assemble. No need for a spring compressor, although it does make life easier. Lots of parts available. Lots of things to try. My "winning formula" is: polishing the inside of the cylinder, the outside contact points of the piston, the slot in the piston, the cocking slot, the cocking shoe, the trigger sears. First I use a diamond file, then very fine abrasive paper, then Autosol polishing paste.
A new spring. I get mine from Protek Supplies in the UK. Perfect length and strength. Then I've had delrin spring guides and top hats made. A steel beer can piston sleeve works well too, in order to reduce spring vibration (see photo). But I think a well fitting spring guide and top hat has less chance of causing problems?
For .22, I make sure the transfer port is 3 to 3.2 mm. A friend of mine fits a screw at the rear of the scope rail.
I add a washer in the hole where the barrel latch spring and pin go. For a stronger barrel lock up. A new breech seal.
A quad ring as a piston seal. Meteor cylinders are made from a sheet of steel, brazed together. Never perfectly round. So a quad ring, which is sort of an o-ring with 2 sealing surfaces, is much more efficient. This becomes very clear when you put your finger on the transfer port, and move the piston up and down. With the quad ring, this causes vacuum on opening and air pressure on closing. With the standard seal, air escapes past the seal, which can be heard and felt.
Meteor barrels are good, but I use carbine length Lightning/Supersport barrels.
The trigger can be adjusted. My "powerful" Meteors do have quite heavy triggers. That's 10 ft/lbs in .22. I prefer my Mk5 which produces 7 ft/lbs in .22. I know it's a low figure, especially for American standards, but the gun is really smooth and accurate. Light and predictable trigger. And that power is more than enough for accurate shooting up to 30 meters, and plinking up to 50 meters (perhaps more, but that's my maximum range). Unless there's too much wind, I hit what I aim at (not smaller than beer can bottoms though hehe).
All in all, a lot of gun and a lot of fun for the price.
With some interesting history.
All of these adaptations are thanks to the legendary airgun mastermind John Bowkett. He tuned a lot of Meteors in the eighties, for about 20 pounds. Via the airgun magazines. I've tried really hard to find a "Bowkett Meteor", but people hang on to them.
Any other "Meteor lovers" out here? And perhaps other tuning ideas/recommendations?