Hi peddy,
Shedtuner replied to my Meteor thread in the Collector's forum yesterday, and referred me to this thread:
http://www.airgunbbs.com/showthread....wer-BSA-meteor
Lots of info in these threads too:
http://www.airgunbbs.com/showthread....t-tuned-Meteor
http://www.airgunbbs.com/showthread....ght=bsa+meteor
Yesterday evening I spent about 5 hours (didn't sleep very long hehe) working on my Meteor. I was determined to get a few things done, and the result is already amazing.
I deburred and polished the relevant parts (inside of cylinder, inside of piston, outer contact points of piston, cocking slot of cylinder and piston, spring ends, trigger, sears, cocking arm shoes, metal rings. Using diamond files first, then 1200 wet & dry, then 2000 wet & dry, then Autosol metal polish) Fitted a nylon spring guide and top hat from Chambers. New piston buffer washer. New piston seal. Increased preload of barrel latch spring (slipped in 2 washers into the barrel latch hole). Adjusted the trigger so that it only needs a gentle squeeze, but it's still safe. Cleaned the barrel with my Napier pull through kit.
The result is not so much more power (I'm up 1,1 ft/lbs from 7,4 to 8,5 in .177; constant in the 660's ft/s).
But it is so much smoother. Before, there were noises during the cocking operation. Not anymore.
The recoil is less. The trigger is good enough now. I can pull it without the rifle going off target.
The barrel lock up is much better, all in all it feels like a much better gun.
Can't test accuracy yet; will do so over the weekend.
Next actions are: install scope stop screw (like John Bowkett did, a screw at the rear of the action). Enlarge transfer port to 3 mm first, then perhaps more.
Machine a piston weight. Use a quad ring (this is what JB used; a piston seal that has 2 sealing surfaces, instead of 1 on a conventional o-ring; should be better as the Meteor cylinder is never going to be perfectly circular due to the steel plate construction). I have found quad rings that should fit; they are on their way. A HW piston seal from Knibbs will arrive soon (25,5 mm is what I found). And a red heavy duty HW breech seal. I'll take 2mm off a spare piston head for a longer stroke, to test.
I'd like to put a bit of Loctite on the front and rear stock screws, as I find they come loose very easily with vibration of the gun (the type of Loctite where screws can still be undone with tools; blue Loctite?).
It's a nice little project. Oh I also thought about making a Coca cola can piston sleeve. There isn't much room for it though in the piston. The rifle performs well without a sleeve. Might try a very thin ptfe sheet sleeve later. Also some piston buttons from Maccari. Lots of things to try out. Any other ideas, please let me know. I'm sure there's more to experiment with.
Btw I finally got some good mounts for it: 13mm Sportsmatch mediums (lows would be better, but I couldn't find them). The Hawke Airmax 2-7x32 is a good scope for the Meteor.
Cheers, Louis