If you like a fixed barrel but have reservations about a sliding breech...you may be a candidate for a classic tap-loader!
A loading tap is a simple rotating plug that fits across the breech, with a hole drilled across it to accept the pellet. When open, you drop the pellet in head first to load. Rotate the lever back 90 degrees; the pellet is aligned between the transfer port and barrel bore. This is, IMHO, the safest springer mechanism ever invented - because an open tap
completely blocks the transfer port. Even if you deliberately pull the trigger, it's physically impossible to discharge a pellet, or slam the action shut.
To shoot, operate the cocking mechanism (underlever or sidelever), then immediately close it and open the tap - your digits are never in harm's way. As long as the lever is up (where it also serves as a handy visual reminder!), you can carry even a cocked and loaded gun in perfect safety.
The basic idea has been around since the classic BSA underlevers of the early 1900's, and for decades thereafter most manufacturer's top models were tap-loaders. Here is a Webley Tracker sidelever from the 1980's, and shots of its loading tap open and closed.
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