Idle Thoughts: Redesign an airgun "Bell Target" for .22 Rimfire?

[Beyschaefer]

I've run across a very neat target, geared for 7 yard, indoor, airgun shooting that I would just flat LOVE to build and have at our club for outdoor 25 yard rimfire shooting (offhand, mostly...)

The English "Bell Target", BELL TARGET SHOOTING

I've come up with a number of mental "doodles" to make the "center hit" strike a bell for a nice "ding", but my concern is SAFETY, SAFETY, SAFETY!
At 25 yards, I'm concerned that a flat plate (non-moving) would result in little hunks of lead being redirected in undesirable directions...

I'd love to hear anyone ELSES ideas for this kind of target (front plate for the " 2, 3, and 4 rings" and a hole through the plate letting a perfect shot hit the center "5 ring" that slaps a bell for a nice, clear, absolutely unmistakeable DING!
I'm hoping to have this available for Juniors to try when paper targets start making their eyes glaze over... and my local range doesn't allow "trash" targets like bottles and cans (nor, in my opinion, should they, given how few people pick up after themselves...).

Angle the front plate? How steeply?
A 10" or so deep "catch box" in front of the target plate, to capture lead bits, is a given... but what angles of plates for safety?

Thoughts appreciated... even if your thoughts are "you'll never make it safe enough for rimfire at 25 yards... ". Of course, I'm hoping for a different answer... ;-)

 

[TOP PREDATOR]

how about (shooting from the hip) a front plate being your normal scoring area, the center being the hole, with a smaller plate behind it. on the smaller plate behind it, have a perpendicular rod that's threaded. get a spring that is captured by the second plate slipped over the rod. in the back of the "box" there is a hole which the rod goes through, with just one nut on it. the rod has to be longer than the surface of the back of the box, of which a bell is attached to. the pellet goes through the whole, pushes the next plate with the rod that pushes through the hole in the back of the box, striking the bell. the spring then resets the second plate. sort of like a semi auto recoil spring / rod combo.

or just a lightweight door hinge welded to the front plate in the opened position. you get a center ring hit, flaps up the bottom of the hinge, strikes the bell, gravity resets.

you don't have an idle thought, i think it would be neat having a reactive plate with a distinct "ding". of course an angel gets it's wings with every center hit splatter.