I had a few thoughts in mind; all gun mounted. The CO2 setups I saw online seemed complicated and heavy, so...
1) Electronic. Batteries could be put in a pocket if weight becomes an issue. However Lithium Ion batteries are light and the 795 has a hollow stock.
2) Either touch or sound activated. Probably touch for proof of concept and then sound activated (similar to the Laser Lyte) for the final solution.
A) RC hobbies have a number of linear and armature servos that would have the power to cycle the bolt. The servos are light. Getting one with both enough power and speed to eject the snap cap shouldn't be an issue. But mounting it without cosmetically messing up the rifle might be a problem.
B) There are also wires (I don't recall the name) that contract when an electrical current is applied. That would be very light and potentially much easier to mount. But I know nothing on the characteristics of the wire or if it would be suitable to the purpose. It is just an idea to check out.
C) Combination devices, such as a servo that tensions a spring and then the spring provides the speed and power to cycle the bolt. The problem would be the complexity &/or machining needed might be beyond what a DIY project should be.
D) A solenoid device. (But that might be heavy and noisy.)
Anyway, I am just thinking aloud. I already have too many projects on the to-do list - and some are not optional :-) At best, it will be awhile before I can do much with the idea.
If you think any of my ideas have merit and want to check them out then let me know. I can expound on the ideas a bit.
NRA Life Member
"There are some ideas so preposterous that only an intellectual will believe them." - Malcolm Muggeridge