An authorized repair center might have what you want.
The Fast Deer is a Chinese made Air-rifle. It's model KL-B3. If you want more information go to the attached link at the bottom of this page.
It all depends on the condition of the air rifle. Without more information it is not possible to answer you.
Yes it can but getting the current rifle "Tuned" by an expert will get you better results. Tuning will make the spring and trigger perform better.
This rifle must be rare, I can not find any information on it. I did find the following information on these BSA rifles in Mint condition. ( Yes it would be a collectible) Goldstar $450 Superstar $420-$480
You will have to take it apart. Each model is different so you will have to find a diagram of the rifle.
It hard to find information about this line of air guns but I know they were made by "GAMO." I found a magazine add for a new one on the web that was dated 1972
Are you sure it's not a Benjamin air rifle. I know of "NO Jefferson air rifle company", But Benjamin air rifles have been around a long time. If so what is it you want to know.
There are a number of places that an individual can find BSA rifle scopes. Some of the places you may want to try include BSA Optics and Air Rifle Scopes.
The tuning fork produces sound waves when it vibrates in air.
Go to airsplat and you should find what your looking for. Or you could look up "air gun repair" on the web.
The only information that I could find is that Kral AV Industrial makes the Demon air rifle along with several others. The company is in Turkey, and has made air rifles along with real rifles.See the link below.
To increase the power of an air rifle, you can consider upgrading components such as the piston, spring, or air cylinder for higher compression. Additionally, tuning the rifle by adjusting the preload or using high-quality pellets can enhance performance. However, ensure that any modifications comply with local laws and regulations regarding air rifles, as increasing power may classify it differently legally. Always prioritize safety and proper maintenance when making modifications.