Unlike Crosman, Gamo doesn't offer drawings on how to take there rifles apart. It would be hard for anyone to tell you how to take your apart, because you didn't say which model you want to replace the spring in. So I suggest one of two choices. Go online and do a search for "airgun repair" and locate someone who repairs airguns near you and take it to them, or contact Gamo customer service directly and see if they will send you a parts drawing of your model. ( See the link below.)
Start with the Gamo home page "Gamousa" customer service contact. Or see the link below for shops that repair air rifles.
You can purchase a Gamo air rifle at your local Walmart retail store. You can also purchase one online from the Amazon website and have it shipped directly to your house.
Gamo makes a dozen different rifles and pistol's. I find then to be of Very Good quality. I personally prefer the Nitro piston models over Spring. The new Dynamax (PCP) looks promising but expensive.
The Gamo Silent Cat fires .177 caliber Pellets not BB's.
If it's a C02 powered system then yes you can dry fire it. If it's a spring powered system the NO do not dry fire it. It will damage the system.
I suggest you contact Gamo Customer Service with this question. See the link below
Gamo is a manufacturer and retailer of air rifles. They also make and sell a variety of air rifle ammunition and accessories, such as targets and magazines.
I would contact Gamo directly for the best answer. See the link below. You do mean "GAMO" not Gamco
You will have to contact the maker to find out.
Best left to a trained person.
Get a GR3T trigger for it. It is considered the very best trigger available for Gamo. See the link below
Gamo never made a Sniper model rifle. It depends on the model, each one is different. You need to locate the model number and ask your question again.