The safest way of doing this is to strip your gun down and start replacing stuff. Adding high quality items like reservoirs lubricants, seals, valves, etc etc will give you a huge increase in power. If you feel like risking it though you can try (if you have a PCP or CO2 gun) rigging the release valve to only let higher pressure through, or modify the connecting outlet to allow for a bigger tank (that only works if the gun does not have a specific power setting, and instead just opens the valve for a set amount of time).
Keep it clean and get a stronger spring.
NO
No
you dont
Yes. A&K and one other company make an airsoft gun based on the design of the Magpul Masada.
At your house LOL.
I would highly recommend that you do not make your own airsoft pellets. They might jam and or brake your gun.
An Airsoft gun
Because you, my friend, have a broken airsoft gun.
no. Airsoft guns could not possibly shoot that fast.
Not worth it. You may damage your gun
youtube it