EXPECTED POWER: 14.5 Ft/Lbs OR 19.65 Joules
Once I have received the Gamo Bigcat, I checked the muzzle energy of the gun immediately. It was giving 13.3 fpe with CP 7.9g Not bad!!The shooting experience however not so pleasing. Twanging and unpleasant vibration. Being a very lightweight airgun, the vibration actually transferring to my hand. So decided if I can do something. I striped it down.
It is very natural to see a Bend spring from GAMO like this. And next the seal
One may choose to change the seal.
As we all know Piston is the Heart of the Powerplant.
The better the piston =Better the gun shoot
So lets have a look at the piston.
So the progressive bulged. All piston of gamo has this problem. And I don’t know the reason why the spring has to be exposed so much.
The more the spring exposed the more sound it will create while shooting and also while cocking and de-cocking.
I noticed the OD of the piston also bulged. have a look.
So the end of the piston looks better? Wobbling is guaranteed and a definite impact on SD. Therefore accuracy will be compromised.
Lets see what else we can spot.
Not BAD. 2.5mm gap. While it will be cocked, think in a slow motion. The spring guide getting pushed forward and the spring that is inside of the piston will buckling heavily like this:
Which will create, harsh, twangy airgun. It will reduce the power and spring life. Spring will bend, crack.
I just did a small thing to change the GAMO characteristic entirely.
I CHANGED the Piston!!.
I took this piston http://target-tune.in/international/products/GAMO-High-Speed-Piston.html
The OD for TTI Piston is 24.85mm is an excellent sliding fit for 25mm GAMO. No Wobbling so better shot consistency thus the accuracy.
The ID of TTI piston is carefully made so while cocking the spring will enter inside the piston very smoothly. As you see the piston ID smaller than GAMO OEM piston for arresting bucking for better axial force and longer spring life. It also eliminates unessential twang.
Natural Spring Guide. You don’t have to but any extra spring guide. Your existing spring guide should do the magic with this piston,
After the piston installed, look at the compressed spring. There are still gap between coil to coil even though see how straight the spring is. More interestingly, you will be noticing immediately the smoothness while cocking and a solid piston smashing sound while firing. You will feel like you are shooting an expensive gun. As I told before the GAMO characteristic entirely changed after this.
I have got a 911 fps with crosman premier 7.9gr with TTI’s GAMO FULL POWER SPRING and that makes 14.5 fpe with a undoubtedly shooting pleasure.