maxim552 wrote:
looking at buying a Umarex Fusion 2. its detuned for canada to 495 fps. is there anyway to untune it to stock, tia geoff
Short answer is Yes. It will have similar characteristics to any airgun, in that you should increase hammer strike to allow more "air" from the cartridge to the pellet.
I am unfamiliar with this gun, it may have a hammer spring adjustment, but I suspect it is accomplished by a shim behind the hammer spring.
The only way you will know if you are going forwards or backwards is with a chrony. There are cheap ones on
https://www.amazon.ca/dp/B0BN46KPNT?psc=1&ref=ppx_yo2ov_dt_b_product_details for 50 bucks. To modify your gun this is important.
Your goal is to hit the tak valve harder to open it more and release more greenhouse gas. First I suggest before anything else that you download an exploded view of your gun. This will show any shims or adjustment points, and part numbers for a stronger hammer spring, if any.