Hello Gilberto, maybe you got one of them FAC versions that means full power. If so you got lucky, but don't get caught with it. Do you own a chronograph? That could tell you exactly how fast your Gamo is shooting. If not, there are some really inexpensive ones around 20 to 30$ available on Aliexpress i own one of them, their measurements are in m/s so that would be even good for you because in Europe it goes by that and not fps. There are not feature laden like the expensive commercial products but for occasional use they are doing just fine. Let me see if i can find the link for the one i got form them. I will post it than later.
Hello Gilberto, yes this little Chronys work quite good, like said before they show the results only in m/s and not in fps, so over here is the need for converting it into fps, but there was some good excel spreadsheets from some member here that covers that really good. Yes they don't have any fancy features like the big Chronys. I for myself write them m/s results down, and then after i'm done put it in that excel spreadsheet, and have the correct fps numbers including the fpe numbers. So it is a little more effort involved with it, but not that bad. And so far i have not had a malfunction, i have no direct comparasion to a big $ Chrony, but some members here have compared it directly to them and they came up with only a few fps difference with the cheapo model. Like i said for what i'm using it, it is working just fine. Just checking once in a while if my guns shooting in the right fps range or need some attention if they fall off. I can just say if you don't want to spend a lot of money, this is a good buy for us budget oriented people. Well maybe they have stamped the F sign on it accidently i don't know, to get a real answer to it, you have to chrony it. Maybe you know somebody who owns a Chrony and he can help you out.Good luck and enjoy your new gun.
ok here is the link to that thread.https://www.gatewaytoairguns.org/GTA/index.php?topic=151661.0It is a long thread and was started last year, but there is for sure a lot of good info regarding this low budget model chrony in it.Have fun reading it.