Even @runefalk wrote that he uses a 9.5 gram hammer, excellent up to 165bar. I just have to decide how many grams the custom hammer must weigh, also because from the weight it will have, I will buy or not buy the Hi Power Huma regulator (if I decide to stop at 160 bar maximum, I could use the 9 grams hammer). I use the Crown and my other compressed air rifles only for precision shots, in shooting ranges or for fun (long range canister shooting) in the countryside, on my property. In Italy, hunting with compressed air weapons is prohibited and punished with prison and with a very expensive fine. My Crown is, as you already know, cal. 25 and is equipped with a 600 mm slug barrel. In Italy, the slug bullets cal. 25 are not sold (cal. 22 are also purchased with great effort), for this reason I only use JSB King Heavy mk1 and mk2 with 34 grains (2.2 grams) and, if I want to use lighter ammunition, JSB Exact King with 1,645 grams . For now I am obliged to use these ammunition, but I hope that in the future, slug ammunition will also be sold in Italy. My crown has 65J, as stated by the Swedish house FX, but I would like to raise the power of the rifle to at least 85J .... for this reason I want to do some work on the crown, but I don't know if these jobs we wrote about until now they are sufficient and, above all, if a 9 gr hammer and 160 bar of pressure are sufficient to obtain this power, in fact, if possible, I would not buy the Huma regulator. But now I have spent a lot of money on the crown and it is not € 200 that makes me poor, so I will buy everything you need to bring it to 85 / 90Joule with 2.2 gram JSB. This is my story.