5 in a nickel @ 25yrds. Hmmm. I have 2 spring guns that can put hole in hole at 25yrds. I think your Hatsan hasn't found its favorite pellet.
If Hatsans are 1/2 the gun that Evanix Rainstorms are, then I want a double tank Hercules.
On a serious note. Are you shooting on high magnification, bench bags? I don't shoot on anything past 10x & prefer 6x or 3-4x to make use of 2nd plane focal scope mils extended shooting. I wish Hawke & good tough but cheap air gun scopes offered super fine reticles. I just had to correct testicles to reticles. Glad I caught that. Dam phone. Anyway.
I'm not knocking you, your rifle or skills but a GOOD shooting PCP & pellet combo to me is hole in hole benched at 25 yards. I start at 12 yards in basement. Use stacks of feeler gauges from top of receiver to bottom of scope. I use levels also but usually the gauges are dead on where levels can leave you off 1°-2°. I also Mic my pellet heads. Slug barrel. Work trigger to hopefully 1lb at most but 8oz is preferred.
So Dwight, nice to meet you. I've been around over 12 years now & this can be an addiction. You meet the right guys and used guns are dreams come true. I have an old timer friend. He buys, shoots, tunes & fixes up then sells for less than new when he gets bored. Example. He told me 8 years ago. Jimmy, just buy a Rainstorm II & you'll be happy. Well, I have his .22 with regulator installed. I have NO problem hitting within 2" at 150 yards & that's only 861fps w/ JSB 18.13'S. Under 30 ftlbs.
So again I'm curious about OP question not in used or new but how does Hatsan stack up against Evanix, Rapids, RAW. Not build quality. I know that. I mean accuracy, dependency, ease of changing out all o-rings, porting & self hot ridding or after market parts like HDD or power adjusting other than a reg. Best regs are most likely HUMA.
See Dwight, addictive. To this poster on his 25 yard groups. I've owned over 50 air guns. I'm down to 7. The ONLY ones that I can do what I said, hole in hole are a JIPA tuned El Gamo 300 that I cut recrowned the barrel at 10". John in PA's old TO1 48 both in .177. My JIPA tuned R1 is accurate but I either haven't found the magic pellet or proper hold for that much power. Oh and I'll say this.
I chased "better" when I've owned as good as it gets. 2 spring guns I'd be a Eunuch for to have back are the JIPA tuned .22 RWS54 & Zeus tuned RWS 34 Panther. 125 yards coke can every time & at 50 yards Zeus tuned Panther cloverleaf. The list of PCP'S. I'd want back are my 2 AZ Rapids & all Rainstorms.