Tuning Gamo Big Cat accuracy

My neighbor has the Gamo Big Cat in 177. I asked how he liked it. He hates it. He said he would have better luck throwing a rock at a squirrel then hitting it with the gun. He said shooting a box at 20 yds looked like a shot gun blast. He's shooting crosman premiers theyre old and don't have the grain on the can. Without a chrono I said we should try getting some different pellets like the RWS 8.2 wadcutters and see how that treats it. Maybe they'll slow it down and in turn pick up some accuracy? Is this the right road to go down? He's not into tearing it apart to mess with it.
 
If he has tried one type of pellet and it is inaccurate, he should try several different pellets before deciding what to do with it. I have a Big Cat in .25, and it likes two pellets of any of the several .25 I tried. It prefers 26gr AA and since I had some H&N Spitzkuglen that were accidentally sent to me, I tried them, nothing shoots better than that. Only rifle I have that shoots pointed pellets well. I got the .25 since word was it has a BSA barrel, I wasn't disappointed. Since .177 has practically an infinite selection of pellets, look for trial packages and go for it is my 2 cents. Try different holds as well, and make sure that barrel droop hasn't caused the scope to be adjusted up until the reticle is floating.
 
Crosman Premier Hollowpoint 7.9gs from Wal-Mart seem to be one of the better tested pellets shooting in the low 900 fps in the Big Cat. Be sure he has 500 rounds break in shots and a good replacement scope and mounts that won't creep and all of the stock mounting screws tightened and lots and lots of practice and patience before criticizing it.

Be sure he holds the barrel at all times while cocked and loading the pellet with the other hand for safety that's not shown in this video.



https://youtu.be/0dQ44J6LlTA




 
As an avid Gamo shooter (multiple models and years), I’d say have him get JSB Exacts and start the relationship with the gun over. It won’t get much better then JSB Exacts or HN FTTs. Not saying it can’t get better but those will shoot. I can easily shoot a shotgun pattern at 20 with cheap pellets then tighten it up to cloverleaf holes at 20 with JSB Exacts. Standard weight, I wouldn’t go heavy yet but that’s just me. Now once he does that and likes his gamo again... then we can talk about the trigger and rest of it. 0:) 
 
He's bringing the gun over later. I'm gonna put another scope on it for him. I found a new tin of Premier hollow point 7.9 that's all I have in 177 around here. Odoyle said he likes those in this gun so I got lucky there. I had a TX200 so I learned how to hold and shoot springers from it. That was my first springer that I put a scope on.. I'll probably start by cleaning the barrel because I doubt he ever did. Check the screws and such trade the scope and see how that works. I forgot about the break in period. I doubt he's shot it 100 times in 2 years. I hope this works. Just so I have one up on him. lol I appreciate all the help. I think this will be fun
 
I worked with it a bit last night. Scope was definately a problem. I have it down to about a 2 inch circle now. It was way dark out. so I quit. Oh that 2 was using the 7.9 premier hollows It was only about 18 yds though. Between that trigger and the way that gun kicks. It's a whole new game for me. I'm use to my Akela and then a TX200 mk111 I'll ask him about changing that screw out for the trigger. I'm gonna screw with it again today. I'll sight it in at 20 see how that works out. It's funny, that thing is like shooting a fricing 410 compared to my Akela and this gun is a 177 lol
 
Everyone seems to like those hollow points but they have never gave me good groups with my gamos. JSB Exacts however or HN FTTs are always good. My personal rule of thumb is if it doesn’t shoot decent with those then it’s going to be a money pit making it shoot right. I also polish sear contacts and install the GRT trigger. The screw mod isn’t the same but it can help especially if you polish the sears and apply molly and mod the spring a little. Good luck