Big Cat Consistency

[Boz]

Hey guys been reading up on allot of great info here and have recently purchased a Gamo Big Cat as my first shooter and have some questions.

My accuracy is all over the place, shooting from a bench with a soft pad to rest the gun on, at about 30 yards I can pull 3-4 shots within 1/4-1/2 inch then they just start opening up. I'm using the Gamo 3x9-40 scope with a 1 piece mount.  I've shot about 3 - 500 pellet tins through her and the consistency just seems to lack.  I'm primarily using the CPHP for pellets, which I have yet to hear anything bad about.  I was reading through the "Big Cat Blues" thread and was wondering if a barrel polish would help, it seems my groupings following a barrel clean with patches and goo gone hold tighter and start to open up over time. I've cleaned the barrel twice, as I know most ppl say don't clean it often I've found my accuracy increases after a cleaning.

A buddy of mine also purchased the .177 Viper, we have yet to sit down and fire his gun (He ordered the GRT III Trigger so its been apart in anticipation of delivery).  I see the Venturi Gas Spring for my big cat and was wondering how well this works for pulling more consistent shots / smoothing out the gun, and if it would also fit the .177 Viper as we cannot find a the gas spring anywhere that states directly that it will fit the Viper.  I will most likely send my gun out for tuning when the stock parts are worn out.

Over all we feel Gamo products lack in quality of build, although most Tuners seem to love them.  With a thorough tuning I can imagine these guns fire like a dream, its just frustrating that gamo would put out inferior products that need extensive work out of the box to make them reliable shooters.  Overall I want to love this gun, the look, finish, feel are all great. I will order my GRT III Soon as I'm sure its just as big an upgrade as everyone says.  My big question is would a barrel polish help with groupings and consistency, it does seem quite rough and like most other gamos my rifling ends about an inch from the end, where the crown begins.  Maybe the long break in period many speak of with the Big Cat is the barrel smoothing out? So why not save some time and polish it smooth.

If a polish is recommended, what technique / polish should be used in an air rifle barrel.

This damn Big Cat is like a game of Golf for me, shoots inconsistent but every so often it hits where I want it to, which gives me some hope and keeps me coming back for more!

PS  The cat ate 2 birds so far

[longislandhunter]

Welcome to the forum Brian, nice to have you with us....

My suggestion would be to pick up some different pellets and give those a try.  The problem may be as simple as your cat not liking the CPHP's.  They are pretty good pellets and most of my rifles will shoot them well, but I do have rifles that just don't like them at all and will spit them all over.  Each rifle is different,,, the best thing you can do is get an assortment of pellets and try em out until you find the pellets that the gun likes.  You can get a good pellet sampler form straightshooters.com   or some other places.  


The problem could also be with your scope.  If you have another scope try that one and see if the problems persists.  If the problem disappears then it's the scope,,,, if it doesn't then it's either the rifle or the pellets.  

My guess is that if you test some other  pellets you'll find at least a couple that will shoot great.....

Jeff

[Gene_SC]

Brian, it is not just Gamo. Most of the mass produced air guns have the same issue. It comes down to the fact that they are not built the same way as the true Euro springers are made. But you will be happy to know that all these issues can be resolved with a good tune. I have owned many Gamo and Chinese air rifles in which they were real tough to shoot until I finished the guns off with a tune. If you want a gun that shoots well out of the box, buy a BSA, Lightning, RWS 48, 52. But still even the RWS German made springers come completly dry from the factory. No lube whats so ever.

[North Pack]

Gene, - why is quality such a problem with these outfits? A tad of the right amount of grease isn't a huge expense, - labor or grease. Investing in good tooling (stamping or molding) isn't that big a deal for large companies with a good customer/sales base. Today I put a TRG Trigger into a new Whisper, - and one stock "screw hole" had been (roughly) widened due to a poor alignment/design between the barrel and the molded plastic stock. As a former/retired mechanical designer - this should not present a problem, - really.

[Gene_SC]

Well as a retired Mechanical Designer you should know that things change by the time they go into production.  The name of the game is money. Put as little as possible in and still have it function. The reason I think that RWS does not use lube is because they still have in there owners manuals to put lube on the spring every so often. If you figure the cost of lube put into all those guns they produce they would either have to raise there price or make less money and that aint gonna happen.

Personally I only have bought one air rifle in 4  years that shot perfect out of the box and that was a BSA Lightning. All others I have had to tune to get them to shoot decent.

From my prospective as an example. If I bought a R-9 new for $400.00, it would still need a lube tune at least. If I bought the Chinese clone B-26 and did a full tune on it, the cost would be less for the new B-26 and the tune together. And you would end up with virtually the same gun. Just one is made in Germany and the other is made in China. I like my B-20's and B-26 and my pocket book does as well.. Heck I could by 3 new B-26's for the price of one R-9.  ...

[Boz]

So its not only Gamo, most other makes require tuning before they are nail drivers?  Makes me feel better, because like I said I really do love the look feel and design of the Gamo.  It still ticks me off that I gotta spend the same amount the gun cost to get it to where I feel it should be shooting.

As for the gas spring, is it worth it, or is my best bet a good tune? Or both?

Ill try other pellets as well, the selection in my area is not great but I'll look around.  As for polishing the barrel, not worth the effort?

[airiscool]

I just bought a Whisper several weeks ago. Had the same problem, consistant for a few.... than what-the?  

I thought it was a combination of me, the gun wearing in and that #$%* trigger.

I made sure the scope rail and mounts were snug, which they were, but still inconsistant shot groups. The Gamo scope  had 'waves' for anything past 20 yards, which bugged me, so having better  scopes sitting around I changed it. A major  portion of the  inconsistancy went away.

Then I got some Super Domes instead of trying to use  25 year old Crossman pellets. The old Crossman pellets  had quite a range of how tight they fit into the gun. Some dropped in, most had to be pushed hard, and a few wouldn't go in at all. Tells me not to expect much consistancy there.   The Super Domes are much more consistant in how they fit in.

 Next was to put in one of the Tuna man's triggers.   BIG help with just that one change.

Now I don't have anything to blame poor groups on but myself.

Paul.

[speedturtle]

Hello there Boz, we almost have the same setup - a Gamo Big Cat with a GRT-III trigger and just using the plain cheap CPHP as its main pellet selection.

I have the same situation that you have when I got my Gamo Big Cat. Using the included Gamo 3-9X40 non AO scope I was pretty happy with it for the first 500 pellets then my groupings starts to open up. I was breaking in my Big Cat at that time since I already ordered a Leapers 3-9X50 AO scope with R/G illuminated mildot reticles from Pyramidair. When the scope arrived and sighted in there was a very big difference on the tightness of the groupings. I guess for one thing is that an AO scope can focus pretty good even at 5 yards and still be able to use the max 9X magnification you can get from it. Having also a mildot guide on your scope is a plus for indoor and outdoor targets as well. I think the original Gamo scope has an issue on keeping a true zero that is why after some time your shots seems to open up. With the Leapers scope my groupings can only go as far as 1/2" at 10 yards indoors (bench rest) that's why I believe it's not much a problem of the airgun itself but more of my hold. With the old Gamo scope I would just sometimes scratch my head thinking "how in the world did I get a full 1" flyer on this particular shot?". By the way I also changed the included one-piece Gamo scope mount to an ACCUSHOT one piece high mount so I can have some nice clearance for the 50mm objective lens on my Leapers scope.

The GRT-III trigger helped a lot on my shot consistency. Without that predictable and light trigger I don't think I can achieve those under 1/2" groupings always at 10 yards.

I'm actually planning to change the piston spring on my Big Cat. I hope Gene or CDT can help me know the exact replacement spring that I need to order from James Maccari so my Big Cat can perform better.

Oh, and one more thing - I noticed that the my Big Cat is very hold sensitive. I found out after installing the heavy leapers scope that the best way to shoot my airgun is to place my left open palm just right after the trigger guard. Holding the gun at the exact C.O.G. location tends to put my P.O.I. upward and to the right.

Hope this helps and Good Luck on your Big Cat!

Speedturtle

[airiscool]

Mine had what I assume was hold sensitivity too.  At least it seemed to shoot better if I placed my fist under the pad just in front of the trigger guard.

I'm not fond of that type hold because of the shorter stock hold length can also make it prone to left/right pivoting.  

Since I've put on a better scope and one of  Mr Tuna's trigger's, I re-tired a relaxed fore stock hold. I'm glad to see that the  shot groups got even better. Maybe it wasn't hold sensitvity so much as being able to pivot on fist combined with the original  Gamo trigger that pulled like it was a cinder block ?

Anyway,  she's now consistantly doing 3/8 to 1/4 inch c to c groups at 10 yards (indoors) with  Super Domes.  This is  REALY getting fun !!!!!!

Next is to get outside and  see how she does at longer yardage.

Paul.

[Evileyes]

Hey Boz.
I got a new Big Cat from Big 5 the type that comes with a crummy gamo scope and the 2 piece mounts. It shot O.K. out of the box but nothing great. I gotta tell ya... Try different pellets and put a good scope and mount on it. It will make a difference. You can pick up a good one piece mount online and buy a nice adjustable objective scope for around 60 to 70 bucks. I've bought 2 Centerpoint 4-16x40 scopes at Walmart for 70 bucks and 1 AR22 airgun scope for 50 bucks and they are great. As far as pellets go, you gotta try lots of different kinds. My Big Cat does'nt like CPHP's but loves Beeman Crow Magnums. Also try heavier pellets that almost always increases accuracy.
Hope this helps. Good luck.

[Walt]

Boz
I also joined the new Big Cat crowd recently and I did a little work to it and up graded the scope and I like some of the other replies say, find the pellet that your Cat likes, when you find the one that's usually the cure. I think my Big Cat is my most pellet picky gun. Mine likes Wolverines from Sportsman's Warehouse the best. The rest I've tried just seem to be good break in rounds. Good luck.
W

[Boz]

Thanks for all the replies guys, I'm sure allot of it boils down to pellet selection.  I will eventually replace the scope with a nice Leapers, the set up I'm using already has a pretty nice 1 peice mount.

I also discovered the screws in my stock to be SLIGHTLY loose, so I snugged em up.  I ordered 4 tins of JSB Exacts, if these aren't any more accurate ill shoot em through to break in the gun and continue the search.

I definatley need the GRT Trigger, this thing pulls like a mack truck right now....

The CPHP's are giving me about 2 inch grouping at 30 yards, with some wild fliers hitting well outside 3 inches. The gun itself is a real hammer, being one of the more poweful air rifles I've fired.  I think I'm going to add in the Venturi Gas Spring when the internals wear or fail.


Anyone use a BC with the Venturi Gas Spring installed? I would like to hear your experiance with it.

[bodiej]

Everyone seems to have given you the book on things.  I didn't see a reply to your barrel cleaning question.  I've read somewhere here that CPHPs are an extra-dirty pellet that will foul or "season" quicker than most.  I almost gave up on my Titan before I was told to try them.  Now it shoots like I always wanted it to.  However, I might need to do some barrel care earlier than most.  If it looks gritty inside (esp 4 inches or so from the breech), then I'd say clean it - using any of the advised methods on this site.  Even running some clean patches through could help alot (so I've read)...

[dnttech]

Boz, when you get those JSB Exacts, I think you're gonna find they shoot very well.  Of the 3 air rifles in my collection which I've shot, all 3 love the JSB's best.  I use other pellets which can come close to the groups I get with JSB, but for overall consistency, they seem to work best for my rifles.

[Boz]

Got my JSB's in and they seem to be shooting great, however Im noticing a pattern to my gun.  As I shoot 2 pellets will just about make the same hole, then the next 2 I shoot hit about 1/2 inch higher but hit just about the same hole.  Repeat that same pattern after every 2 shots.

I think this POS  Gamo scope is creeping on me, not holding true zero.  That'll be next thing replaced.  If I shoot 2 shots, then 5 clicks down, 2 shots again, 5 clicks down I can keep it pretty tight.  Think my pellet selection is solved, now for a scope.