Author Topic: bigcat velocity  (Read 7391 times)

Offline larspawn

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Re: bigcat velocity
« Reply #15 on: May 29, 2009, 11:53:41 AM »
I personally smear Crosman Pellgun Oil on all my breech seals.  Kind of like a preventative lip balm treatment.  All of my breakbarrel seals seem to hold up like new.  Okay I realize that doesn't help you now...

The Gamos are notorious for breech seal tears.  They are also buggers to replace.  Taking them out is the easy part but the first time can be deceiving because it isn't just an o-ring sitting there.  It goes in much deeper.  Just stick them with a sharp object like a knife or thumbtack point and pry out.  The trick will be seating a new one.  They tend to tear up if you don't get them seated deep enough.  A smooth wooden end of a popscile stick or the end to a wooden kitchen spoon is a good tool to have on hand.  Then lube with Pellgun oil and keep your fingers crossed when you close the breech for the first time.  If you did it right it will seat a bit further and you will be good to go.  If not you have 3 more chances to perfect your technique.  

I order a tube of Pellgun every now and then from Pyramydair cause I shoot lots of C02 and I liberally use it on the seals/rings.  Just don't overdo it and don't put any into the transfer port or barrel.  Just lightly coat the seal.  I don't recall ever seeing Pellgun at Walmart but I know they sell at Meijers if you have those in your neck of the woods.  Don't use any petroleum based product on your seals.  If you can't find Pellgun oil to to Home Depot and get a little tub of Plumbers Silicone Grease.

Good luck.

P.S.  I find that at 10-15 meters the cheap Daisy Precision Max wadcutters are hard to beat and actually I get better results than Gamo Match, RWS Hobbys or Meisterkulgns wadcutters.  But my BC happens to like Crosman Premier Hollow Point domes from Walmart the best at ranges >15/20 yards.  They shoot better than CPLs and CPHs.  I think the perfect pellet is 7.9 dome type in any 1000 fps (advertised) rifle and I've tried pretty much all the different pellets.
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Guns:  One less than too many...

Offline xschug3

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Re: bigcat velocity
« Reply #16 on: May 29, 2009, 05:57:49 PM »
Larspawn, thanks a ton for the detailed tips. I'm actually looking forward to recieving the seals now that I have detailed instructions and I know what I'm in for.
Crosman Premier Hollow Points are a pellet that I have not tried. So far I have the best results with JSB exacts, but I think most guns like them. My BC also like Predators. I have heard alot of people having good luck with CPHP's in their Big Cats so I will pick up a tin of those soon. Thanks for the tip on the grease from Home Depot. I will likely go get some of that because I expect to recieve my breach seals tomorrow and I'd like to begin the project asap. I hope this takes care of my velocity problem. Thanks again for your help, I really appreciate it. I will keep you posted on how the job turns out.
Gamo Big Cat 1200 w/GRTIII and Centerpoint 16x40
Walther Force 1000
B-3
Daisy Powerline 880 from \'95

Offline larspawn

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Re: bigcat velocity
« Reply #17 on: May 29, 2009, 11:05:25 PM »
If you can't find Pellgun oil I understand it is basically the same thing as ATF (automatic transmission fluid) and you get a quart for the price of a little tube of Pellgun.  It even looks similar with a redish tint.  You can also try that route.  Again, just make sure you never put petroleum based products on any o-ring or seal.
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Guns:  One less than too many...

Offline xschug3

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Re: bigcat velocity
« Reply #18 on: May 30, 2009, 07:17:10 AM »
Larspawn,

That's probably what I'll use then since I have ATF right here on hand. Thanks for the info. I'll let you know how the replacement goes.
Gamo Big Cat 1200 w/GRTIII and Centerpoint 16x40
Walther Force 1000
B-3
Daisy Powerline 880 from \'95

Offline xschug3

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Re: bigcat velocity
« Reply #19 on: June 01, 2009, 02:56:26 PM »
Update on breach seal replacement:

I recieved the packet of breach seals today from GAMO. Larspawn, I took your advice on the pushpin method for removing the old seal and it was out in 10 seconds. Surprisingly very easy. I went out to the garage and got the automatic transmission fluid and lightly lubed the new seal. It slipped in place fairly easy once I used the edge of a wooden spoon. I realized how beat up my old seal was once I had that new one in there. I dabbed the excess ATF off the new seal, popped the barrel back in place and voila, it fit perfectly

On the very first shot I clearly noticed a difference in the way the gun shot. I don't have a chrony but could tell the cans I was shooting were being penetrated with more force. It seemed the holes that were being made were cleaner cut too. I also noticed a little bit stronger recoil (kick) after replacing the seal. I guess this makes sense.

Anyway, the procedure only took about 5 minutes at most and it turned out to be what I needed I think for my velocity issue. Between the barrel clean and breach seal replacement I think my velocity is back up to where it originally was. Larspawn, thanks for all your help and advice. It was very useful.

Thanks guys.
Gamo Big Cat 1200 w/GRTIII and Centerpoint 16x40
Walther Force 1000
B-3
Daisy Powerline 880 from \'95

Offline larspawn

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Re: bigcat velocity
« Reply #20 on: June 01, 2009, 10:47:36 PM »
Happy to help and glad you are back in business!  I know some people badmouth the BC but I love mine.  Guess it is luck of the draw but mine shoots the lights out.  Way lighter, easier to load and about as accurate as my TX200!

Have fun and see you back here sometime.

Andy Wong aka larspawn
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Guns:  One less than too many...