GTA
General Discussion To Gateway To Airguns => Gamo Gate => : RCnMo May 21, 2008, 02:45:38 AM
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Well, after about 4000 rounds, my spring finally broke in my .177 CFX. Anybody know a good replacement mainspring and while I'm at it, does anyone know which aftermarket seal would be the best choice? I may go back to stock, just because this rifle has been my favorite shooter. It never missed it's target unless I was closing my eyes.
Thanks.
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Well Ralph,
It looks like you received good service from your Gamo spring, but if you want something else, Jim Maccari makes a great spring: http://www.airguns.citymax.com/catalog/item/251488/43410.htm (http://www.airguns.citymax.com/catalog/item/251488/43410.htm)! He also carries seals and lube kits ..
Remember !!!! if you do this yourself, always use a Spring Compressor !!!! The eye you save, may be your own !!!
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if you want i have a stock spring for a cfx that has maybe 700 rounds through it that you can have if you want it
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This is what I like about this forum. Kind folks willing to give info and even parts. Yel01z06, I sent you a PM and I thank you for your kindness. I took the CFX apart today and didn't even need my compressor. The spring had broken about 3 coils up and intertwined with the remaining spring. The spring had also started a stress crack about 8 coils down inside the piston. I assume this all happened at once because I was chronygraphing pellets today and the last three shots just took a nose dive (860fps down to 760 fps) I didn't notice any crunching or abnormalities during cocking or firing until it wouldn't lock at the bottom of the stroke. I figured I would eventually bust a spring. This is a good excuse to do a little tune up. The innards all look suprisingly good. I deburred everything and cleaned enough grease out of this thing to lube a merry-go-round. The breech seal looks good and the O-ring on the rotating breech looks good too. I figure I will go ahead and replace it while it's out. I think I am going with a JM seal, but I'm stuck on springs. The old one looks like a B-19 or Quest spring and JM makes a drop in for that or I could stick with stock which has been fantastic.
Thanks again
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...according to JM. There are kits you can buy that have a spring, new guide, etc.
Another option is to use Crosman Quest parts. Spring C1K77-010 and tophat C1K77-005 will fit into the CFX, and I frequently find that the Crosman spring (which is a tighter fit on the Gamo guide) reduces spring twang. You can also use the C1K77-002 piston seal.
In my experience the Crosman parts make about the same power as the original Gamo parts. I think you can get a spring, seal, and tophat for about $15 shipped.
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Thanks, I wish I'd thought to measure the spring in my 1000x and count the coils. I e-mailed JM today and he had me measure my old spring and stock guide. He is sending me an E3650, which is one more coil, .002" larger diameter wire and should fit the stock guide quite a bit tighter than the original. The E3650, I believe is a .515" I.D. spring and my stock spring was a .534" I.D. The stock guide is .483" dia. Therefore, it should be about .0095" tighter on the stock guide and the O.D. should only be about .015" smaller on the diameter than stock. Hopefully it works as well or better than stock. Even with the sloppy fit to the guide, this rifle had suprisingly little twang and no perceived torque. I also ordered a Tesla seal. Believe it or not, the old seal looks remarkable. Only slightly discolored, no pits or scuffs. and still measured .995" which is tight in the cylinder. My cylinder mics out at .9845" giving the old seal a true .005"+ fit. I believe the parts in this rifle would have lasted indefinitely if it weren't for the spring. I'm already having withdrawls from my CFX.
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Remember that with a thicker wire and one more coil the spring won't compress down to the same length, if the gun won't cock that could be the reason.
The additional coil tends to make the spring softer, while the thicker wire tends to make the spring stiffer. The net result (in this case) seems to be a slight increase in stiffness (on the order of 3-4%)
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If it won't cock, I guess I will have to machine another spring guide. I don't think I will chew on the factory guide, because with it's stock setup, it was a sweet shooter. Worse case, I will put a stock spring back in it and have my old baby back. Now I have two guns that need guides. I reckon I'd better order a stick of Delryn..
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the e3650 is a good spring. i have one in a bigcat right now. the stock guide with shrink tube fits perfect and tight. will cock fine too. its a very powerful spring.
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The E-3650 is indeed a good spring and a pretty good fit and drop-in if machining a fitted guide and tophat is not an option. It's also far superior to the Crosman spring in quality, composition and fit. Same with the seal. The Chinese replacement seal composition is the same and is no where near the quality of a good aftermarket seal such as the Apex or others. I would never replace Chinese parts in a gun with more Chinese parts unless there were no other option available including replacement seals and springs. And when it comes to those guns, I just don't tune them because I know that I'll not provide the customer with the results that I would expect. I've never understood why one or possibly two people continually suggest or even present it as an option other than perhaps cost but in my opinion, but that's not a good reason if it's worth the difference in improvement to the individual.
The Chinese seals that are used are a very inferior seal and not the least bit forgiving. As a parachute designed seal they are almost useless because of the material composition and because they are so hard, do not allow for even expansion. Because they are so hard, even under the high pressure they are subjected to, they still do not seal anywhere near as efficiently as a seal made of better materials. Also, they do not lube and provide equal distribution as a good seal does and are quite often the cause of excessive dieseling and/or detonation, are usually the cause of wide velocity deviation and inaccuracy and when that happens, hot spots are created on the seal making the seal even harder in those area thus perpetuating the problem even more. This is even more of a problem if the incorrect lubes are used.
Of course there is no comparison to my TurboTune and that’s not to be suggested but I have used some of the E-3650's for those that didn't want or could not forego the additional expense of the TurboTune. And the difference in the wire diameter and extra coil will have no impact in not being able to cock as long as the tophat height has not been increased. Gene and I did a number of side by side springs and guides fit checks and with all thing considered, it is a good alternative for those that home tune their gun. As a drop in, it doesn't resolve or make the gun perfect but sure is an improvement over the Crosman or Chinese parts hand down.
If you want to follow another’s suggestions and consider using what I would call inferior parts for tuning a gun rather than just "replacing a broken part", that's fine. But if you are going through the labors and "expense" of tuning your gun for improvement for accuracy, consistency, a better shooting cycle and planning on keeping it for awhile then to me it sure makes sense to at least put quality parts in it so that you can attain your expected results given your capabilities and access to tools. And it costs very little more to do it right. Just don’t let someone mislead you into using parts that will not accomplish for you what you expect. You may see some improvement but it’s not going to be what it’s capable of. If you want to simply replace a broken Chinese spring with another Chinese spring….fine… but if you are tuning your gun, give it some additional thought and make it really worth the effort.
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Thanks for everybody's response.