CFX.22 broken spring after 750 rounds

A couple of weeks ago I sent my CFX to Gamo for repair of a broken mainspring. The rifle was bought new from Pyramid Air in Aug. of '07 so was still under warranty. 700 rounds were mostly a mix of RWS Superdomes and Beeman Silver Arrows, with maybe 50  Kodiaks making up the balance. The gun was inadvertantly fired once with the breech open and no pellet loaded. When new the rifle had plenty of power, but with occasional erratic velocities. Over time the power slowly diminished and became more unpredictable, until in May of this year these problems had become so pronounced I knew I'd have to return the gun to Gamo.

 I realize there are several factors that could have contributed to the spring failure, including shooting the heavier Kodiaks, to the one dryfiring incident, to the possibility of a defective spring in the gun when it left the factory, but I'd like to hear some opinions from members of this forum.  

[tjk]

Forget heavy pellets like the kodiaks and silver arrows,...they're spring killers. If you insist on using a heavy pellet, I wouldn't use anything heavier than the cro-mags. You really don't need that heavy a pellet. That's just my opinion. I doubt the spring was defective, but no factory springs are as high a quality and strength as a custom spring installed by a tuner. Dry firing usually doesn't mess with the spring as much as it does the seal. Once the seal is ruinned, it will have to be replaced. Just try not to dry-fire at all if you can help it. I've done a few times myself, and it never gives one that sense of security in knowing you may have broken something. Arggggggg?!?!?!? One last thing, God forbid it if you put anything like "chamber oil" down the exhaust port of the chamber. That stuff is junk, it will detonate, and you will end up with a broken spring. Trust me on that. Hope you can get it tuned soon, and start back to shooting ASAP!!! tjk

I've not used any kind of lubricant on or in the rifle, just wiped it down with a silicone cloth after each use. I never had a problem with detonation or dieseling, either.

 I'm disappointed to hear that the silver arrows are too heavy to use...they shoot well in my gun and really pack a punch. (and they're only 2.1 grains over CDT's recommended maximum for a .22 springer.)

[Big_Bill]

This is just my opinion Doug,

If you talk to CDT, he may be able to install a heavier spring into your CFX. that way you may be able to shoot the heavies !

But if you continue to use Gamo springs, you will have to use settle for pellets in the lighter weight range.I believe that the new Gamo springs are not as good as they used to be, my Gamo 890 is about 10 years old, and has had 1000's of pellets through it, and it is just lately that I hear a spring twang when firing. I think it may be time for some of CDT's magic !

Now I'm not even sure that such a spring exists ! just a thought.

Bill

[tjk]

sorry D, I assumed you were shooting 17 caliber,..but I think the same rule applies to 22's but on a bigger scale. Glad to here you haven't  lubed anything on the gun. Call Charlie and see what he says. Super nice fella too! tjk

Thanks for the comments, tjk and Big Bill.  Granted that it was the heavy pellets that killed the spring, isn't spring failure at only 750 rounds unusually early?

[tjk]

I can't answer that, but jumping from different pellets (25 heavies then 25 lighter pellet, and so forth) might have something to do with the spring failing, or some kind of spring/memory fatigue and finally it just snapped. I'm only spit-ballin' here, but that could have something to do with it. The more I hear this saying, "find one type of pellet that works in the gun and stick with it", the more sense it makes. Bet there's more than a few reasons this saying has been stood the test of time. Or you may find two pellet types that excell in a particular gun. Maybe a round diabolo and a wad-cutter, etc. As an emample, my 0035 shoots c.destroyers pretty consistant. It's 7.9 grains, so I feel I'm staying in the "safe weight" zone. Being that it shoots in thehigh 500's to lower 600's, I also found the 7.1 S-bears to shoot very good in it with a little added velocity, and the weight isn't too light to resemble dryfiring with say non-lead pellets (hyper-velocity types). I avoid them like the plague!!!!!! Kkeep experimenting with different pellets, until you find one or two that work well for you and the rifle. Just stay in the safe weight zone for spiringers and you'll do just fine. Good Luck, Thomas

[LPC]

been there and done that. what a terrible feeling. kinda like gettin heartbrokened. i did the same. my cfx22 had already had over 1000 rounds of 14gr-17gr through it and oneday i decided to use kodiak extra heavies. it was on a cold night in the sacrament valley last november. i was shooting cans in the backyard while sipping on a cold beer and after a few shots between 15th and 20th shot, i felt the rifle go plunk as it fired off a round that arched out of the barrel onto the lawn short of the cans range. so i go to cock it and it sounded like a bed with a bad spring in it. the thing was that it was tuned and had a maccari spring in it. so the long story short, them kodiak heavies can kill even the best springs. they'er better for a pcp airgun it seems not a springer.

i've found that my rifle likes the rws super h-points 14.2's and the superpoints 14.5's. give them a try next time.

LPC, your posting was what I needed to confirm that the Kodiaks were the culprit. Too bad, though, because I really got a bang (and a broken spring!) out of shooting those heavy mothers. Also too bad that the airgun manufacturers don't warn against using pellets that are too heavy for the gun. I'm a fun shooter, mostly steel soup cans at 100' to 150'. The Silver Arrows would blast thru two large cans at 125'. I'm wondering, though, if at  17.1 grains they aren't a good idea either. I tried the Superpoint 14.5s right about the time my spring started getting bad, and they went every which way but into the target. Maybe they'll perform better with a new spring. I should be getting the CFX back from Gamo this coming week. I'll probably give the Super H points a try too. Thanks for the helpful advice.