Spring wear

[270windude]

When do you replace a spring? What’s an acceptable amount of damage? I have options and can replace the spring if I choose but will continue to play with things until I make a decision. Just trying to get some knowledgeable people’s advice here. 

So, one of my new E3650 springs sustained some damage. The poorly redesigned breech on the CFR (vs ACCU) allowed me to make quite a big mistake, several times... there have been 2-3 times shortly after install where I managed to fire the gun with the breech still opened. That means the spring was released and slammed into a completely closed wall with the air being forced to escape by unconventional means... presumably through the damaged breech o-ring I had in the gun at the time. The shots all occurred during the same weekend when I was out camping and shooting beyond my mental limit of fatigue. Lesson learned.

The ARH piston seal still looks in top notch shape but the spring looks worse then my older OEM springs I’ve replaced. There’s about 4-6 coils that have far less spacing then the rest. It’s not that pretty but it’s still straight and currently resides in a nice fitting metal spring guide and slick piston sleeve if that matters. 

 

[Yo]

I would replace a spring after noticing it cracked in half. You can tell by the night and day difference when cocking.

 

[JamesD.]

A chronograph will tell you if you're loosing spring expansion power. 
Before you ever think your spring is kaput, make sure your breech seal is correct.

Spring fatigue is going to happen no matter what once an enormous cyclic rate has occurred. There's a lot of exact math & science in a perfect spring gun.

Correct means sized & set in depth to the 0.001" or tighter tolerances.

0.001" too small and you'll have, a bad seal. The piece of tissue paper over breech is one test.

I suggest a depth gauge & feeler gauges.

You stated you weren't sure about buttons or trusting anyone to do them.

Maccari used to sell Delrin stick on ones. Don't know if still available.

The best way is to have someone who does this professionally install them for perfect alignment and smooth shooting. Consistently & as easy on your spring & piston as can be. There's stick on ones. There's guys who can put your piston on a lathe & check the trueness. Is it out of round? They will use a mill and countersink a seat for permanent buttons. They can ring the piston. Just like in a car engine for the best compression. Motorhead is top notch at this. Just look him up or PM me for any of these guys #'s.

I respect your desire to learn. Here's my advice.

Pay John Thomas or Paul Watts to tune & button any old gun you have. Try it out before & after. If their magic amazes you maybe you disassemble & reverse engineer to learn? Maybe you shoot it for years until it needs a new seal, spring, or if you notice any noise upon cocking, possibly new buttons.

I just sold a Walther LGV Master Pro that had a free rotating "ringed" piston.

That gun, to have that done to any springer would cost you around $1000-$1500.00 or more. They aren't made anymore because Walther was loosing money. Very few people will pay what that gun is actually worth. 

Hector Medina specializes in turning RWS 54 power house AG's into fast, short stroke, lighter ringed piston 12ft/lb FT rifles. It's not just the weight of the piston. It's the perfect sizing of the seal. The correct lubes. You know that.

I didn't read anything in your post about the overall length of travel, total swept volume of air. The correct size of transfer point or custom springs from Maccari, OX or a few very high end custom spring makers.

In my personal opinion I believe John Thomas & Paul Watts to be the most advanced innovative spring gun tuners. David Slade is top notch also. I don't believe he'll tune a gun above the factory specs nor button pistons though. His tunes are very good and probably most affordable. 


The only big differences are John Thomas tunes are great if you desire an accurate power tuned rifle that won't tear itself apart. John can tune a gun anyway you want it. I had a few of his and the 18-25ft/lb .22's shot like a tuned 15-16ft/lb TX200
Paul Watts is the man for high end fine guns & shooters who desire super smooth tunes. The fact that he has his own Sunnen honing machine ensures a true symmetrical compression tube, properly sized seal that won't wear unevenly (buttoned piston crucial for this) & the micro fine grooves the Sunnen provides for the correct lubes to settle into for an excellent springer.


Besides these known big name guys. Mike Melick, is also a very very good tuner for the price point & return. Probably $50 less than Slade by what I've read.

On top of that there's so many guys here that know everything there is to know and only tune their own guns. 

 

[270windude]

Thank you for the info. I think I’m going to research what equipment I need and go with the your suggestion of paying for a top tune and reverse engineer eventually. So far I’ve impressed myself with some of my creations given I don’t have a lathe or a mill but nothing’s as nice as proper custom equipment. So far I’ve managed to tame the twang and maintain pretty good accuracy. I’m at the point now where I’m playing with variables in one gun just to see if I can get better accuracy with a given pellet - piston weight (piston plus top hat) vs spring preload. 

I really wish I had the ability to true a piston like you mentioned. Next time I put in an ARH order (thinking soon) I might enquirer about those buttons you mentioned.