Please don't take this the wrong way or personally... just an observation
Wolff offers three spring grades for Charter - light, medium and heavy. But you said "extra heavy". I'm not one to split hairs, but I am one to try to decipher a person's feeling and attitude about a situation. I have observed that when someone, anyone, uses superlatives, it more often than not reveals underlying sentiments that are unresolved. Here's what I'm saying, suggesting even: Before you give up, give Charter (or any company that made some less than perfect product) a chance. If we were talking TVs, you might say this Sony is the biggest waste I've ever made, although many others have experienced otherwise. You might say, I sent it in, and it still doesn't work. Ok, well, maybe there's more than they realize, or maybe there's something situational, or maybe they just goofed. But, that old bugger, Mr. Frustration comes-a-calling and well, no good comes from that at all. Another case in point. My GF wanted a new vehicle. A smallish SUV. She had a Jeep that was beginning to need more than casual care, so... her livelihood depended on her wells....a new vehicle. We looked. She liked Ford - mostly because my Ford has over 300k miles, and runs pretty well yet at 20+ years old. She got a Ford. She has it two weeks - check engine comes on. I tell her, run it in to the dealer PRONTO... even though I pull the codes and they were nonsense as to any real issue. Dealer does their diagnostic, no problem, and resets the codes (which I could have done, buy ya know... gotta let the dealer see it). A month later. Check engine light. I pull the codes, take a picture of the code reader so its date stamped. She brings it in. No problem, reset codes. Two weeks later... same thing. But this time, the service manager calls her, she has him call me. He says, Ford released a firmware fix for errant check engine that occurs under conditions XYZ and they flashed the brain, ok to pick up, may run a little rough for first 15-20 miles as brain relearns that particular engine. Never did run rough. That was four years ago, and all is well with almost 80k on the odo. You see, some folks may have said, screw that, I'm selling this lump of offal. Some people may have called a lawyer, or tried a "lemon law" return. The thing is - a real company, known for good things, will stand behind their product, if you let them do so, but... an amazing thing.... you have to meet 'em in the middle and work with 'em to make that happen.
That's the end of my rant. Nothing personal, really, it applies to everyone who's thrown in the towel, when what they really needed to do was continue to dry off a little and get out of the stream of dripping water. In all my years, I know of only one company that could not fix a firearm, and admitted they had issues. That was HK who replaced my own P9s with a P7M13. Wish I still had that P7. Oh well. At least they stood behind the CUSTOMER and did the right thing. Charter has been known to replace guns "just because", so give 'em a go.