Ah.....you're in a mining situation.
Sounds pretty much the same sort of thing I have to deal with all the time. The stuff is out there, no doubt about that. Your description of the beach and surf conditions sounds like the real problem area. Soft sand, 3-5 foot surf, and a fairly steep slope into the water makes for tough hunting because that deep soft sand is always getting churned, anything dense getting stirred deep into that sand very quickly. Thousands of people in the water here all week long during the summer but you can hunt all day in the water here and never find anything but lite crap, lite stuff that stirs with the sand instead of the heavy stuff that simply gets sucked straight down. I deal with this every day on my area beaches. But, the stuff is there and there's a lot more of it then you might think. You just have to figure out how and when to get at it. Doesn't do any good to swing the coil over items that are too deep to be detected. A few hours, that's all it takes for items like heavy rings to sink beyond your reach, sometimes not even that long. This is why I say that you're in a mining situation because that's pretty much what it's going to take to allow you to access all of these deeper targets.
Obviously you can't go mining so you have to let the ocean do that for you and believe it or not it's doing it all the time, you just have to locate those places where the mining is a work in progress, and as you've already pointed out the beach is changing all the time so it's always happening somewhere. "Reading the beach" is what this is often called because that's what it requires. In other words, you need to find those places where the sand is being removed. If your beach is anything like mine, and it sounds like it's fairly close to the same, then your beaches have a series of sand bars that run parallel to the coast, troughs between each sand bar. These troughs are filled with deep soft sand, most everything getting lost eventually being dragged or pushed into these troughs and onto their slopes. These troughs are, "loaded with goodies", but due to the deep soft sand they are also deep goodies, most of them too deep to be detected. And so, here they rest until something happens to expose them. Storms, nice when they happen but they just don't happen often enough so you just have to figure out how to access these goodies without them.
Water gets pushed onto the beach and then flows back out, we see it happening every few seconds. What we don't see is how this returning water escapes back to sea. You can't have the same amount of water and force trying to return against an equal volume of water and force trying to come in, so obviously something has to give way, this almost always being the returning flow. As this returning flow is forced out of the way it's often compressed into tighter flows as it snakes it's way back into those troughs before finally escaping into the sea through the breaches or low spots in those sand bars. This is why you will always have some sections of trough that have little current at all, sections that have no means for moving sand out, and there will be other sections that have a great deal of current, or those sections that have more then enough means to move sand out. And as you pointed out already, those breaches and low spots in those sand bars are changing all the time. Whenever you locate areas where these stronger currents exist then that's where the mining is taking place, sand is being removed as the water flushes through them. So let's take a walk into some of these areas to see just how serious the mining operation is.
As we walk past the waterline into the first trough some slopes will be mild tapers while others will be very steep with a noticeable step down, do you know why that is? It's because these milder slopes are created when sand is being slowly dragged back into the water, not a good thing because it's building. On the other hand, these steeper slopes, the ones with that noticeable step down, those sections of trough are being slowly eaten away and the sand is being removed. Pretty cool, hu. It's like having your own little mining crew working for you. And these little current fellas are sloppy workers, leaving thick fragments of shells and all sorts of other "dense and heavy" crap laying about in their wake. A change in the wind or a new breach in a sand bar and those little fellas quickly go to work somewhere else, the area they just left allowed to fill back in and usually very quickly, everything they exposed getting covered again in very short order.
Sometimes the very best mining operations will be far too strong to attempt hunting them, "rips" as they are known. But these areas will settle at some point so you just have to keep an eye on them. Other sections of these troughs will have "long currents" that can run several hundred yards or more, the narrower the section the better the hunting because the slopes of these sections will be cut steeper and deeper, most of the loose sand being flushed out of the entire section of trough. "Seldom will you see another hunter in these troughs" until they have calmed down so much the hunting is super easy and the sand has already started to significantly build again. He who times it right getting the most and best spoils. When one spot is gone go find another, "it does little good to keep swinging that coil over good targets that are too deep to be detected." Sure, you might find a recent drop from time to time but is that enough to satisfy you? If you want to consistently recover those heavier/denser items then you have to consistently hunt where those items can be consistently accessed. Not always easy, not always fun, but it often produces. Hope this helps.
Also, it is fun just learning new detectors so don't give up get tougher & keep your head up don't let it whip ya....
Good Luck
