Lol...you must be retired,without a wife, and never watch TV,or have a lawn to mow, or have kids or grandkids living within 100km of you...
I'm kidding of course! I wish I had the spare time to devote to such a thrifty enterprise.
I don't think the OP is trying to be thrifty. Maybe he is?
I think he's just curious and wants to see for himself what the results of his "burning questions" peaking his curiosity will be.
He's repeating at home experiments many of us have done over the years, learning from it, etc.
I've picked up thousands of snow cuddled rounds out of the target berms at our range. Mostly to clean up the lead. It's amazing how quickly it adds up.
We don't see a lot of unfired rounds, but about a decade back, I found a half dozen bricks of CIL 22lr in the bin. A few boxes had been take out of each and the duds were still in the little yellow plastic trays with black inserts to separate the rounds.
I guess the person couldn't be bothered to take them home.
I tried a few in my rifle and had the same results.
I took them home for the bullets, which pulled very easily, and ended up with appx a pound of small flake powder, that was yellow and gray. Much different than that in the OP's photo.
The lead bullets could have been reloaded and I even did reload some in my 22 Hornet.
They didn't shoot well, the loads were too hot and caused them to strip on the rifling, rather than spin. I had to reduce the loads to appx the same velocities generated by the original 22lr rounds to get good accuracy. Why bother?
I ended up melting them all down into .500 round balls for my Lyman 50 cal Plains Rifle. A bit hard but still workable with a thicker patch.
The powder in all of them was fine. The priming compound in the rims had deteriorated.
I filled the 22 Hornet case with as much of the powder as I could compress and maintain OAL to fit in the magazine with 40 grain, flat base bullets. I believe it was around 10.5 grains.
Velocities were OK, close to factory offerings. Accuracy was borderline acceptable out to 100yds on bunnies.
I wouldn't do it again unless I was desperate.
As for pistol bullets. I've picked up a lot of those as well.
The OP is right on when he states they load well, feed well, and are quite accurate—even the cast lead bullets.
Do you save any money? I guess that depends on how you value things.
I've picked up and shot a few thousand fmj 30 cal and 31 cal bullets in days gone by, and they worked OK. Not nearly as accurate as their new counterparts but fine for fouling shots and a few other things, or just shooting branches floating by on the creek, to practice on moving targets.