fwiw,
I sunk 2" pvc for casing easy enough with a, I forget - 1/2 or 3/4 pvc probe flushing the sand away or digging the hole for the 2", poking it up and down thru the center of that 2", which was coupled with interior couplings. But only 22 feet or so but I'm sure I could have gone deeper easynuff. 50', certainly would think is possible here provided I was non stop fast ...might need to probe the outside if stopped midway to give a bit of wobble more or less to break the sands lateral gripping forces - which happens when you stop for a bit.

Thanks, but I'm thinking 2-inch steel pipe. I guess I don't understand the other stuff mikie is refering to. I'm wondering if I can hand-drive the 2" pipe with a pipe-cylinder sledge.

You couldn't pump enough water with a hand pump to require 2" over 1.25. Driving 1.25 is hard enough as it is, 2" would be murder.

I have driven a 2 inch well caseing with a 100 lb weight with a five foot shaft welded to it. Using pulley and 12’ tripod setup. Works very good

I drove the caseing 42 ft.

Im doing same thing forget about 50 foot I'll be happy with 30 foot getting past 18 foot hardest but it will speed up farther you get don't give up. Mine is our bathing water we need it it's not garden well like yours tough have to do this and have no choice. Pound 2in galvanized pipe with 6ft well point for last 4 years only got 18ft but amazingly do have water every step of the way. Im Next to pond

Usually water won't stay in the pipe but should stay in the point to degree if it doesn't you have to go deeper. All I can suggest is to put old timer hand pump on it and see if you can hand pump water if you can then there is water way down in the point. Best thing to do is don't worry about anything keep pounding that pipe down farther the better. Fyi in some locations it will work and be fine at 12ft but it should definitely be deeper. That's only if you have standing water near by.