is it 300 yards from any public roadway?
and in what areas?
and considering sound travel?

There are no laws restricting the use of firearms on private property. 

I think the biggest issue would be noise.

Within city limits?

I think it depends on how freedom-loving your neighbors are.  You could have the best house, on the best lot in the best neighborhood, but all it takes is one bad neighbor to ruin it.  That being said my uncle in TX has 22 acres and he shoots on his property, but then again that's TX.  You'd probably need at least that size in Hawaii, depending of course on noise........ noise is the number one problem I would think.

I think the biggest issue would be noise.

I think noise is done by a sustained level, is it not?  Like xx DB continue or something over a specific period of time?

One of the other fellas posted in a thread about a building a new range the chart from an Army Regulation that the Army uses when planing ranges to establish the SDZ Surface Danger Zone. Let me see if I can find it for you. Unless your parcel is up against the mountain or down in a gulch you'd have to have so far after the targets down range and a lateral area cleared and these distances increase as the calibers being fired increase. I have near 8 acres but I have houses on most sides of my property, could I shoot here safely probably but I would have to do a lot of work to make it safe.

Within city limits?

Isn't the whole island within city limits?

No laws under unlawful discharge of a firearm,
But it can or may fall under reckless endangerment .

is it 300 yards from any public roadway?
and in what areas?
and considering sound travel?

Topic has been discussed before and little has changed... https://2ahawaii.com/index.php?topic=237.0 AND https://2ahawaii.com/index.php?topic=1864.0

One of the other fellas posted in a thread about a building a new range the chart from an Army Regulation that the Army uses when planing ranges to establish the SDZ Surface Danger Zone. Let me see if I can find it for you. Unless your parcel is up against the mountain or down in a gulch you'd have to have so far after the targets down range and a lateral area cleared and these distances increase as the calibers being fired increase. I have near 8 acres but I have houses on most sides of my property, could I shoot here safely probably but I would have to do a lot of work to make it safe.

DA PAM 385–63 (SDZ data is in Chapter 4).

DLNR says 50 yards

Thanks for the interesting replies   more thoughts on the subject are surely welcome

Pretty much what was said earlier, gulch or side of a mountain, or a mile or two of land downrange and space to the sides.  Not really feasable unless except maybe if you own a lot of agricultural land or ranch.

The original question is "legally."  And as I've said before, there are no laws against shooting on private land anywhere in Hawaii.  You own one square foot?  You can shoot there.

Reckless endangerment only applies if the bullet leaves your property. 

Noise ordinances are pretty easy to work around.

Now, can your neighbors call and complain?  Sure they can.  Can the police get creative in finding things to charge you with?  Probably.  Is it safe to shoot in your tiny patch of paradise?  That depends on all sorts of things.  But it is legal?  Yes.  Yes, it is legal.

Hmm. Wife and I are looking at 10 acres in the South Point  area. Thanks for this info.