small dry fruit often means too little water during fruit development.

Where do you live?

and what are your irrigation practices? (How often; how long; what system -- drip, trickle, sprinkler, hand-held hose?

I have a Blenheim Apricot (supposedly needs 400-500 chill hours and we get less than 120 here). It's also only been in the ground less than 3 years. (it's on standard rootstock too)

But it has two things going for it—full sun and I made sure it was well watered. We got a nice crop of 11 apricots this year.

Well actually, the full sun may have even been detrimental, since in this climate the warm temperatures during the Winter days subtract from chill accumulation, and the stone fruit needs all the chill it can get here. So I'd have to chalk it all up to the water. I turn the hose on extremely low (almost dripping) and give the water plenty of time to gradually into the soil (maybe 20 minutes to an hour). The water is able to soak deep down this way. 2 times a week during the summer (the summers here are very hot and dry).

A lot depends on your climate. You need to make sure your trees are getting what they need, and compensate for the particular climatic factors where you live.