i also have heritage and caroline. are you sure that the problem is water? last year was a very wet one here. this year is quite dry and though I am regularly checking the ground for moisture- it seems as mine are drying up as well. difficult to tell if the issue is not something else. my carolines are in part sun- many scorched looking leaves. some berries are small and dry, others have white druplets.
what are the chances you could be giving them too much water?

I'm a zone 6a here and my Carolines are unaffected by 95+ degree temps. I only water maybe 1-2 times per week. They are in darn near full sun 8+ hours.

I don't think it's a case of too much water, I just am at a loss given both varieties are subjected to the same conditions. (Nature & my imposed)

This month we've officially had 6 days over a hundred degrees (102, 104, 106, 106, 103, & 104 and more unofficially observed) plus 18 days in the high 90's (11 of those being 97, 98, or 99 degree days)

My home digital as well as my truck showed 107 & 108 degree days during this time as well. So we've really been burning up (like a lot of the country).

The only variable that I think may be having an impact is that one end of the row of Caroline is within 10 feet of a metal building which could be putting off heat, but I would not think that would impact the far end of the row....

I just didn't know if the plants would be better off if I cut them down now rather than allow them to struggle on, or if that would do more harm than good.

Been a tough summer on everything.

Well, it's a bummer here too for my Carolines as the leaves are pretty much all burned up and the fruit production is shot. On the other hand, on the canes with the leaves that died earliest, new shoots have been emerging down low, I've begun pruning off the cane tops above the new shoots to get them light and see what happens with them. My hope is that the new growth will bear fruit though I doubt it, at least the new growth should help the plants get some stored energy for next year.
BTW, we have been in the low 100s to high 90s for about 2 months straight with no rain, very unusual. I'm thinking about putting up %10-20 shade cloth over the bed next Summer as Caroline does seem to have a druplet problem with our 90s heat during picking time.
One way to avoid some heat problems is to plant something like Royalty which bears much earlier, before the heat of Summer. My primocanes on Royalty are doing just fine in this god-awful heat, kinda wish the Caroline bed had planted to Royalty now.

Good luck everybody!

Royalty sounds like a winner for hot climes (Though it would mean I couldn't be as lazy and just mow 'em off like I do with ever-bearing varieties).

I'm a little hesitant to go to chopping away just yet, so I repositioned a support wire/cable on the trellis and hung up some sheets to shield them from the sun. Probably too little too late.

Never thought I'd say it but I'm ready for winter!!!