Pruning looks easy on paper, but it is anything but! No berries are not smaller. Some like the convenience of just knocking them to the ground. Also some have had bad luck with small summer crops. I think the small crop could be a cultivar issue. Some cultivars producing a decent summer crop, others not such much. Also could be an environmental issue. Too hot for a good summer crop etc.
It's up to you, what works for you. A summer crop also can block the new primocanes from growing well giving you a small fall crop. I guess this may happen with summer bearer's too! Always having both floro and primocanes.
I myself prune for a summer crop only removing the upper third of fall bearing primocanes, the part that fruited.
They will grow numerous fruit bearing laterals in the spring, amazing to watch!

Either way it is best to trim canes in late winter or early spring before bud break. Right now your canes are full of energy that is slowly moving to the roots (sugars, starches etc). If you cut them, you remove the energy source. Having said that, they still will be fine. You can do it now if you must. It will not kill them.

I myself have found the summer crop to be actually larger than the fall crop, so I can't bear to lose the berries. This year I am removing some canes because they are blocking another cultivar. So I'm doing both! My raspberry bed is a jungle. Many primocanes will be removed because it is too crowded. Good air circulation allows existing canes to dry better, and thus less likely to become diseased.
I grow over 15 cultivars in 2 beds. Both summer and everbearing.

This post was edited by Drew51 on Wed, Sep 25, 13 at 17:41

Thanks Drew. I will wait till winter for those. I also have some Triple Crown and Navaho Blackberries that grew exceptionally well this year. I pinched the growing tips and the laterals got crazy long. How long should I let the laterals get before pinching the tips on those? Or am I not supposed to pinch the lateral tips? Thanks again.

Some leave the laterals grow forever. Leave them at least 18 inches. Most guides I have read say to trim to 18 inches. I'm leaving some long, some at 18 inches, see what happens... Do it with the raspberry pruning late winter , you don't want to promote further growth at this time. Pinching now may stimulate weak growth that will be damaged in the winter. Keep us updated! I'm still learning with blackberries myself. I did cut them back when actively growing this summer, but now so late in the year, I'll wait to trim any additional canes. They are still growing but at this point we need them to stop and harden off. My summer bearing raspberries have already started that process, and stopped growing. They are much like blackberries. Bigger than the fall bearers too, but not as big as blackberry canes. I did trim some summer bearing raspberry canes at 7 feet! Wow!

Some of my laterals are 3' long I will not cut them to 18 now but I can do it in the winter or spring or just let them go at the length they are?

" Some of my laterals are 3' long I will not cut them to 18 now but I can do it in the winter or spring or just let them go at the length they are?"

I know some growers here do let them go, but it is against conventional wisdom. I really don't have the experience to know what is best. I plan on leaving some go, and cutting others to see what happens. Mine are at least that long too!
I guess one plant has limits, cutting them to 18 inches may allow the plant to produce fewer, but higher quality berries? Not sure? Plus the laterals may grow more in the spring? I know they do on raspberries. If we leave them at 3 ft they may grow to 6 ft! I guess we will find out :)

According to this article from WVU, it does make larger berries to pinch them. Note is says to cut canes to the ground after fruiting! I guess chance of disease is too great to leave for winter with blackberries.

Here is a link that might be useful: Pruning blackberries