Look here for a prior discussion:
I agree with Damon! The spring that is in the automatic nozzles produce a pretty stream, even at low pressures, which could lead an inexperienced pipeman to get a false sense that they are getting the proper gallonage. We use a break apart, constant gallonage nozzle with a fog tip and a 15/16 inch smooth bore. I prefer the smooth bore myself as it can be used at a lower pressure with better penetration than the fog.
I am glad this discussion came up, we have the TFT Automatic Fog Standard/Low pressure with breakaway tips to the 15/16 smooth bore on our 1 3/4"
The standard gives a nice stream no matter the gallonage.
The low pressure stream increases the gallonage by 50 GPM or more at the same pressure with less reach. I think the main idea of the low pressure fog is for high rise type scenarios when your pressure sucks and you still want at least 100 GPM flowing, which as I said, has less reach.
The 15/16 Smooth Bore of course gives you 185 GPM at 50 psi NP. The only problem is, the TFT 15/16 Break away smooth bore does not feel like a normal smooth bore. It is not an ideal smooth bore and does not flow like one. The hose is extremely awkward to handle. I have not experienced anything like this before except with these tips. A regular smooth bore tip is much better.
If you want a smooth bore, buy a real smooth bore. Not a breakaway tip.