Originally posted by cleaverx
RobG, try to use quick shift focus. When I first started to use my 55-300mm WR I didn't use quick shift focus that much. Later on I appreciated what this feature has to offer.
I start using it almost like a semi-hybrid manual/AF. It made a world of difference. Every time I picked the object to shoot I would manually thru quick shift focus focused on the object and then
let the AF takes over either in AF-S or AF-C...this way the hunting you experiencing will be minimized since you are helping AF to hone on the object. I am not sure if Canon or Nikon lenses even have quick shift focus.
We are blessed that Pentax using this in most new lenses.
Try to use it all the time and it will became natural. Don't give up on that DA *300mm f/4 it is a superb class lens (I wish I have one

)
I have the DA 55-300 (previous to WR) and it is a pretty good looking image producer in good light. In addition to quick shift, I use the back AF button with the half press AF turned off. I find that quickly grabbing a contrasty subject, such as a branch or reed, at the same distance using the back AF button and then pointing at the subject works well.
As for MF, I do use the M 400/5.6 quite a bit. The extra reach is terrific. I also use it with the AFA 1.7x with surprisingly decent results. (See the kids in the surf in my gallery and the oyster catchers). They were taken with the K10. With the K-3, I find the extra light on sensor with higher ISO much more useful. The ability to crop down to the equivalent of K10 pixel density is making the AFA 1.7x used much more often.
I don't have a huge budget. Actually, I don't even have a small budget. I have to make do until I can come up with a few extra dollars watching drunks in the local drunk tank.