Help with lense choice for new guy.

Having recently bought a K110D (an upgrade from a panasonic lumix FZ7). The lenses that came with it are the standard package 55-200 Sigma DC and Pentax 18-55 DA and i have also bought a Sigma 70-300 DG and a 1.5x AF converter.
I intend to take wildlife (bird shots), Is the Sigma 70-300 a true 300mm or is it 450mm to take account of the 1.5 cropping on the camera, I am assuming it is 300mm because of the DG suffix.
If that is the case I am thinking of getting a 70-300mm Pka manual and a 2x Pka converter to take advantage of the 1.5 cropping. Is this a good idea ? Also will the 1.5 AF converter work okay with a Pka lense (obviously not the AF function). I want to stick to Pka rather than Pk because all the manual stuff is a bit daunting at the moment. Any help or comments would be most appreciated.

The Sigma is a 300mm lens whether it's used on a DSLR or a film SLR, however due to the cropping effect of the smaller APS-C DSLR sensor size it's effectively the same as a 450mm lens would have been with 35mm film. The same is true of your 55-200 - at the 200mm end on a DSLR it's equivalent to what a 300mm lens would have given you on a film SLR. The fact that's a digital only lens isn't relevant.

BTW the Sigma 70-300's all work on both film or DSLR bodies.

I don't really understand the question about a 70-300 Pka lens though as that's exactly the same focal length as your existing 70-300 Sigma DG.

The 1.5x convertor should work in MF with an MF lens.

BTW I've tried a 2x TC with my own Sigma 70-300 and AF did function up to about the 250mm setting in decent lighting conditions. It was quite slow however and I've no idea what the results would be like optically.

Thanks for your quick reply you have answered my question perfectly. What i was hoping that buy buying a 300mm manual focus lense ie: without the DG (Digital) suffix i would gain some extra milimeters due to the cropping effect on the camera but that is not the case and i certainly can't afford the sigma 170-400mm at around 450 pounds.