first off, what does it mean if the primers become flat after firing? i noticed the edge around the outside of the cup is flush with the primer pocket wall, and not rounded off anymore. a few out of the 50 were still round, but most became flat. is this bad? also, i have a set of lee pacesetter dies for my .270 and was wondering if the sizing die is a full length sizer or just neck sizer. the reason i ask is because i was thinking a full length sizing die might erase the posibilty of them being more consistent the second time around because of the fire forming process the first time. will a full length sizer die decrease the fireforming benefit?

To the best of my knowledge the Lee pacesetter is a three die set with a crimp die a seater die and a full length die.
http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=684845
If you are looking to "neck Size" and you like the Lee stuff you need one of these.
http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=472118
Flattened primers can be a bad thing (high pressure) but, not always. How are you setting up you sizing die? What are the specifics of your 270 loads with flat primers? Brass, powder type and weight, bullet type and weight and primer.

Research partial full length resizing. Try it. If you still get flat primers, back off your loads a bit and see what effect it has on them.

Flat primers are like tea leaves, not really worth much unless things are really bad, and then there are usually other sources of info available that will be more useful in making your determination.

FWIW, almost every factory load I every shoot in a rifle has a greatly flattened primer due to the short headspace factory ammo is made with to allow it to chamber in most any rifle. If the primer is removed from the case and looks like a mushroom, and/or a new primer fits very loose (or falls out) worry. Worry a lot. Otherwise, just be careful.

It helps if you tell us what bullet/powder/primer combo you are using too.

oh, well, my loads are pretty light. I was using 130 and 150gr. bullets, 130's were hornady interlock's and the 150's were ballistic tips. ranging from 53.5 to 55.5 grains of H4831 powder. it was a light load, so i don't think it was pressure, i could be wrong though...

Hodgdon has a MAX load of 55.7gr of H4831 for the 150 in the 270 Win. If you were shooting 55.5gr with the 150's you were at published MAX. Did you have flat primers with the 130's as well? 55.5 is well below max for the 130's.
Keep your FL dies. In most cases you will need to FL size your brass after several handloads using the Neck Sizing die.

Oh, ok. i forgot till just now that i have not shot the 50 or the 55.5gr. loads yet, only went up to 54.5. i still have the other 2 loads left. i didn't notice them until a while ago, and i have already tumbled them and they aren't in order anymore, so there's no way for me to tell which ones were which. i'll pay attention to that next time.