Home Forums Reloading Varmint Rifles 223 Brass Too Short ?

I had 50 pieces of once fired 223 brass from my rebarreled 223. I haven't neck sized before, but read the instructions and lubed em up and ran em through. All of them measured 1.710-1.714 after I sized em. This seems way too short. I didn't measure the brass before I sized it.
I'm kinda thinking that the die may not be set properly in the press. The RCBS instructions were the same for FL and Neck Size dies. Anyone else had this trouble? The chamber in the gun is very tight, but I don't think it would make brass shrink.