I have been loading / reloading for a few years now but consider myself still pretty new to it. Hence, I am asking this because the kid across the street is just starting, and asked it of me. Well folks, I simply didn't know! He is loading for two rifles; A 270 and a 45/70 as well as a 45ACP. The 270 I can help him with. But the straight walls..? Well here is the situation, and question. He bought new brass, all Remington in the bag. Good so far, but..? It's all way shorter than minimum published length. It is also a bit off square at the mouth. Should he run it through his dies, and then do a minimum trim to square? Even if it is already "short?" (He already ran the 45/70 through the sizer.) Would the 45 ACP be treated any differently? Then he asked me about de-burring. Just how much is enough? I told him to just smooth off any burrs, and not to make it a "sharp" shoulder. Was I correct? I realize that is subjective however if there is a definitive answer that would be great. This kid is doing liquid division at fifteen... Hmm... Stopped posting to go and check something. All of my brass, the new stuff, is way short, all of it. Remington, Winchester... 270 Win, 35 Whelan, 357 Mag, 9mm, 10 Auto, 45 ACP, 357 Mag, and 45 Colt! Perhaps this isn't all that a silly question! Any help would be greatly appreciated!