I have a question for all you long time reloaders out there. I am new to reloading and several of you have already helped with some previous questions to which I can't thank you enough! I have another question for everyone, I have searched throughout books and this forum but could not find an answer to my question. Its in regards to case length. I am starting on reloading .223 for an AR. I have looked up in the Hornady book that the COL is 2.25" using the 75gr BTHP bullets. However, I am curious as to what I should trim the brass too. I picked up a box of Hornady 75gr BTHP bullets to break in the barrel until all my reloading stuff gets here. I measured the case on those bullets, but when I go to trim mine, I can only get the case to within +/- .005". Is this acceptable? How do I get to an exact measurement? I'm kind of anal about that, but don't know if I'm just over doing it or what? I am using a forster original trimmer and it took me ruining several cases by cutting them too short before I got to within that measurement. How can I pre-measure that distance without ruining more cases in the future? I know I'll have to change the case length when I start in on my .308 so how do I go between the 2 without ruining more cases until I get within the proper length? The price, and more importantly, the availability of brass sucks so I am trying to conserve what I do have. Thanks again for all the help and advice!!!