Check your load book. It should have the trim to length. I use the lee case trimmer, cheap, easy and it removes all doubt since the gauge is the correct trim to length. I am currently using the .223 and 7mm gauge and have had no problems.
Also, your weapon may not like this load, it is just the load that my dads AR liked bests as far as accuracy goes and no stress to the spent casing.
Be sure to check several books for load data, you never know, I could be some gun hating lib that would love nothing more than to see you blow up your weapon! I use the Horndy, Lyman and lee manuals. The Lee manual seems to be a bit on the hot side and i like the Lyman manual the best but it does not always have the powder I am using at the time. You can always check the powder Manufacturers web site as well.