I stumbled onto a good number of discarded 30-06 military brass cases & though the majority of them (post-sized) are 2.490 or longer, a couple dozen or so measure between 2.448 & 2.480 With a trim-to length of 2.484, where does one draw the line when it comes to 30-06 brass that is too short — for Garand & 03-A3 purposes? Thank you!
For those rifles, trim any longer than Trim To, and load them all up. If you have any more than 0.100 shorter than it's buddies, call it a fouler and shoot it anyway.
The only time the shortys make a difference is when you have trimmed everything else to the same (longer) lenght, and you seat and crimp in one step. The shortys will not have the same crimp tension. Either don't crimp, or use a collet style to crimp as a separate operation from seating
As stated go ahead and shoot it, brass will stretch, especially if you anneal it , it will be like fire forming to your chamber.
The ones that are 2.480 are no problem but neither are the others. 2.448 is only 4 one hundredth of an inch smaller. 4/10" might bother me but not 4/100".
The wisdom imparted on me by the old timers was that as long as you have one calibers length of the bullet in contact with the case neck the round should have enough neck tension to use. The short ones will lengthen out as they are shot and unless you anneal every time the neck tensions will be all over the map anyway. Only thing that would be a problem would be using the seating die to crimp. Then you need to adjust for each brass length. I find that NOT crimping my rifle ammo increases the accuracy and crimping it degrades accuracy. So there is that to think about. Above discussion before my post has some good points for you to learn from.
I asked this same question a while back... 30-06 as well. and got the same responses. I had my step son helping trim with a manual trimmer. He wasn't paying attention, and the 'stop' collet started to gradually move, making a lot of the brass significantly short. In a nutshell, the responses stated the 30-06 registers off the shoulder, and that being trimmed 'too short' was not a big deal. It's what I was thinking, but wanted to get confirmation. Good Luck