Measuring factory once fired cases I find they are 2.498 to 2.505 inch. All my books say MAX is 2.494 and trim is 2.484. Is the trim # the minimum length? If I trim all mine at 2.490 will that be good and ten be able to compensate for later stretch to trim again?

I generally trim to minimum. But if you can uniformly trim to the same length that should be alright. I haven't worried as much about it but you can determine the length of the neck in your chamber.

I trim to minimum since a lot of the brass I load has been shot in different rifles and may end up in more than rifle.

Anything at or below 2.494" is sufficient. If you do not resize your cases excessively then a trim to 2.490 will suffice for several firings.

In truth, very few chamber necks are that short and brass can be however long the chamber accommodates. In other words, there is usually some wiggle room. But if you don't know the specific length to the end of the neck cut in a particular chamber always make sure that your brass is of no more than SAAMI maximum length.

Thanks for info. I have (right now, LOL) only 2 rifles I shoot 30-06 in and I keep the bullets separate for both. I do full length size at first then after shooting only neck size since it is going in the same rifle

On trimming,
I've always thought that a good safety practice is to go .01" below SAAMI.

In a high pressure firing the brass and case will flow a bit longer. While I would imagine that a bullet would have left the neck by the time the neck might lengthen to the point of squeezing the bullet, I wouldn't want to do the experimenting myself. So I go .01" back from SAAMI max. It's what the books all say to do, too.

If its hunting rifles i wouldnt bother to separate brass in 3006 it a very common brass just make cartrigdes who fit both rifles.

Trim to 2.484, and then trim again @ 2.494. 30-06 shooters have been using these specs since the early days of the 30-06. These numbers to accommodate, bolt or gas guns of whatever variety. In my case, I full length size and shoot them in whatever rifle, (I have 5 30-06'S), I grab to shoot that day. There are a couple caveat's to this: 1st if the rims get beat up from the auto guns, or if one of the rifles is a little out of headspace. In that case I neck size and keep them separate. I usually get 5-9 loadings with my 30-06 brass.

The 30-06 is not choosey, and will shoot most anything you throw thru it with good results.

Jerry

It's interesting you should bring this up. I recently started to reload 30/06 for a newly acquired 1924 dated Springfield 1903.

All of my fired brass, most of it once fired factory stuff fired from anywhere from last week to 30 years ago, measured 2.499" to 2.512". Remington, Winchester or Federal-they were all long.

And I find case trimming, even with my electric drill attachment on my Lyman Trimmer a very tedious chore. I trimmed them back to 2.480".

Most all loading manuals give minimum and maximum trim length..

Other than file trim dies, lathe type hand trimmers are not particularly accurate, but they get the job done, a few thousands one way or the other doesn't mean much unless your crimping in a crimp grove..

For cases that need to be crimped in a crimp groove the file trim die is the way to go. It simplifies life. Those cases on my bench include the 30-30, 25-35, double rifle calibers otherwise I don't use a crimp.