Case Trimming

[WSM MAGNUM]

In my 30 years of reloading I have never trimmed any of my cases. I did not shoot bottle neck cases that much to where they exceeded the max. length. I just bought a case trimmer and I want to trim all my cases in all the calibers I have. It is good practice to even trim straight wall cases if one wants good consistancy on bullet seating and crimping for all types of cases.
I am going to start with the .45 ACP cases. All manuals give the max. case length at .898". Now for the trim length, different manuals give different trim lengths. Sierra says to trim at .893". RCBS says to trim at .888".
I feel that .888" would be too short as .45 cases head space at the case mouth on .45 semi-auto`s. Should`nt the case alway`s be at .898"? I`m going to trim at .893" or .890".
I wonder what the trim length is from other reloading manuals? I think there should be only one given trim length for .45`s in semi-auto`s because the cases headspace on the mouth of the case.
How long do you trim yours?

[The Lovemaster]

It's been my experience that the "trim to" length is listed the same in all my manuals.

I have never had to, nor do I ever plan to trim straight walled handgun cases. I only trim my rifle cases.

[Ozzieman]

++ to The Lovemaster.
I have never sized 45/70 ether.
As much 45 ACP and 9mm that I reload, if I did have to trim, I think I would stop shooting.

[WSM MAGNUM]

Let me rephrase my question here. Why do different reloading manuals list different trim to length measurements? Notice I said trim to length, not the maximum case length. I am thinking that .45 ACP cases should always be .898
because of the headspace. If you trim a .45 ACP case shorter than that would`nt there be too much headspace. Or if it gets over .898", you would also have problems.
I`m not asking if you think you should trim or not. Like I said, I have never trimmed cases either, but I think it is good practice to do it once in awhile if you want consistancy with your cases. Especially if you want even crimps on every round. Straight wall or not.