Bob Lewis, For the 25 Rem, max length is 2.050" and trim length is 2.043". That doesn't mean you have to trim cases .007" shorter ... it just means cases can't be longer than 2.050".
Overall length depends on the bullet used. Because a 25 Rem is not a SAAMI approved cartridge, there are no COL specs. The best solution is to use a bullet with a cannelure and seat the bullet where the case mouth is centered on the cannelure. The only factory load I could find was a Winchester with a 117gr bullet. It has a COL of 2.58"