The best (IMHO!! ) trimmer is also one of the oldest. Take a look at the L.E. WILSON trimmer. This is a very simple design but is absolutely dead on accurate. So much so, that dedicated Bench rest shooters use them all the time. What is unique about the system is that the shell is not held by the head of the case as in most other trimmers. The WILSON trimmer holds cases by the CASE BODY via a shell holder. It's kind of like a short section of a barrel chamber that is cut short enough that about 3/8" of both ends of the case sticks out. The down side is that it is probably a little slower than other trimmers and you need seperate holder for each specific shell. However, many shells will work in the same holder, i.e., .270 Win, .280 REM, 25-06, 30-05, 35 Whelen, or 22-250, 250 Savage, 300 Savage. You get the idea. The shell holders are very cheap, about $6.00 at Midway. What makes the trimmer so accurate is that the shell is held in position based on the headspace of the case. Other trimmers hold by the case head which CAN be a few thousands out of square depending on the bolt face of the gun.
As far as too short goes... .010 short is just about perfect. TOO long and your chamber pressures can climb dramatically.
If you just want blastin' ammo, any other trimmers will work perfectly. If you want super accuracy and consistantcy. Look at the WILSON. Also, the WILSON has primer pocket reamers and inside neck reamers that work in conjunction with the case trimmer. It's a sooper system!
