I am new to case trimming and recently bought a Forster original case trimmer. I set out to trim 20 .243 cases. First, I measured all of the cases and found that the shortest one was 2.042 inches. So I inserted that case into the collet and set the adjustment screw on the cutter shaft (according to the instructions) so that the shaft stopped at the length of that shortest case. I then proceeded to trim the other 19 cases to what I thought would be the 2.042 length. Well, about half of them did end up that length. But some ended up at 2.040, some at 2.035, and some at 2.039.
What am I doing wrong? The cases are set evenly and firmly into the collet. With the Forster, you do have to tighten down the case holder so that the collet will compress around the base of the case. Is this where the problem lies?
Any help would be greatly appreciated.

HnTxs:

You must tighten the collet consistently or you'll get the variations that you are experiencing. There is slop in the collet if you don't snug it down.

Still, variations of .001" - .003" are to be expected. No big deal; just make sure you trim to approximately .010" under maximum specified case length.

Rick, thanks for the reply. I am trying to be consistent in the amount that I tighten down the case holder and I am getting it good and snug each time. It was just that the variations in length of the cases was similar to what they were before I trimmed them (just all a little shorter now). So, it did not seem like I did any good by trimming them. I thought the point of the trimming was to get them all exactly the same length to aid in consistency.
Most of the cases (after having been fired) were already shorter (before any trimming) than the case length listed in my reloading manual. What is the minimum case length for a .243?

Length spec for 243 is 2.045" -.020". So it would be 2.025"

Roger: Thank you for the tip on the Sinclair tool. I am going to look into that today for sure!
Case trimmer situation solution - sell your Forster and buy a Wilson! PROBLEMS SOLVED! Do it today and save yourself the misery I went through for many years until I sold all my trimmers and went with the Wilson system!
Hold into the wind
VarmintGuy

Is there a primer in the cases that you're trimming - if so, could this cause variation (if they're not seated deep enough or if they've been fired and have "swelled" any)? I don't know how the Forster collets are designed - may not make a difference.

[ 01-16-2003, 05:43: Message edited by: TXRam ]

Hn Txs,
I switched to the Forester about three years ago after using a CH trimmer for a lot of years. Your problem seems to be the same one I ran into, cases being shorter than the trimmer was set for.
I found two possible causes for this. The first cause was due to case trimmings getting onto the seating face of the collet. The second was strickly me. The directions say to move the neck pilot into the neck and then hold the case snug against the collet as it is tightened. I cured the first one pretty quickly by looking at the seating face of the collet before doing another case. This reduced the extent of the shortages. It took me awhile to read the directions and follow them. That cured the shortages. Another Me caused problem I found was that some of the cases were longer than they were supposed to be. I was lazy and stopped turning the cutter too soon. The fact that the cutter felt as though it were through cutting didn't mean it was.

The Sinclair tool that rogerinneb mentioned is called a case length gage and cost just over five dollars. I have a bunch of them. I like my case necks as long as possible to insure correct alignment of the bullet to the axis of the bore. That's why my .30-06 and .308 Win. cases are headstamped .270 Win. I swear by these gages. One suggestion I would make though, is rather than full length resiz e the case your going to modify to use with cage, trim a fire formed case first and then just bump the remaning neck against the neck sizing portion of your sizing die. Just enough to hold a bullet with little pressure. This will make it easier to move the gage into the case neck as well as to remove it from the case. Good luck.

Hey HnTxs, Welcome aboard!

You are experiencing the same thing everyone goes through the first time they begin using on of the Lathe style trimmers. And I agree with the guys which said it will get better the more you use the tool.

The bad news is Lee makes a small, inexpensive, hand-held Case Trimmer that works even better. Plus, it allows you to carry a group of cases into the Living Room and trim them while watching Catherine Bell on JAG!

The Foster is as fine a Lathe Style trimmer as is made, but there is a learning curve.

Thanks everyone for the replies. I will definitely get a case length gauge. The cases are unprimered when I am trimming them. And I made sure that there were not any trimmings in the collet before I inserted the case. I also measured each of the cases before and after trimming with a caliper gauge. I guess, like everything else, it is just going to take practice! Thanks again everyone. I found a lot of good information here.