trimming with Wilson trimmer ?

[dansig]

I just got my wilson trimmer from Sinclair, I trimmed a few cases and they were all different lenght after trimming, not by much but still a difference. about .002-.005

then I took a close look at the trimmer and found nothing wrong, everything was tight and straight.

so I took a look at the cases, Lapua 6mm BR Norma fired 5x, first look showed nothing wrong but I knew there had to be something.. so I took a case and put it in the trimmer reversed, took a few turns on the base and took a closer look, the base didn't trim the whole circle but only on one side, I put it back in the trimmer but turned it 180° so the side that got trimmed would be on the other side and took a few more turns.. the case still got trimmed on the same side but now it came half way around so I took a few more turns and the base got clean full circle, then I turned it over and trimmed the neck, did that to a fwe cases and measured them, they were all spot on the same size.

so the problem is that the base of the cases is not uniform after it's been fired.

now for the questions..

should I trim the base ? it's not much, barely .001 but enough to make the base uniform and parallel to the neck.

does anyone else trim the base before trimming the neck ?

is .005 difference enough to affect accuracy when shooting ?

 

[Forum Boss]

Have you removed the spent primer before trimming?

Your situation sound pretty odd. I think a Wilson trimmer, with the correct case holder, should be able to trim lengths within .002 (two thousandths) base to case-moth case OAL.

 

[Zia Hunter]

There is an indent on the threaded rod that controls cutter depth to alleviate the problem of protruding primers or debris affecting the trim length. Make sure the case is properly seated in the case holder and that it is held firmly in place backed up against the threaded rod. Also, make sure you are finishing the cut. My Wilson consistently trims cases to .001 or less. I use a cordless screwdriver attached to the cutter head and can trim cases quickly.

 

[timeout]

Try reading this post: http://forum.accurateshooter.com/index.php?topic=3783770.0 There are several good tips to using the Wilson trimmer. The one by Bozo699 on top of page two may help you. If anyone can get to the bottom of things, Wayne usually can. I don't have a Wilson trimmer yet. If you give up on yours, perhaps we can make a deal!

 

[amlevin]

If I read the post correctly, it seems like you bolt face may not be square with the chamber/bore centerline.

This causes the case head to take a "cant" when fired. When measuring the trimmed case try rotating it in the caliper so the anvil contacts the case head in different areas. See if your measurement's change.