I bought one of these today, and the 3 way cutter for 223. I can't seem to get it to cut necks straight. I think I'm not getting the case into the collet straight, and I'm seeing it wobble as it cuts. I get perhaps .003" variance when I measure a trimmed case from different directions. Is there a trick to getting this to work well?

This cuts 'em straight and to the same length every time. Never needs to be adjusted...

Is the cutter wobbling? If it's the case wobbling as it's cut, the case is not being held solidly. A pilot is used to hold the mouth of the case. Are you using the correct collet and pilot for your caliber?

I took the thing back today. The cutter seemed to be turning true, but the case was moving a bit. I think I might have had a defective collet. I couldn't get a case in it so it felt well seated.

I'm going to stick with my hornady trimmer and eventually spring for a giraud I think. Thanks for the help guys.

I have a Forster trimmer & I too find it inconsistent.
I've returned to using the Lee cutter & pilots: accurate, repeatable & faster except when trimming to use with RCBS X dies.

Some years ago, Forster put instructions with their lathe type trimmer that stressed the need for lubrication and the areas that need it, in order to assure that the collet was holding the case correctly. For some reason people seem to skip this part or don't believe it. I know 3 people personally who could have posted this Q that were skipping the lube. They all were happy with the machine after they took the time to read the directions and do it right. Another point to be made is that you do NOT tighten the collet all the way until and unless you have the pilot inside the case neck.

Seriously, try Mobil one for this operation.