Help with Trim It II case trimmer set up

[Mac Attack]

I received my Trim It II case trimmer from big bronco a month or 2 ago and finally tried to set it up to trim .223 cases. I set up the trimmer per the supplied instructions and even watched the videos on YouTube. For the life of me I can't figure out how to properly set it up and am looking for advice.

I sized and meassures my untrimmed .223 cases at 1755". The trim length is 1.750". So I installed the 3 way cutter so that it rested against the case making sure the case was centered between the V of the carbide cutter. I then trimmed the case and and measured. The case came in at 1.731". So I reset the 3 way cutter again in hopes of not trimming so much. I trimmed another case and it came in at 1.740. Before I wasted ay other cases I wanted to see advice on how to set it up.

Do I need to set the 3 way trimmer up with a sized and trimmed to proper length case? Do I just turn the micrometer head until I get the proper size I need. The instructions said to turn the head until it stopped turning then tighten the set screw. If I keep this setting I don't have room to go up, only down. Im almost at the point where flat trimming isn't such a bad idea.

Anyways can someone tell me how they set their trimmers up please.

[CSACANNONEER]

Like any other trimmer, back it way out so that it'll still trim too long and start walking it in until you get the length you want.

Another point to remember is that those trimmers use the shoulder for a datum point instead of the inside or outside of the case head. That means that if your brass isn't sized 100% consistently, it will give you different OALs. That would not be the trimmer's fault.

[Enfield47]

I have the original TrimIt and have found that the set screw that locks the micrometer adjuster in place needs to be backed out quite a bit to allow it to fully turn counterclockwise at the initial stage of the setup. If you can't turn the micrometer adjuster any further, back the set screw out another turn to get more adjustment.

I've found that some cases trim more accurately than others and I can't explain why. They have all been full length resized but occasionally I have to make adjustments because some start to trim shorter than the other cases.

CSA makes a good point about how the trim measurement works off the case shoulder. Either way I've never had any issues from it because mine are just plinking rounds and a little variance here and there isn't enough for me to worry about. If I were shooting competition, then it would probably be a different story.

[BigBronco]

Set the three way cutter in a more central position within the cap. Then use the micro adjustment for your minor adjustment. Or bring the cap all the way out to near max length. Loosen the cutter and slide it in until it touches the brass. Then lock it and adjust the cap to get the length you desire. Or call me bud I will hold your hand.