Case prep Q with Dillon Trimmer & Resize/Decap Die

[Panther308]

Have the Dillon 1200 trimmer mounted on the Dillon trim die.

What I would like to know is, Should I trim the cases first, and then decap/resize them in my standard resize/decap die, or does it matter what order they are in?

The reason I am asking is because it may potentially help save me a lot of work.

The resize/decap die sized the case, and then expands the mouth of the case with the expander.

To my knowledge, the Dillon trim die only fully resizes the case.

So am I correct in assuming that if I deprime/resize my case in the resize/decap die, then take it to the Dillon trim die (to trim it), then I would have to go back and run it again through the regular resizing/decap die process again? My assumption is based on expectation that the resizing/decap die expands the mouth of case slightly, but the Dillon trim die then squeezes it back down during the trim process, resulting in the need to run the case again through the resize/decap die process to expand the mouth of the case again.
Am I thinking this incorrectly?
Maybe it does not make a difference, but I would like to know for sure.

Thank you in advance for your help.

 

[Panther308]

Re: Case prep Q with Dillon Trimmer & Resize/Decap Die

ttt

 

[ChadTRG42]

Re: Case prep Q with Dillon Trimmer & Resize/Decap Die

You need to trim it AFTER you size it, not before. So you would want to size/deprime, trim, powder, etc. What round do you need to trip and expand the mouth on? If it's a bottle necked rifle round, then no mouth expansion is needed, and might need to be trimmed. If it's a pistol round (9mm, 40, etc), then no trim would be needed.

 

[Panther308]

Re: Case prep Q with Dillon Trimmer & Resize/Decap Die

it is the .308 round.
The reason I am asking is because someone was telling me that if I resize first, then trim (using the dillon trim die), then the expanded mouth of the case will need to be expanded again (since the Dillon trim die would compress it slightly).
Then, another person told me it does not matter. I want to do whatever the right way is.

From your answer, is it safe to assume the dillon trim die has the exact same dimensions as the dimensions of a case, after it is resized and mouth is expanded with the sizing/depriming full length die?




<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ChadTRG42</div><div class="ubbcode-body">You need to trim it AFTER you size it, not before. So you would want to size/deprime, trim, powder, etc. What round do you need to trip and expand the mouth on? If it's a bottle necked rifle round, then no mouth expansion is needed, and might need to be trimmed. If it's a pistol round (9mm, 40, etc), then no trim would be needed. </div></div>

 

[ChadTRG42]

Re: Case prep Q with Dillon Trimmer & Resize/Decap Die

I am not 100% familiar with the Dillon tripm die, but it should not alter the case, other than trimming it shorter. I trim it, but I would not expand the mouth on a 308 case. it is not needed.

 

[mgoodrich]

Re: Case prep Q with Dillon Trimmer & Resize/Decap Die

When I used this system on my 220 swift brass, I had to trim first and then run it through the decap die with plenty of lub in the neck, since the decapper had to expand mouth out on its way in.

If I tried the opposite way, you could see bullet was now expanding the neck out, since the trim die in my case was compressing the neck more than the regular sizing die.

I have since stopped using this system since I was working the brass so much I would lose quite a bit of it.

Started to neck size only on the swift brass, and found that I did not have to trim it so often.

 

[Panther308]

Re: Case prep Q with Dillon Trimmer & Resize/Decap Die

just got off the phone with a Dillon Precision person (as I was typing this). he said the following:

- decap and resize the brass
- trim (with Dillon trim die and trimmer) and swage it if needed
- run through the resizing die again (this time, the process will open up the case neck to proper size).

This is because the regular sizing die/decap process squeezes the brass to proper dimensions, and then as the case leaves the sizing die, the decapper opens up the mouth to proper dimensions.
If you do trimming after that, then the Dillon trim die will again compress the mouth of the case a bit. So to me, looks like the trim die is a standard die without the decap/expander capability.

So all this means to me is that it is a much better process to do the trimming first (which will size the brass down only), then run it through the normal full size die process (this time will be much easier since case is already resized, and only thing needed is to expand the neck with the expander. Then, the case would be loaded as usual.

How does that sound, or do I have anything backwards here?