To trim post or pre neck-sizing?

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rugbydave

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I've always trimmed my brass as a last step, pretty much, other than chamfering/deburring. I'll run the case through a body die, then neck die, clean the primer pocket and de-burr the primer flash hole, trim and chamfer the case neck, then sort brass as needing to be trimmed or not (whatever got trimmed would get re-chamfered and de-burred). I got to thinking the other day that perhaps the neck tension wouldn't be uniform between the cases that get trimmed vs those that do not? I could trim before neck sizing but that makes triaging the brass kind of a pita in that the dimple often left in the spent primer kinda screws with measuring case length. Thoughts?
 
This is from a previous post of mine. I use the Lee Power trim kit. I rigged the trimmer with metal washers for consistency. The plastic adjustment thing it comes with is junk. Trim, chamfer, deburr in one step. I got mine set to Max SAAMI, i run all my cases through it, if they're too long they get trimmed, if they're under max they only get chamfered and deburred. It's quicker to run them all than to start measuring which ones need trimming and which ones don't. Beautiful thing is when you set the cutter to Max it will repeat in both sleeves, no adjustment necessary.

I do this after the neck sizing operation as sizing will influence total length the most. If you're not turning the necks and using bushing dies I don't think it matters much to neck tension if you trim after sizing. However If I was turning necks and using bushing dies, which is my next step in reloading really, I would likely trim first.

I find the only major downside to trimming before tumbling is if I'm not careful with the wet tumbling I'll end up with case mouth peening. If it's bad I'll have to deburr and chamfer again.
 
Thanks. I trim with a Forster trimmer with the drill adapter but chamfering and de-burring have to be done separately. I also chamfer and de-burr before neck sizing as I read that you wanted that done so that the case moved smoothly in the die? I get that bumping the shoulder in a body die will cause the case to lengthen (where else will the brass go? haha) but I didn't think that collet neck sizing would affect the length of the casing at all? I don't bother tumbling again after trimming anymore since I'm body sizing and then neck sizing, there's never any case lube inside the casing and there a quick wipedown gets rid of the wax on the exterior.
 
In the end I think that as long as your process is always the same you'll get good results that will repeat from one case to another. My current process is more geared towards speed and efficiency than absolute accuracy. I could add extra steps to my process like neck turning, bushing dies, sorting cases by chamber volume, etc... but I think I've attained a good balance between overall reloading speed and accuracy. To get significantly better results I would have to invest much more time in my reloading process, definitely less return on time invested.
 
rugbydave said:
Thanks. I trim with a Forster trimmer with the drill adapter but chamfering and de-burring have to be done separately.
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Unrelated to your original question, but the Forster 3-in-1 cutter head (trims, deburs & chamfers all in one step) for $90'ish, was some of the best money I've spent on reloading gear. It saves SO much time (and cramping hands) from doing the chamfering/deburring manually...
 
Qball-16 said:
Unrelated to your original question, but the Forster 3-in-1 cutter head (trims, deburs & chamfers all in one step) for $90'ish, was some of the best money I've spent on reloading gear. It saves SO much time (and cramping hands) from doing the chamfering/deburring manually...
Click to expand...

Will that forster 3 in 1 tool fit other trimmers other than the Forster trimmer like the RCBS Power trim 2?
 
Qball-16 said:
Unrelated to your original question, but the Forster 3-in-1 cutter head (trims, deburs & chamfers all in one step) for $90'ish, was some of the best money I've spent on reloading gear. It saves SO much time (and cramping hands) from doing the chamfering/deburring manually...
Click to expand...

Thanks! I didn't even know that existed. Looks like I'll have to order one!
 
Qball-16 said:
Unrelated to your original question, but the Forster 3-in-1 cutter head (trims, deburs & chamfers all in one step) for $90'ish, was some of the best money I've spent on reloading gear. It saves SO much time (and cramping hands) from doing the chamfering/deburring manually...
Click to expand...

+1 I bought one this week...just gave it a try. Fool proof and a real time saver. I highly recommend.
 
With neck sizing only you should not have to trim until the shoulder is bumped back, assuming the die is set up correctly. Usually get 10-12 loads before shoulder needs to be bumped.
 
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