Case Trimming?

bullpup44

bullpup44

New member
I've only been reloading for about a year. I watched my dad a my uncle do it a lot when I was younger though. I can hardly ever remember them trimming their rifle cases. To my knowledge, and by my dad's own admission, he still doesn't trim them very often which brings me to my question. How often do you guys trim your cases. According to my Lyman reloading guide it says, "it is best to trim and entire lot of cases when one or more show the need for trimming." With that in mind I have have a batch of .308 that I have reloaded twice and had to trim both times. Is this normal? Many of my cases, after being full length resized are over the maximum length. I'm getting ready to start a second reload on a batch of .22-250 and I'm going to have to trim those too, again. Do you guys trim cases everytime, or do you trim every other reload? Thanks for reading this long post. Like I said I'm still fairly new to reloading and I'm just trying to make sure I'm doing everything right.
bullpup
 
If your loading hot and full length resizing you should be trimming everytime after you resize.

If your neck sizing you can usually get by trimming every 2nd or 3rd load or less depending on the cartridge.

Regardless of method of resizing I run them all through the trimmer each load for uniformity.
 
I only trim them when needed. Cases will be different as to case stretch. Some will stretch more than others. I can't remember have to trim .308's that often. 250's may be a different story. How much do you trim back from max length?
 
Steve-my book says trim-to lenth 2.005 for .308 so I trim my cases to this length every time. It's the only length that my manual lists. Am I doing something wrong? Is 2.005 just the max case length? Should I trim them a little shorter so that I don't have to trim so much? Thanks again for the help.
bullpup
 
I use the little Lee trimmers, they are a case gauge and trimmer in one tool, fool proof and chucked in a drill fast and simple. They are inexpensive and if you need one for a caliber they don't stock send them two once fired cases and 15 bucks and they will make you one.
 
I ALWAYS trim my cases, before loading...Even new cases
out of the bag.

I use to only trim cases when they were over the max.
case length, partially due to the fact that I HATED
trimming with my Lyman piloted trimmer...What a PITA!
I knew I should trim to uniform length, or at least
suspected I should. So for an experiment, I ran
through two sets of test groups, one set with random case
lengths, under the case length maximum, and one set with
all cases trimmed to same length, near case length minimum.
There was measurable differences in the test groups, and
the all cases trimmed to the same length produced the
smallest groups. I was convinced. At that point I decided
that since I HAD to trim, I may as well get precision
tools. So I purchased the Wilson case trimmer, with the
Sinclair base, with a case holder clamp. Now I LOVE
trimming cases, and they come out squarely cut, and
quite consistent.


Squeeze
 
I trim as needed which for me has never been every reload. Also when you trim the 4th or 5th time that should be the last time you trim that brass, when it needs it again toss the entire batch.
 
I don't have to trim .308s very often but I do not load them very hot. I also neck-size. I like for them to all start off at the same length. I have seen accuracy improvements when a batch was consistent in length.

Full-length re-sizing will 'grow' the length of the case and I would toss them after they have been trimmed 4-5 times. That brass came from the body!

I thought that 2.015 was max and min was 2.005. I don't have my books handy so I would look that up to confirm.
 
You only need to trim when the length exceedes the max length. If your trimming every time, are you lubing inside the case necks? If not, I found that when I started, I no longer had to trim so much.
 
Thanks guys. I went through and re-read my manual last night. I found what I was looking for. The manual was a little unclear as to what the max overall length should be. The way I took it was that cases should never exceed 2.005. After reading it again I found(in only one sentence, I sure wish they would have elaborated on it a little more) where and what the max overall length for a given catrigde is located. Thanks for all the help.
bullpup
 
Part of this answer should revolve around accuracy. And how much accuracy you want depends on you.
But in that vein---
You said the Lyman book said to "do an entire lot at one time"
If you have several rifles and reload as needed, it's hard to exactly match the length of cases trimmed 2 or 5 years ago with cases being done today.
However a big part of reloading is learning to be consistant and uniform. In this light the Lyman book makes sense, if you want the best uniformity for the best accuracy, then shoot all your loads before you trim and so you can trim them all the same. This should reduce the differences that might result from your bullets being released slightly different from cases of differing length.

On the other hand, the devil on my other shoulder says that unless you have a really tight competetion chamber, I doubt it will make a noticeable difference if your over or under by a couple of thousandths of an inch. Besides I get impatient seeing all that bright unload brass around.
 
I tried trimming back .005 from maximum chamber length of custom chambered rifles but didn't notice any difference in accuracy than just trimming all cases to minimum.

Tried the handheld Lee trimmers like Bob mentioned and like them.

I have the case length gauge for several calibers mounted on their own individual cutter. Put the shell holder in a variable speed electric drill...trim, chamfer and polish all in one process. Works great and it's fast.

Pretty hassle free. Your not wasting time readjusting the trimmer for each caliber and you never have to worry about them moving out of adjustment.

Cases shoot just as accurate as using any other trimming method.
 
When I buy a new lot of cases I trim them all to min length then check each time I load then if they get close or over max trim to length I trim again usually if I have to trim a second time it is time to replace them all. But I try to keep cases togeather by lot, usually broken down into fifty piece boxes. (Example) I buy 100 45-70 Cases put them into two 50 round MTM boxes, after measureing and trimming to min case length. I keep track of how many times i have reloaded these boxes, I trim again once, but when they need trimming again usually after ten or fifteen loadings. I discard and replace.

I may use one fifty round box for load development in a chamering I just got. 270 WSM for instance. I am inprocess of building a 243WSSM and am planning on buying a couple hundred cases,I will use 50 to 100 in load development the others since there is a great deal of choices in bullet wt. will be broken up into twenty round boxes instead of fifty.
 
For those who don't trim rifle brass every time, think about this:

The brass is stretching, slowly but surely, some calibers more than others. Nobody's gonna argue that. How do you know each piece of brass is stretching exactly evenly up the case mouth? One side may be longer than the other, and probably is. By trimming every time you load, you're not just making the cases exactly equal in length, you're also squaring off the case mouth. Follow that with chamfering and deburing, and you'll probably see less runout as opposed to never trimming until it's "needed".

* Disclaimer- I can't back any of that up with data, but it makes sense to me.
 


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