Case trimming- how many times?

[milboltnut]

I haven't used mine, and I had it for along time. The guy who told me about it said it works great.

 

[brant89]

I shoot basic every day brass. Only stuff I trim is my 223 and 308 range brass the first time. Only because of the crimp. Then I can't remember how many firings even if I ever trim it again. Never had an issue because brass was too long. I'm not a bench rear champion just need to kill the animal first shot.

I think the bigger concern with not trimming is pressure spikes and bullet release if the case neck gets jammed into the throat. I don't think anyone should expect to see improved accuracy by trimming, but it's certainly possible to have a very bad day if a case gets too long.

 

[Reelamin]

I think the bigger concern with not trimming is pressure spikes and bullet release if the case neck gets jammed into the throat. I don't think anyone should expect to see improved accuracy by trimming, but it's certainly possible to have a very bad day if a case gets too long.

That is what is so great about this forum. People get to share their experience information and beliefs freely unless they get disrespectful.

I'm a free spirit hippie is the nicest way to describe myself!!

 

[Axl]

all are good remarks but one has to start somewhere : good brass is good brass- bad brass is and will remain bad brass so all the neck turning and or reaming may help some . When I turn I ONLY do the HIGH SPOTS., now. Trim , again how good was / is the brass and if pushing it- well you know the answer to that one.
I'll check my brass prior to loading each and every time- but not trim till it grows to a point ( depending on the gun if TARGET-HUNTING etc )

This might be a record reresection- this thread is 17 years old tomorrow!!

 

[RUFFIAN R - NY]

in same boat as Reelamine picked two up one in 223 and other 308 have large count of both brass's don't see a difference yet . Besides i don't shoot as often with 223 or the m-14 . Been hitting the 6.5 CM and playing with the 6mm XC II .

 

[Mikecr]

How many times you have to trim a case has little if any bearning on case life. What you want to be looking for are not how many times I've trimmed the case, but that shinney pressure ring (streach mark) forward of the web, loose primer pockets, splits anywhere on the case, yes even the neck. Now you will find cases with 35 and 40 deg sholders don't grow vary much, I've never had to trim these cases more than twice before they had given up the ghoast anyway.

It can be a rule of thumb, once you consider WHY you're trimming to begin with and WHERE that brass came from..
For instance, if you're causing excess headspace with excess FL sizing to cause frequent trimming, then you're likely thinning brass at lower bodies. After all, what you trim away worked it's way up from somewhere.

Personally, I nearly never have to trim, and it's as rare that I have to retire any cases.
I don't choose cartridges that force it (something like a 30-06), and I don't FL size.
So if I found that I did have to trim, something is wrong. My load is wrong, my die is a mismatch, etc.

 

[JMHNL]

Being relatively new to reloading, I made the mistake of trimming a bunch of ADG brass to min. SAMMI trim spec after the first firing....which was nearly .005 in some cases. I think it changed my neck tension for sure, and I also wonder if this gap between the end of the case and the lands is a place where a carbon ring can form. Maybe I'm overthinking it, who knows, but I wish I would have just kept it longer and trimmed after the 3rd or 4th firing.

 

[Lefty38-55]

RCBS 'X' sizing dies, properly adjusted ... trim only once

 

[milboltnut]

It can be a rule of thumb, once you consider WHY you're trimming to begin with and WHERE that brass came from..
For instance, if you're causing excess headspace with excess FL sizing to cause frequent trimming, then you're likely thinning brass at lower bodies. After all, what you trim away worked it's way up from somewhere.

Personally, I nearly never have to trim, and it's as rare that I have to retire any cases.
I don't choose cartridges that force it (something like a 30-06), and I don't FL size.
So if I found that I did have to trim, something is wrong. My load is wrong, my die is a mismatch, etc.

what makes you think if you that anyone who loads this cartridge that it would force to trim ? Maybe what you should say is if you bump shoulders it doesn't cause brass to flow to be trimmed. You're way out of the ball park friend.

 

[Mikecr]

Being relatively new to reloading, I made the mistake of trimming a bunch of ADG brass to min. SAMMI trim spec after the first firing....which was nearly .005 in some cases. I think it changed my neck tension for sure, and I also wonder if this gap between the end of the case and the lands is a place where a carbon ring can form. Maybe I'm overthinking it, who knows, but I wish I would have just kept it longer and trimmed after the 3rd or 4th firing.

Your thinking is right.
It's best to measure chamber end so that you can set desired chamber end clearance as necks close on it.

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Carbon does build up in excess clearance, and you get sooting down necks, sometimes all the way down shoulders. This is gas blowing back interfering with case sealing.
A lot of people just trim to book, or to shortest in a batch. Neither is right. A good clearance is 10thou or less, provided you're watching and managing this.

 

[Kansaswoodguy]

I get about 8-10 firings on my 6.5 creedmoor before retiring that batch of brass I honestly could care less on number of trimmings they have on them. 223 I'm really not even sure how many firings I get usually on them. 223 get a neck split and they get retired because of that. I will say only bumping the shoulder back .003" leads to longer brass life.

 

[milboltnut]

It can be a rule of thumb, once you consider WHY you're trimming to begin with and WHERE that brass came from..
For instance, if you're causing excess headspace with excess FL sizing to cause frequent trimming, then you're likely thinning brass at lower bodies. After all, what you trim away worked it's way up from somewhere.

Personally, I nearly never have to trim, and it's as rare that I have to retire any cases.
I don't choose cartridges that force it (something like a 30-06), and I don't FL size.
So if I found that I did have to trim, something is wrong. My load is wrong my die is a mismatch etc.

I don't choose cartridges that force it (something like a 30-06), and I don't FL size.
So if I found that I did have to trim, something is wrong. My load is wrong my die is a mismatch etc.

Mike you really need to go back to the basics. I found out that I have a carbon ring by the leade of the chamber. I trimmed back to max trim length and bumped .002 and have a bit of resistance unlike our conversation on Pm's of me needing .004 bump back and you totally trashed the 06 about shoulder design and that it's an antiquated cartridge, etc etc....

If trimming is needed, it's because over full length sizing is excessive. Once I found out about partial FL sizing or bumping the shoulder back trimming is non existent.

 

[Varmint Hunter]

Just to repeat some good advice that I read on LRH:

Close a case in the chamber and use a bore scope, inserted from the muzzle, to determine if or when a case needs trimming.

IMO there is no need to trim back .010" if you know exactly what length your chamber will allow. Who knows, maybe you have .010" clearance, or more, even when the brass is at "trim length" according to the manuals.

Just something to think about.

 

[milboltnut]

Just to repeat some good advice that I read on LRH:

Close a case in the chamber and use a bore scope, inserted from the muzzle, to determine if or when a case needs trimming???????

IMO there is no need to trim back .010" if you know exactly what length your chamber will allow. Who knows, maybe you have .010" clearance, or more, even when the brass is at "trim length" according to the manuals.

Just something to think about.

Trim back back from max and it will be fine.