How much do you personally trim off your cases?

engineer40

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Rockford, MI
If you measure your cases and they need to be trimmed, how much do you usually trim off?



I’m curious of everyone’s opinions on this. Do you trim off quite a lot so maybe you won’t have to trim again after the next reload?



Or do you always try to get the case lengths to equal the same specific length every time you shoot?



Also, how close do you try to get each case length for “match grade” ammo? The hundredths (0.0X0)?



Thanks!
 

Rick Richard

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North Carolina
If you want repeatable accuracy, then all parameters need to be consistent from load to load. Meaning if case length is 'X' measurement and a favorable load is developed and acceptable, then subsequent case lengths should be the same. If there are different case/neck lengths, then projectile to neck tension will vary creating various pressures resulting in some degree of inaccuracy. However in the real world in hunting situations, I doubt most folks could tell the difference between .005 give a or take a couple of thousands.
 

engineer40

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Rockford, MI
Once the brass has been fire-formed, I trim it to SAAMI spec length.

In my reloading manuals it lists a Max SAAMI spec length. Out of curiosity I did some Googleing and found out for my cartridge it said the minimum SAAMI length was 0.020 smaller than the max.

To me, that meant there is a SAAMI range? Not an exact SAAMI spec length?
 

g0rd0

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New germany, NS
I have used the lyman lathe type, I still have it but have not used in years. I have tried the Lee quick trim deluxe, it is ok but I don't like it much. So, I have gone back to using the lee trimmer with a mandrel. It is of the KISS method (keep it simple stupid), but it works!
Each time I shoot I deprime, clean, size, then trim. It works for me and to tell the truth I enjoy the quiet time alone
 

pods8

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Colorado
I use the lee pilot trimmer every time. I chuck the case in a hand held drill, use the pilot trimmer and then use a chamfer/debur tool.
 

gohring3006

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Mar 17, 2014
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Ohio
I order a Lee case length gauge, shell holder and cutter head for every cartridge i reload for, i store them in the die boxes with the dies. There are better ways, but for 5-6 bucks they work.....
 

Mikecr

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Aug 10, 2003
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NC, oceanfront
I measure cartridge base to chamber end with Sinclair's gage.
Then I set the trimmer for -1thou.
With fire forming the necks will pull back more a small bit from this(~5thou), and given that I don't FL size, I haven't needed to repeat trimming.
Seems the trimmed stay within a few thou of each other.
The reason I like close is to mitigate carbon buildup at chamber end and reduce blow by(neck sooting). Both affect ES with mid-size hunting cartridges.

For cases I can't trim this close, I don't really worry about trimming at all. I want these cases long as possible.
Between normal trim length variance -vs- gas blow by, I'll take the length variance.
 

MountainMariner

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Jun 22, 2014
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Alaska
I measure cartridge base to chamber end with Sinclair's gage.
Then I set the trimmer for -1thou.
With fire forming the necks will pull back more a small bit from this(~5thou), and given that I don't FL size, I haven't needed to repeat trimming.
Seems the trimmed stay within a few thou of each other.
The reason I like close is to mitigate carbon buildup at chamber end and reduce blow by(neck sooting). Both affect ES with mid-size hunting cartridges.

For cases I can't trim this close, I don't really worry about trimming at all. I want these cases long as possible.
Between normal trim length variance -vs- gas blow by, I'll take the length variance.

Sinclair tool to find out your rifles true chamber length.
http://www.sinclairintl.com/reloadi...s/sinclair-chamber-length-gage-prod32925.aspx
 

Gene

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Jan 23, 2007
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PA
I trim with a Wilson on a stand with micrometer adjustments. It is very accurate. Excessive trimming can encourage a carbon ring at the case mouth. Not taking enuf off, can lead to poor accuracy and potential danger. I try to stay about .005" below SAMMI. I measure every case length after sizing and then trim.
 

tbrice23

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Dec 12, 2012
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Location
Indiana
I make my own custom maximum chamber length gauge by cutting half the neck off of a once fired case. Neck size the case, seat a bullet .1" shorter than max then slip the half neck piece over the bullet longer than it should be. I make sure the neck tention on the short piece is just enough to slide when chambered.
Chamber the gauge a few times to ensure that I have a repeatable measurement.

All of my factory barrels max chamber length is .025" to .035 longer than sammi maximum . My custom barrels are usually reasonably shorter.

I always trim to .010 to .015 shorter than my max. Measurement if possible. But some of my brass never grow that long so, I trim them all as long as possible and exactly the same length every firing using the RCBS power trim pro with three way cutter heads. (It trims chamfers, reams and cuts all at the same time.)
 

Mike 338

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Feb 4, 2012
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Boise, ID
For rifles, I trim every time to book spec (or close to) with a Lee Case Length Trimmer. Sometimes they aren't the right lenght so you need to measure the finished product the first time but after that you should be gtg. I tend to think that leaving steps out of your regime can lead to bad habits.
 

barefooter56

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Joined
Nov 10, 2014
Messages
913
If you measure your cases and they need to be trimmed, how much do you usually trim off?



I’m curious of everyone’s opinions on this. Do you trim off quite a lot so maybe you won’t have to trim again after the next reload?



Or do you always try to get the case lengths to equal the same specific length every time you shoot?



Also, how close do you try to get each case length for “match grade” ammo? The hundredths (0.0X0)?



Thanks!
engineer40,
I use a SINCLAIR Chamber Length gauge to find what my actual chamber length is and subtract .010 from the gauge length. You have to know what's what and go from there.
 

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