Brass Trimming

arwaterfowler

Active Member
Dec 4, 2011
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Omaha, NE
Folks,

I'm a fairly new reloader. I've reloaded about 1000 rounds of pistol cartridges and just started reloading rifle rounds. I'm currently working up a load for 300 WSM. The Hornady and Nosler manuals call for a trim length of 2.1".

I've got the following brass at the stated trim lengths...
20 rds Federal @ 2.09" (once fired)
80 rds Nosler @ 2.1" (once fired)
25 rds Nosler @ 2.08" (brand new)

Do I trim the Noslers (once fired) to 2.09" assuming the new Nosler brass with lengthen after firing? Or trim everything to 2.08"?
 

AKaviator

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Jul 26, 2012
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Personally, I wouldn't worry about trimming any of them yet. If you're loading for hunting and not necessarily precision shooting the difference in length is too minor to have an effect. I only trim when cases get close to the listed maximum length.
 
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Colorado Cowboy

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Personally, I wouldn't worry about trimming any of them yet. If you're loading for hunting and not necessarily precision shooting the difference in length is too minor to have an effect. I only trim when cases get close to the listed maximum length.
Spot on. Another question is have the brass been run thru the sizer die? I usually trip after they have been sized because they can move some after sizing.
 
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Bonecollector

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Mar 9, 2014
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Personally, I wouldn't worry about trimming any of them yet. If you're loading for hunting and not necessarily precision shooting the difference in length is too minor to have an effect. I only trim when cases get close to the listed maximum length.
10-4 Bob.
I wouldn't disagree for general hunting and 1-moa shooting. However, it does affect things for us target shooters and does become noticeable after 400-500 yards depending on the loaded ammunition specs.
 

mallardsx2

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Jul 8, 2015
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I am no expert but I do some reloading. Many others may have better advice.

I would go ahead and fire form those brand new brass. Then, I would Full length re-size everything to .003" back from the shoulder.
Having said that if your going to mix brass, (which I do a lot because I am no ribbon chaser) I would trim everything to the same length to 2.090".

Since I dont segregate cases by brand I at least keep everything consistent when it comes to bumping the shoulder back and my C.O.A.L.

Then I go up the powder by 1/2 grain increments from min to max watching for primer flattening and of course group size.

Once I get MOA I call it a day.

9 out of 10 precision reloader's mothers may not recommend my above advice. lol
 
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AKaviator

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10-4 Bob.
I wouldn't disagree for general hunting and 1-moa shooting. However, it does affect things for us target shooters and does become noticeable after 400-500 yards depending on the loaded ammunition specs.
B.C. I agree completely. I just don't shoot very far. I do trim for consistency but only when they lengthen out closer to max or when I use a crimp groove to crimp into. I'm a 300 yard or less kind of guy!
 

Colorado Cowboy

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I do have a case length guage and measure my brass probably every 8 to 10 reloads. The only time I do measure after every load is my .220 AI Swift. It hummms along at over 4,000 fps and I usually have to trim the brass after 4 or 5 loads.
 
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