Overall case length queries.

Hi all I have just recently decided to get into reloading and have just cleaned resized, trimmed and chamfered/debured my first bit of brass (100 once fired Sako .308 brass from factory loads). Before doing anything to them I randomly measured a few and found that the lengths weren’t very consistent. With all being done here are the results;
23 of them are 2.010”
41 of them are 2.009”
20 of them are 2.008”
8 of them are 2.007”
5 of them are 2.006”
And one outlier of 2.003”
So I was wondering what is an acceptable difference is and what causes them to be smaller (I’m using a Lyman hand trimmer that has calibre guides to trim to)


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Trim to same length , then sort by weight
Cases will "grow " from repeated firing
Most dangerous thing short from double loading

I’m just gonna trim them after every fire with the same Lyman guide to keep it uniform


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peace of mind, you can make yourself a tool to check. Get a paper clip, straighten it out enough so it can reach the bottom of the case. Make a small 90 degree bend on the end of the straight section. Scrape the inside wall with your new tool. You're feeling for a dip in the wall instead of a smooth transition. If you can feel an obvious valley, toss the brass. If it's smooth, keep it

I’m confused what wall?


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Hes talking about case separation. Its when the case splits around the circumference and splits in half. Handy thing to know but personally I wouldn't worry about it on a first firing of a factory load. Trim them all to the same length, consistency is the secrete to accurate reloading.

Were these rounds fired in your rifle?

Yup
Tikka t3x


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Dont go too hot on the loads and your cases will last longer. You could look up the saami measurements and trim to that. I just use the hand lee case trimmers. Once you trim them all the same and check them after a few firings you'll figure out when they will need trimming. Im not fully sure on this but I'm under the impression its to do with the rifles chamber as to how much the brass stretches plus how hot you load eg I have 2 rifles in the same caliber and I run the same load in both of them. One rifle i have never had to trim the brass and the other one it needs trimming every 2nd to 3rd firing.

A Wilson case gauge can be a handy thing for a quick Check on head space, and length.
I run my brass though after sizing to check for length and head space.
However I also cycle my lever action brass though the rifle I'm loading for as well. Some I find need an extra bump to let the action close smoothly.

https://lewilson.com/gages

Z

A human hair is about 3 thousandths of an inch thick. There's other variables that'll have waaaay more effect on your loads than such a tiny difference in neck length from case to case.

Let the short ones grow until they're the same as the longer ones. Keep them under max (2.015") and you won't have any problems.

Natural variability in the brass means they aren't all going to grow at the same rate.

Trim to 2.005". (Max 2.015")
Just relax. Experience has taught me they can vary a lot from new.
Trim them all to 2.005". If a couple are less dont worry they will grow as u use them.

I find it easiest to trim each time they get loaded.
I just use a dial vernier to measure them.

FFS just buy Lee trimmer and be done with it

And spin it in the cordless micky duck

Greetings @SamRoche,
Welcome to the giant rabbit warren of handloading. I had a look on the Lyman site and I think that the trimmer you have is the Lyman version of the Lee. The pilots should give you good results without measuring but you do get a feel of when the trimmer stops cutting after a while. None of your case lengths are over max so you don't have a problem. One thing that may help is to chamfer the cases inside and out after trimming and then trim again which may give a more even result. Lyman has a how to video that you can watch.
Please find a mentor before you start putting your loads together. They will help you set up your kit as there are a few traps for the unwary most of which I have encountered over the years. There is plenty of pressure tested load data available from the likes of ADI and Hodgdons plus others. Please ask if you want suggestions. The .308 is a delight to load.
Regards Grandpamac.

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Originally Posted by Sharki

And spin it in the cordless micky duck

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spin to check length,then while still in drill,do the debur thing,if feeling really flash grab your bit of abrasive cloth and polish case body at same time. remove ,place in block...next please.....

If you can find somebody local to you who runs an amp annealer
you will find this variance dramatically reduced. I normally set mine up for a shoulder bump of 1thou from fired. I'm in Auck unfortunately or I'd anneal them for ya.