Case Trimming?

[Ernest T]

I use the Lee case trimmer which uses the case base to set the length of the case. I like it because its easy and repeatable, but I've seen and read some things that say that's not the best way to trim a case. Any thoughts about measuring from the shoulder?

[bootsmcguire]

I have used that same Lee system for years with no issues, not saying it is the most productive way but it works. I would think measuring from the shoulder may be less accurate because one would be taking for granted that all other measurements from that junction on the shoulder to the base are equal from 1pc to the next. Maybe there is a tool or system for that, I don't know at this time. Trimming is chore that I am never excited to do and as such my higher volume shooters are mostly Ackley Improved chambers which practically eliminates trimming and with the added brass life I use them when practical. But that's another topic Lol.

[Blue Avenger]

Even if they can show it's better, I'm not going to add a new method into the program at this stage. They fit the Die, Crimper and chamber with my current trimming tooling. I'm not currently pursuing 1000yd moa.

[Dave Hoback]

I use the Little Crow trimmer & measure the old fashioned way; “How it was done back in 19-Aught-Eleventy-12!”

[Ernest T]

I've been working on the theory that no matter where you measure from, you trim the same end so what difference does it make? I've seen shooters who advocate indexing off of the shoulder, claiming the critical measurement is shoulder to end of case neck. I can't see how you can do that and get consistent overall length.

[Stumpkiller]

I've been using a Lyman Universal hand-crank trimmer since 1980 or so. Indexes on the head.

[Ernest T]

I started looking the Lyman Case Trim Express and realized it trims the case without reference to case length. That got me to wondering why, so I did a little web searching and now that I understand the difference, I'm wondering why again.

[GaCop]

I've been using a Lyman Universal hand-crank trimmer since 1980 or so. Indexes on the head.

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[engnman]

This

I've been using a Lyman Universal hand-crank trimmer since 1980 or so. Indexes on the head.

[Balvar24]

I use the Lee case trimmer which uses the case base to set the length of the case. I like it because its easy and repeatable, but I've seen and read some things that say that's not the best way to trim a case. Any thoughts about measuring from the shoulder?

I chuck mine up in an electric screwdriver to make it a little quicker. Drill spins too fast for me.

[Ernest T]

Thanks for the replies.

I'm on the 4th reload of my Lapua 6.5 CM brass. I've trimmed the cases every time I've reloaded them, going on the theory that everything being consistent is better. Now, I'm not cutting much brass so that's why I asked about how much a case stretches when its new vs an older case. I'm definitely not running high pressure in my reloads.

How do you use a case trimmer that measures off the shoulder? My cases have varied very little after firing - in other words, all of them were within a couple thousandths of an inch of the same length. In theory, I could measure a few to figure out how much I want to trim, then set up the cutter to trim that much. I'll end up with cases that are in spec for overall length, but vary in length from each other by that same few thousandths of an inch. Is that a concern? The alternative is to measure each case and adjust the trimmer to cut it to a specific length. That seems super tedious.

[charlie b]

Everything is really based on the shoulder to base measurement. This is dictated by the headspace in the rifle. You set your resize die based on that headspace. Trimming the neck is only to keep it from hitting the end of the chamber. A little shorter is not the end of the world, but, too long and it will jam the neck in the throat and 'crimp' the bullet. Extreme cases cause big pressure spikes.

Since the headspace is based on base to shoulder measurement, then the simplest case length measurement is base to end of neck. As long as your cases are prepared the same, measuring/trimming based on the shoulder will get the same results as measuring/trimming based on the case base.

Bottom line. Set your trimmer of choice so the neck does not enter the throat. Do it the same for every cartridge case. Doesn't really matter how you accomplish that.

[ramon]

I use the lee trimmer for most of mine. Also have the forster trimmer for the ones that the case length gauge is not available.

[nksmfamjp]

I use the Lee case trimmer which uses the case base to set the length of the case. I like it because its easy and repeatable, but I've seen and read some things that say that's not the best way to trim a case. Any thoughts about measuring from the shoulder?

If you are happy with the Lee, it’s not bad. The only issue I ever had was uneven cuts for some reason. That said, I still use some.

Measuring from the shoulder works too and those type…like my Trim It 2 are good for high volume normal accuracy level. It just isn’t the dimension on the dwg. Often that is important. I’m not sure it is super important here because most chambers have room and length consistently is not accuracy critical, IME.

I've been working on the theory that no matter where you measure from, you trim the same end so what difference does it make? I've seen shooters who advocate indexing off of the shoulder, claiming the critical measurement is shoulder to end of case neck. I can't see how you can do that and get consistent overall length.

I see that stuff too. Piss those folks off by telling them they are not following the dwg!

So the consensus is measuring from the base is the way to go?



Does brass stretch more when new and less as you reload it multiple times?

Brass stretches the most when new. Blowing it out to match the chamber and then sizing to min dimensions with std dies is the biggest shape change in brass’s life. Some dies and setups oversize which will cause excessive trimming.

[rerun5]

I have used the Lee trim system since I started reloading and even though it isn't the quickest, it is simple and accurate enough for me.

[Palmafiddleman]

I use a tool called "Quick Case Trimmer" sold by Possum (sic) Hollow. I think I got it from Sinclair Intl. It indexes off the datum line. I like it because it is fast and I can chuck it it my hand drill.One might get carpal tunnel turning a crank repeatedly.

[want2ride]

Everything is really based on the shoulder to base measurement. This is dictated by the headspace in the rifle. You set your resize die based on that headspace. Trimming the neck is only to keep it from hitting the end of the chamber. A little shorter is not the end of the world, but, too long and it will jam the neck in the throat and 'crimp' the bullet. Extreme cases cause big pressure spikes.

Since the headspace is based on base to shoulder measurement, then the simplest case length measurement is base to end of neck. As long as your cases are prepared the same, measuring/trimming based on the shoulder will get the same results as measuring/trimming based on the case base.

Bottom line. Set your trimmer of choice so the neck does not enter the throat. Do it the same for every cartridge case. Doesn't really matter how you accomplish that.

I was going to type pretty much everything you wrote. If i was set up to do it a different way in the beginning, i might do it different. But, when i first started my brother pointed me to use the World's Finest Trimmer, and it is just so fast and easy that i am not going to change. He has moved on to a Giraud, but i am happy where i am.

[Mr.Snerdly]

I think it is perfect. I bought a used RCBS trimmer and it was far from accurate. The Lee gets them all nearly perfect and it is faster, at least if you have a small drill and I don't know anyone that doesn't have a 1/4" or a 3/8" drill.