So I bought one of those Lyman case length tools, the one that has all the different case lengths machined into it.

The length are maximum recommended lengths. So for .223 is 1.760". I've been trimming everything to 1.750, with some of course being slightly shorter and not requiring trimming.

My question is, for generic plinking reloads. Is trimming even necessary? Should I JUST trim those that are longer than 1.760"? Does differing lengths affect the crimp on reloads all that much?

My opinion:
I trim every rifle case after sizing to the recommended length. Occasionally there are cases that do not need trimming but most will need it.
I have found that sometimes without trimming they will not chamber or be tight in the chamber. That could create excessive pressure as the mouth of the case gets jammed into the freebore.
If the cases are different lengths, then the crimp will be different creating inconsistencies.

PC

quote:

Originally posted by PCWyoming:
My opinion:
I trim every rifle case after sizing to the recommended length. Occasionally there are cases that do not need trimming but most will need it.
I have found that sometimes without trimming they will not chamber or be tight in the chamber. That could create excessive pressure as the mouth of the case gets jammed into the freebore.
If the cases are different lengths, then the crimp will be different creating inconsistencies.

PC

Okay, so I'm not wasting my time trimming them all back to 1.750. Or the ones that need it anyway, seems about 75% of them require some amount of trimming.

quote:

Originally posted by OttoSig:
(snip) seems about 75% of them require some amount of trimming.

Cases stretch when fired. That is why we trim them to factory specs to fit in the chamber.

PC

As long as it is within spec, I don't trim my .223 brass for general plinking loads. Ive gone to using the Lee crimping die, so case length is no issue.

Not every chamber is the same size. You can get a chamber gauge and measure exactly when you need to trim for your rifle. It is super easy to do.

https://bulletin.accurateshoot...hamber-length-gauge/

Or:

https://www.brownells.com/relo...chamber-length-gage/

I trim as needed, yes measure each. Some are a tad short for whatever reason, ok.

After trimming, a little champher & debur, to take the edges out.

I’m in the casual shooter, hunter, at times prairie dogger. I want reliable ammo with acceptable accuracy. Often I’m also loading for any of several rifles or handguns. That’s another consideration with reloaded ammo.

Cases that are consistent in powder capacity and length will produce tighter groups with consistent pressures. You can see this also when you chronograph your reloads. The standard deviation will tend to be lower, ie., less spread in velocity readings.

Sorting the brass and putting them through a gauge is definitely worthwhile. I use an LE Wilson case gauge. It speeds up the process. I also use a digital caliper a lot. I trim cases with a power screw driver and the Lee trimming tools. There are no doubt better and/or cost effective ways of doing it. I'm still learning new tricks after starting reloading in 1980.

Uniform case length does matter even when using a Lee crimping die.

Case Trimmer

As stated above, it absolutely matters and using the Lee crimp is more consistent when they are all the same length. For me, shooting is about consistency and confidence, the consistency is why I reload, all my rounds are the same and that adds to my confidence.

I use the Frankfort arsenal trimmer above, you can feel it trim to length and when you get a real short case you can feel it do nothing so I put them aside. It also reams, deburrs, and removes the primer crimp of military brass, and you only have to handle the case once...it's fast...

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