max case trim question

[vulcandeathbuny]

Im reloading for 223 and fairly new to the hobby. I've been saving my brass and got ready to reload, I had a good first batch of reloads. However some of my once fired brass was shorter than max trim length. Is it still ok to use and what problems can I encounter if I use it.

 

[cfullgraf]

Maximum trim length is the longest that you want the case to be, so shorter is better.

Generally, information on cartridges have a "maximum trim length" and a "minimum trim to length". These are usually 0.010" apart.

So, when the case exceeds the maximum length, it needs to be trimmed. Most trim to the minimum so that they do not have to trim the case as frequently.

If you insist on crimping your 223 Remington, it is desirable to have all the cases at the same length. It makes for a more uniform crimp from case to case. But, crimping the 223 Remington is not necessary. I do not crimp my 223 Remington ammunition.

I measure my 233 Remington cases after each resizing. Any that are too long get trimmed. Any that are under the max length do not get trimmed.

Hope this helps.

 

[dmazur]

Resizing with FL dies generally causes cases to "grow".

Standard practice is to measure case length after resizing and trim to the recommended "trim to" length, which is usually 0.010" less than maximum case length.

The trim to length is quite a bit shorter than maximum so that trimming isn't necessary after every resizing, which might be true if only 0.002" was trimmed.

In general, as long as a case is shorter than maximum and the rifle's chamber is SAAMI spec, there is no danger of the case mouth being pinched by the rifling, which can cause dangerous increases in pressure.

While there is no published minimum, it is possible to trim to the point where there is insufficient neck for bullet retention.

 

[witchhunter]

Don't worry if they are a littile short, only too long. If you are loading a LOT of .223 I would recommend a power trimmer. I load in batches of 2-500 and it is az big help.

 

[oldpapps]

As stated above, your good.

At one time I was doing a lot of load experimentation with the 300 AAC Blackout. I was reloading the same brass 25 and more time. I was experimenting with a set, trimming to much shorter than normal (1.345 inches to the regular 1.363 inches). First, the loads worked the same. The brass lengthened very close to the same amount with each reload. I didn't get to complete this test, I stupidly sold the rifle. It was close enough for me to think that I could 'over trim' and have no concerns with my brass lengthening to a danger point in several reloads.

To your point, as long as you have suitable neck to provide proper neck tension, I don't think bottle necked brass can be trimmed too short. That doesn't mean that I'm going to chop off my brass real short.

 

[gamestalker]

Did you measure before or after resizing?
And as already posted, it's max length that is important. If too long, the mouths can pinch in the throat when fired, thus causing extreme pressure spikes.
GS

 

[vulcandeathbuny]

I measured after sizing and some were .010 shorter than trim length. I use hornaday 9th edition reloading manual. Max case lenght 1.760 and trim length of 1.750. Quite a few measured at 1.745-1.740. The bullet seated fine and they chambered well.

 

[scottishkat]

short cases

I recently purchased some new unfired lapua brass and approx 40 out of 100 were short. After firing it is common for cases to widen in the chamber of some rifles. My Sako 85 does this .015 is alot though genrally Irun the case through a body die or a full length resize and that will lengthen the case back to it previous length. Shoot away it does make it difficult if you are weighing brass to obain common pressures.