Case trimming- newbie question

johnnyreb65

johnnyreb65

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I'm using a Lyman Universal trimmer, and as expected my results aren't consistant as I'm getting used to what pressure to apply. I'm loading .223 which has a trim to length of 1.750..I set the trimmer to 1.751 to allow for excessive pressure on my part..I've pooched some cases and I'm not sure if I can still use them. My question is this, how short can you go before the case must be discarded? Is it dangerous if the case is too short? The shortest case is 1.743, most are in the 1.746 to 1.749 range.

What exactly does case length effect the most? Accuracy,pressure chambering. I'm shooting an AR15 with a heavy trigger and this rifle is more of my down to the range fun gun..Not really looking for dime size groups just proper cycling.
 
IMHO case length really doesn't really matter unless you get silly with the length. The key is to have all the cases the same length. I would say that if you are within 0.050" of book specs; you are fine.

Not saying that this is the best, but it is the way I do things for myself. Famous saying........"It works for me....take your chances if you use my information"
 
Many handloaders trim cartridge cases short so that the case does not need to be trimmed again during it's life. As to how short, I would not be inclined to trim away much more than half the case neck, and .223 cases shorter than 1.66" I would cull. The key here is that with the bullet in close proximity to the rifling, there must be enough neck to firmly hold the bullet in place. If your necks are very short, this will be an issue with light weight (read short) boat tail bullets. If your rifle has a long lead, this may already be a problem with cases trimmed to spec if you choose short bullets. An issue you might have with your AR-15 is that if you prefer to crimp your bullets, a heavy bullet might extend deep into the powder capacity. This is a minor sin in your case, as the long freebore resulting from the deeply seated bullet will reduce the high pressure that would otherwise occur.
 
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Just gave a rating to your post!

Even the 270 brass we formed from 30-06 cases ended up about 1/8 inch short and they didn't have to be trimmed for some time.
 
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