5.56 case length

[fstdraw]

I'm in the process of sizing a thousand or so LC 5.56 cases. All measure longer than 1.760, should I do my usual and trim to 1.750 or leave some long at 1.760? Would this be any advantage when I load a 5.56 type load with 62 gr. steel core and regular 62 gr. Hornadys? I've done thousands of .223/5.56 rounds, but trim most to 1.750. My favorite recipe is 55 gr Hornadys FMJBT over 25 gr. H335 over CCI 450 primer. I don't know if it's the most accurate load but it sure shoots nice. Input welcomed.

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[DizzyJ]

The trim length is identical on both. No advantage of one over the other.

Some people trim to length each time for more consistency. I tend to leave them alone until they go over 1.760"

If you're going to apply crimp, you'll probably want to trim to the same length each time so your crimp is consistent. I don't crimp any of my rifle loads so it's less critical to me.

 

[ThunderMtnOrd]

I trim mine to about 1.755 or so. When I gauge it, if it is a hair longer or a hair shorter, no big deal. Anything that is above the rim when I gauge it gets trimmed, anything at or below gets tossed in the ready pile.

Just make sure you get enough crimp on it.

 

[DizzyJ]

Anything longer than 1.760" needs to be trimmed. Otherwise you risk the case neck wedging into the front of the chamber which could lead to excessive pressures.

 

[fstdraw]

Gotcha. I trim everything so it's inside of 1.750 to 1.755. I now do shoot short cases (1.749 to 1.740) with good success. Great thing is no trimming on those! OK, 1.750 it is and I know I'll get at least two loadings until I need to trim again. I do crimp all with a Lee FCD-piece of mind.

The reason I originally ask about trim length was I see 5.56 in some reloading books shows 1.760 as length.

 

[DizzyJ]

Gotcha. I trim everything so it's inside of 1.750 to 1.755. I now do shoot short cases (1.749 to 1.740) with good success. Great thing is no trimming on those! OK, 1.750 it is and I know I'll get at least two loadings until I need to trim again. I do crimp all with a Lee FCD-piece of mind.

The reason I originally ask about trim length was I see 5.56 in some reloading books shows 1.760 as length.

Length should be 1.750"-1.760" on both .223 and 5.56

As you mentioned, even shorter (within reason) is not a bad thing. Some of my .223 federal is under 1.740" after initial firing.

1.760" is the MAX case length.

 

[fstdraw]

As I thought. Wanted to double check with the forum members that load a ton!

Thank you.