223 Case Trimming OAL vs Neck Length

[tandmsimmons]

Sized cases will vary at the base, some sit at the top step some drop all the way in to the bottom step some in between. Trimming to OAL will cause a variance in neck length, trimming from the shoulders will cause a variance in OAL. I'm thinking that since an AR head spaces on the shoulder trimming for uniform neck size will yield better accuracy. Anybody have any hard facts on this?

[SixPointEight]

Not sure what you're talking about, but many millions of rounds are shot trimmed to OAL without issue

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[Whiterabbit]

he's talking about controlling where your variance is. If you uniform the necks, you open yourself the possibility of variance by shoulder. if you uniform your OAL, you open yourself to variance by headspace.

Each case we are talking hairs. But which one matters more?

FWIW, I haven't tested it. all my trimmers are OAL. But I will be buying a shoulder trimmer soon. But even then, will not be testing it vs OAL. So I'm not sure what the answer to your question is.

[tandmsimmons]

Whiterabbit - that's exactly what I meant. I'm thinking that consistent bullet jump to barrel is more important than case OAL where accuracy is the goal. I've got an 18" moa bull barrel, why not get the best out of it? This could all be resolved by measuring and sorting each case however that is a tedious business. Little Crow Gun Works makes a very handy case trimmer that is set at the shoulder.

[JagerDog]

Whiterabbit - that's exactly what I meant. I'm thinking that consistent bullet jump to barrel is more important than case OAL where accuracy is the goal. I've got an 18" moa bull barrel, why not get the best out of it? This could all be resolved by measuring and sorting each case however that is a tedious business. Little Crow Gun Works makes a very handy case trimmer that is set at the shoulder.

But you really didn't improve your bullet jump consistency if the case is moving in the chamber. The base is ALWAYS going to contact the bolt face and the shoulder is ALWAYS going to contact the chamber upon firing. Any slack is going to be taken up either way.