Max case length question

[ghbucky]

SAAMI sayeth that max case length for .223 Rem is 1.760

My once fired, full length sized cases are measuring 1.763. They fit in the gauge, and I chambered a case in my AR, and the bolt closed using the forward assist, and ejected with no issue.

Can I get by with not trimming these until the next firing, or am I asking for trouble?

 

[Bart B.]

You may be asking for trouble.

If the case shoulder is set back too far from firing pin impact, that may drive the case mouth into the chamber mouth.

Case neck length from shoulder to mouth should be at least .010" less than that of the chamber. This is the critical dimension for your rifle.

 

[Unclenick]

The neck portion of a chamber usually has ten or twenty thousandths of extra room for the occasional error in case length, but with so many different variations on the 223 chamber around, I would make a chamber cast or tap a soft lead slug to upset it in that area of the chamber to get a measurement to be sure.

The SAAMI number is the maximum case length. The tolerance for the 223 is -0.030" (an increase from -0.020" in the 1992 standard), so the current specification is a range of 1.730" to 1.760".

 

[44 AMP]

Just trim the darn things to 1.750" and then don't worry about it for the next 2-3 firings.

 

[mehavey]

Just trim the darn things to 1.750"

^^^^^ THIS ^^^^^

 

[higgite]

and the bolt closed using the forward assist

I'd say there's a message there. I'd trim to 1.74" and not have to trim again for a few firings.

 

[burrhead]

I trim to 1.74 and by time they reach 1.760 I put them in the "hard times" box.

 

[rmh3481]

Crimp them hard, otherwise trim. If you have a short chamber (non nato or 223) I would trim them. Wont take but a stroke over a file.

 

[Don Fischer]

Trying to get away with something could be your down fall or not Ya won't know till you try. But then knowing what you know why would you try to get away with it in the firs place?

 

[ghbucky]

Yeah, I trimmed them.

 

[cdoc42]

I'm in the middle of reloading my AR-15 in .223 and after resizing cases I measured them to find I need to trim at least 4 of every 10. I have at least 500 cases to play with, so I pondered the same question you did. In addition, in my inventory I have about 2000 cases, many of which have primer pockets that must be swaged in order to accept a new primer. That's more of a pain than trimming.

But - I'm trimming and swaging because that's what's necessary unless I want to buy all new brass.

 

[scatterbrain]

I check the length of every case, in my trimmer. If it is pistol or rifle, every case goes in the trimmer for a length check, too easy not to. You are using your bolt close assist to check yours.