Ar 15 trim question

[OleEd]

I have been loading pistol rds for a long time but this is my first time on 223 Remington rds for my son in law. My book says to trim brass to 1.750 which I have attempted to do.... I was doing it with a hand trimmer and realized that for the number of rounds my sil will shoot, I bought a machine trimmer. Thank goodness. I have a bunch a rds I had hand trimmed shorter than 1.750. They range from 1.749 to 1.741 and I can't find a place that gives a tolerance of a +/- for trimmed brass. Would appreciate any of you AR15 shooters- reloaders your suggestion as to a +/- tolerance zone I can use (ie, 1.740 -1.755??????). Hate to toss out a bunch of brass if they can be used. This is for sil to bang at tgts - not hunting.

Thanks in advance.

 

[rcmodel]

You can use them if you don't try to crimp them in the seater die.

If you just have to crimp, get a Lee FCD collet crimp die.
It operates off the shell holder, and doesn't care much about case length.

rc

 

[carbine85]

The amount you are talking about is very small. Mine always very a small amount. Make sure your case holder is tight. If the overall length problem is in the neck you are ok, if it's in the shoulder you might have a problem with the die and that needs to be corrected.

 

[Hondo 60]

They range from 1.749 to 1.741

While they can be used, that kinda defeats one of the reasons for trimming.

See rcmodel's post above.

 

[highbrow]

I always trim mine a little shorted than spec. That way I don't have to trim as often.

 

[Cherokee]

Use them, they will work fine as long as the headspace is good. I would try some sized cases in his rifle chamber before doing any more just to make sure the headspace is good.

 

[edfardos]

1.745" here.

 

[GLOOB]

I've seen factory cases as low as 1.731" after the first firing.

Like many others, I trim shorter than 1.750", so I don't have to trim as often. Trimming down to 1.745" or thereabouts, I only ever have to trim about 15% of my cases on each go around.

 

[StandingTall]

...I can't find a place that gives a tolerance of a +/- for trimmed brass.

Tolerance zone is 1.760" -.030". Here are the SAAMI specs for that cartridge:

.223 Remington SAAMI Specs

 

[hentown]

The instructions that come with .223 X dies call for an initial trimming of 1.740". Trimming too short has no effect on headspace...AT ALL.