5.56 brass length for AR…. “Acceptable” over SAAMI ?

[DizzyJ]

The Giraud trimmer indexes off of the case shoulder for trim length.

Yes it does. However any variation in shoulder bump will lead to variation in OAL trim length.

 

[415DET]

Yes it does. However any variation in shoulder bump will lead to variation in OAL trim length.

Do you get variation in your shoulder bump when you size? I set my die up once and have sized 1000s of cases, and get consistent trim length at 1.752.

 

[DizzyJ]

Do you get variation in your shoulder bump when you size? I set my die up once and have sized 1000s of cases, and get consistent trim length from at 1.752.

Whether I do or not doesn't change the fact that trimming based off of the base of the cartridge is going to give you the least amount of variation possible.

It's not too hard to have a variation of +\- .001" when bumping the shoulder based on speed, lubrication, brass hardness and other variables.

 

[415DET]

I imagine that could be true. I do know that the Giraud trimmer is used by more nationally ranked highpower shooters than any other trimmer, maybe a Gracey would be a close second. It has served me well for the past 10 years or so of competitive shooting, and I wouldn't use any other tool to trim my brass. I would absolutely recommend to the OP that they trim their brass to avoid problems.

 

[Koda]

In mfg I always avoid chainline dimensioning to avoid tolerance stackup. If you size within +/-.001" thats pretty good. If you trim off the sized case shoulder +/-.001" thats pretty good too. But your tolerance from the base will be +/-.002". Thats probably pretty good too, but this is assuming your good enough to never vary more than +/-.001" in any step.

My guess is that anyone that can afford the Giraud trimmer is also pretty good at handloading. Maybe +/- .002" case length doesnt matter.

 

[Member 34319]

I've been trimming large quantities of brass using the worlds best trimmer. It uses the cases shoulder as a gauge to trim. I'm consistent with how I size and I'd say it's been consistent because of that. I'll go measure up a batch and see what the variations were.

 

[NobullSKS]

I've been trimming large quantities of brass using the worlds best trimmer. It uses the cases shoulder as a gauge to trim. I'm consistent with how I size and I'd say it's been consistent because of that. I'll go measure up a batch and see what the variations were.

Which trimmer is that?

 

[Member 34319]

Which trimmer is that?

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