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

[NobullSKS]

I'm pepping brass for basic AR… nothing special and I'd count on it to run everything that fits …. All these cheap ones are way gassy…
Using case length template for quick reference (I don't usually process this much) but I have one. SAAMI max.
The cases that are a hair over I'm just throwing towards 300 blk cartridges. So not important now…. But
How are y'all measuring so much 5.56? I know a lot of you are pumping out a ton.
Does it really matter for plinking? I mean the regular ole AR should run them right? Or are you trimming each one? Or what is acceptable?

Read More

 

[415DET]

I trim all of my brass to 1.752 with my Giraud. It trims, chamfers and deburrs in one step. I have done 1000s and 1000s of them and I wouldn't process brass any other way.

 

[DizzyJ]

1.760" is the max length iirc.

 

[DizzyJ]

If it gets too long it'll pinch the end of the case into the bullet and cause overpressue issues.

 

[415DET]

From my Hornady manual. Vihtavuori recommends 1.752.

 

[NobullSKS]

Just an FYI…. I have a Lyman book with.223 rem in it. Same specs for measurements

 

[PiratePast40]

My new Starline brass is 1.747 and that's also the trimmed length using the Lyman E-Z trimmer.

 

[Pepe-lepew]

I was trimming every firing with a drill press. I now trim bulk 223 brass to minimum and use a x-die to resize to eliminate trimming it more than once.

I don't measure length before trimming. My drill press trimmer set up trims in about 2-3 seconds per case. It is faster to just run it through the trimmer no matter if it needs it or not.

For stuff like 30 carbine I run on a slower powered trimmer that takes about 4 seconds per case. I measure a sample and if most need trimming, they all go through the trimmer. If there is a significant amount that does not need trimming, I use my dial calipers to sort out which cases need trimmed. It takes less than 2 seconds to measure each case.

 

[msgriff]

Case length gauge, Lyman or Wilson. It's pretty fast.

 

[Local Loader]

I'm pepping brass for basic AR… nothing special and I'd count on it to run everything that fits …. All these cheap ones are way gassy…
Using case length template for quick reference (I don't usually process this much) but I have one. SAAMI max.
The cases that are a hair over I'm just throwing towards 300 blk cartridges. So not important now…. But
How are y'all measuring so much 5.56? I know a lot of you are pumping out a ton.
Does it really matter for plinking? I mean the regular ole AR should run them right? Or are you trimming each one? Or what is acceptable?

View attachment 1365826

So as far as trimming goes, I guage each case and each case that passes is put in one bucket to get final prep, an each case that's over max or is at max is put in another bucket to await trimming before final prep.

 

[Local Loader]

The thing to also watch for if you're going to do large batch 223/5.56 if you haven't done it before, is to watch for shoulder height and angle. If that's off than neck won't make much difference as it won't chamber right(in my experience). Size>clean>size>trim>prep
I'm sure you already know this but just in case, don't trim before sizing. If the case is way over size before cleaning than set it aside as a separate batch to clean>trim>size>trim>prep(only exception). Make sure to run a few cases through a case guage about every 10-20 cases after resizing to see if things well fit and/or if they need adjustment.

 

[gmerkt]

If it gets too long it'll pinch the end of the case into the bullet and cause overpressue issues.

Or won't go into battery because it won't fully chamber.

The template for measuring case length is only semi adequate. As previously stated above, the case length gauge is preferred. Because it also measures cartridge headspace.

Or, as also previously mentioned above, why gauge them at all? Because if you haven't trimmed them before, they likely need trimming. For uniformity if for no other reason. Some of us just run every .223 case through the trimming process, as most need it. If you trim to minimum length, they are probably good for a second go before trimming. .223's have fairly thin brass, they grow with every firing.

Uniform case length is important if you are crimping cannelured bullets for firing in an AR. So long as the cases aren't overlength, you can get by with a certain amount of variance with non-crimped bullets. Which will suffice for plinking accuracy.

I know a lot of you are pumping out a ton.

There are several methods of doing this, they all involve electricity. There have been some long threads on this subject here.

But don't think that everyone "pumping out a ton" is necessarily doing it as it should be done. Some of the "remanufactured" ammo offered commercially shows evidence of a lack of case trimming. For example.

 

[Nwcid]

I am another for just running them through the power trimmer. If it trims it was over length.

 

[dangerranger60]

Just as part of my prep process I run every case through the trimmer. any shorter than the trim length will not be trimmed, but it will catch any over length.
If the OP does not have a trimmer Lee makes a very simple one for around $20 that will do the job. it is not fast, and not the most uniform because it uses over all length instead of shoulder to case mouth for its measurement. But for general use it will get your cases a uniform length. and not too long.
I would rather my cases be a little short, rather than any over length. Good Luck DR

 

[DizzyJ]

Lee makes a very simple one for around $20 that will do the job. it is not fast, and not the most uniform because it uses over all length instead of shoulder to case mouth for its measurement.

Isn't OAL what you are wanting for the best consistency concerning case length?

If you're measuring off the shoulder wouldn't that possibly cause inconsistency depending on your sizing process?

 

[dangerranger60]

Isn't OAL what you are wanting for the best consistency concerning case length?

If you're measuring off the shoulder wouldn't that possibly cause inconsistency depending on your sizing process?

Because bottle neck brass headspaces on the shoulder That is the most accurate place to measure from. You won't get any inconsistency by measuring from there. Where if you trim based on overall length of an already sized case and the shoulder is bumped back you will trim a little long. If you trim an unsized case, you may be a little short. But measured from the shoulder it does not matter if the case is sized or not. That measurement will stay the same.
This is not true of cases that headspace on a rim.
I will add this, For most people's loading, any method of trimming will do the job. Most people will never be able to tell the difference by looking at their targets! If you trim based on OAL, your cases will not grow to a dangerous length. DR

 

[Koda]

Because bottle neck brass headspaces on the shoulder That is the most accurate place to measure from. You won't get any inconsistency by measuring from there. Where if you trim based on overall length of an already sized case and the shoulder is bumped back you will trim a little long. If you trim an unsized case, you may be a little short. But measured from the shoulder it does not matter if the case is sized or not. That measurement will stay the same.

Im not certain I understand this and its virtually opposite than what Ive learned. Case headspace isnt the same dimension as the chamber headspace. If you size first and bump the shoulder back your doing so from the case base, same for trim length. That should be consistent between the neck rim and shoulder, always. If you trim an unsized case from the case neck, the die will first move the case down including the shoulder, then when you draw the mandrel thru the neck to size that it will pull the neck away from everything below it, changing your trim length. Is that incorrect?

 

[415DET]

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

 

[Koda]

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

only after the case has been full length sized.

 

[415DET]

Koda,

Correct, trim after sizing.