Question about brass prep for precision reloading Nato LC 5.56

[0reo]

I've got all this once-fired Nato-LC 5.56 brass. I want to make as much of it as I can into match-grade ammo. So I start sorting it by head-stamp year but then I get to wondering if that makes any difference at all. As I'm sorting I'm noticing that even within a given year some headstamps look different then others and some have a different style crimp. So I'm figuring that there's likely to be as much variation of critical dimensions between cases of the same year as ones from different years.

So I guess that's my question: have you noticed any correlation between headstamp year and consistency of critical dimensions? Should I sort this way or skip that and proceed directly to sorting by case neck thickness / uniformity, case volume, case weight, etc.?

[rcoodyar15]

I've got all this once-fired Nato-LC 5.56 brass. I want to make as much of it as I can into match-grade ammo. So I start sorting it by head-stamp year but then I get to wondering if that makes any difference at all. As I'm sorting I'm noticing that even within a given year some headstamps look different then others and some have a different style crimp. So I'm figuring that there's likely to be as much variation of critical dimensions between cases of the same year as ones from different years.

So I guess that's my question: have you noticed any correlation between headstamp year and consistency of critical dimensions? Should I sort this way or skip that and proceed directly to sorting by case neck thickness / uniformity, case volume, case weight, etc.?

Personally I would not waste my time on that brass if you are truly trying to reload precision ammo.

Next is the rifle you are trying to load precision ammo for even capable of precision?

You might just be going down a road to frustration.

[opsoff1]

Don't waste your time - process all your brass the same way. Before you even begin, cull out the defects - badly dimpled cases, off center flash holes, split necks etc. Size, trim chamfer/deburr, remove the roll crimp on the primer pockets etc so that you have the same external dimensions for all the brass. After that, sort by weight - i.e. 1 or 2 grain batches, this will take into account any variations of wall / webb thickness (read internal volume). Don't even consider turning necks for a gas gun. LC brass is generally really good and pretty consistent. It does vary from lot to lot / year to year - but overall is of generally very good quality.

BTW - I don't sort by weight for anything other that 600 - 1000 yd ammo. Anything from 100 - 500yds get loaded from the same lot with the standard processing. The LR stuff get a fair amount of extra care.

[bfoosh006]

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[texasgunhand]

The federal American eagle 50gr varmint tipped .223 is amazingly accurate out of a 1/7 twist barrel.

By separating your LC brass by year will help keep constant seating depths when seating your bullets. That's the only reason I do it, to not to have to sit and adjust the seating die up and down saves a bunch of time if your trying to get the same COAL on every round.

[opsoff1]

The federal American eagle 50gr varmint tipped .223 is amazingly accurate out of a 1/7 twist barrel.

By separating your LC brass by year will help keep constant seating depths when seating your bullets. That's the only reason I do it, to not to have to sit and adjust the seating die up and down saves a bunch of time if your trying to get the same COAL on every round.

Separating by year has absolutely no affect on seating depths / OAL. Not sure where you came up with that - but respectfully, this is flat out wrong.

[0reo]

Sounds weird. If there is an explanation I'd like to hear it.

[markm]

Separating 5.56 brass by any measure is largely a waste of time in my experience. There are a few flavors of brass that have significant internal case volume variances. But for the most part I mix ALL my brass together for precision shooting. (.223 only... .308 is a different animal)

[texasgunhand]

You don't get mixed AOL useing mixed brass? To keep all cartridges the same OAL I have to back my seating die off and adjust it down to make sure they are all say 2.200 if not some are shorter or longer than others. Not a lot shorter or longer but some.

On just plinking rounds I would say it doesnt matter but for accuracy a few thousands either way in COAL can make a difference depending on what the rifle likes the bullet set at. There has been a few test targets posted here that show this extremely well.

Maybe it's time for me to get a new seating die. But I don't know how that could adjust automatically for inconsistent bullet lengths and thicker or thinner bases unless all brass is trimmer to exactly the same length. I have yet to find a box of bullets in pistol or rifle that were all the exact same length. Some vary a great bit.

Maybe iam just thinking more of useing mixed brass IE mixing Winchester,remington and LC all together. I just separate everything now into groups. Including LC by year.

[Waylander]

You don't get mixed AOL useing mixed brass? To keep all cartridges the same OAL I have to back my seating die off and adjust it down to make sure they are all say 2.200 if not some are shorter or longer than others. Not a lot shorter or longer but some.

On just plinking rounds I would say it doesnt matter but for accuracy a few thousands either way in COAL can make a difference depending on what the rifle likes the bullet set at. There has been a few test targets posted here that show this extremely well.

Maybe it's time for me to get a new seating die. But I don't know how that could adjust automatically for inconsistent bullet lengths and thicker or thinner bases unless all brass is trimmer to exactly the same length. I have yet to find a box of bullets in pistol or rifle that were all the exact same length. Some vary a great bit.

Maybe iam just thinking more of useing mixed brass IE mixing Winchester,remington and LC all together. I just separate everything now into groups. Including LC by year.

The cartridge COAL usually don't vary due to the brass and trim length. Unless you're crimping while you seat which I would highly recommend you not do. Somebody here can probably explain it better than me but crimping while seating can mess your COAL up and ultimately screw up your cases so I never went down that road.

Most people seat the bullet then separately use a Lee FCD to crimp. You'll still have a slight variance due to the same bullets being off a little but not much.