Question about brass prep for precision reloading NATO LC 5.56

[Oreo]

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.?

[montana_charlie]

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.?
I haven't reloaded any, so what I have to say is 'general' in nature.

I would separate by headstamp ... mainly because it has been done that way for a long time.
Then, within a given year, I would separate (again) by that difference in appearance that you mentioned.
Once you get down to a sizeable group pf 'identical' cases, I would check them for internal capacity.

That would be done by weighing them ... or by finding out how many grains of water each can hold.

When you can get a 'batch' (you get to decide how many makes a batch) of perfectly matched cases, load them and shoot them for accuracy.

Then compare that batch with another that came from further back in the 'separation' process.

That should give you an idea of how picky you need to be to get the quality of result you want.


It may turn out that simply separating cases by weight (headstamps mixed) will give you sufficient uniformity.


As for any 'critical dimensions' ... your reloading dies will make the dimensions uniform.

CM

[williamwaco]

If you are going to weigh water capacity you should full length resize first. Otherwise you will be measuring the size of the chamber they were fired in.

Also if you are filling to the mouth, trim them first.

[Vann]

When I load for accuracy with new or once fired cases, I clean and deprime them first then sort them by weight. You have to do this before you trim them or do anything that may alter their weight from the factory. I generally try to get them to all weigh the same but have accepted them with up to +/- 1 grain. It really depends on how precise you're trying to get. The only time I use water is if I'm loading to max then I try to figure case capacity. In reality if you are loading I'mheavy cases a light case should have a larger case capacity therefore your max load should be safe.

When sorting cases by weight the thing to remember is that .5 grain weight+/- has less affect on a large case such as a 30/06 where as it will have a larger affect on a small case such as a 223 or 22 Hornet. On 223 I try to stay within +/-.3 grains.

Just my opinion, by no means the gospel.

Vann

[Pipefitter]

For once fired military brass I clean, resize, swage the primer crimp, trim and uniform the primer pocket with a Sinclair tool, and deburr the inside of the flash hole before any sorting by headstamp or weight. All cases are the same dimensions before sorting this way.

[wordsmith]

Oreo - I guess it depends on what you mean by precision reloading. I've done a lot of loading with LC brass, in both 308 Win (as 7.62x51 brass) and 223 (as 5.56 brass). I've found it (LC brass) to fall in what I'd consider the better third of 223 brass regarding "precision" quality. That means, generally, that neck thickness variation on a given cartridge measures about 0.0015" +/-, case to case variation is 0.003" +/- and water capacity is 31.1 grains, with an SD of 0.14 grains. WCC is almost identical in these specifications.

I say all that to say that no matter how well you size the brass with a Redding Body Die or bushing die, how precisely you seat the bullet with a competition sleeved seating die, or how closely you measure the powder charge, you are ultimately limited in accuracy by those case thickness variations. In that regard, you can do very well with LC brass, and I use it for 90% of my 223 shooting, but Lapua or Norma is required IMHO to wring the last bit out.

[Oreo]

I built what should be a decent "varmint" style AR15 that should be capable of sub-MOA with jacketed bullets. I'm trying to get it there but I'm not obsessed with achieving bug-hole groups. I've done lots of pistol reloading but minimal rifle reloading. Hence, trying to be thorough now.

[Vann]

If you're just after moa accuracy you can probably get that just by taking your time and working up a load without a bunch sorting, just use the same headstamp.

[Frank46]

I've done this with 308 win cases. Prep the brass first. trim to length, swage or use a primer pocket reamer to remove the crimp and uniform both the primer pocket and flash holes.The swaging would be for military cases. Then if you wish weigh them. Mark with magic marker and sort into groups. Somewhere you will have groups that have a lot of cases within a certain grain weight. plus or minus whatever weight you wish. I once did 500 30-30 cases and ended up with about 200 that fell within plus or minus 2 grains. Now having said all this it would take an extremely good shot ( no reference to your shooting ability) to see the wisdom of sorting by weight. Match prep them and shoot them. I had a very good friend who got bit by the accuracy bug. Did all sorts of prep and neck turning. And he used lapua 308 cases. yeah his groups were great but I once said how much accuracy do you really need. Just for grins and giggles I did match prep 100 lake city 5.56 cases and loaded them with the 69 grain sierra bullet and easily got sub moa groups from a match H-bar that I still have. But that same rifle would do 1" groups with lake city ball. Frank

[wordsmith]

I built what should be a decent "varmint" style AR15 that should be capable of sub-MOA with jacketed bullets. I'm trying to get it there but I'm not obsessed with achieving bug-hole groups. I've done lots of pistol reloading but minimal rifle reloading. Hence, trying to be thorough now.

You should be able to break under MOA with a decent barrel and bullet, along with good reloading practices. I have a very similar "frankenrig" with a WOA 20" barrel that does sub-MOA all day long with unsorted mixed military brass. The key with rifle is to find a barrel harmonic node through a laddering round-robin type test. Google "Optimum Charge Weight" for Dan Newberry's site and proceed accordingly.

[Smoke4320]

For once fired military brass I clean, resize, swage the primer crimp, trim and uniform the primer pocket with a Sinclair tool, and deburr the inside of the flash hole before any sorting by headstamp or weight. All cases are the same dimensions before sorting this way.
above Correct Way to sort Mil Brass for accuracy proposes..
Sort by headstamp first ...
There are some years of LC brass that are known to be more brittle and will not last as long) I don't remember them right off but shooting in the sorted lots you will find these out quickly .. as soon as I see 2 or 3 split necks I toss that whole lot ...
then do all prep first ..
Then sort again by weight (within the year) for long range accuracy +/_ .2
IE: case weight 29.2 to 29.6. ECT ECT
This will give you lots to shoot from.. I
just pick the lot with the most cases shoot them till worn out.. toss go to next lot ..
Its also easy to add new found/purchased cases to the old sorted lots once the prep is done
also annealing the LC cases after all prep is done and again about every third firing will double case life

[wordsmith]

above Correct Way to sort Mil Brass for accuracy proposes..
Sort by headstamp first ...
There are some years of LC brass that are known to be more brittle and will not last as long) I don't remember them right off but shooting in the sorted lots you will find these out quickly .. as soon as I see 2 or 3 split necks I toss that whole lot ...
then do all prep first ..
Then sort again by weight (within the year) for long range accuracy +/_ .2
IE: case weight 29.2 to 29.6. ECT ECT
This will give you lots to shoot from.. I
just pick the lot with the most cases shoot them till worn out.. toss go to next lot ..
Its also easy to add new found/purchased cases to the old sorted lots once the prep is done
also annealing the LC cases after all prep is done and again about every third firing will double case life

This is very solid advice, and I would suggest that if you really want to go all the way that you need to then sort by neck thickness uniformity, both by individual case and by grouping overall similar thicknesses together. I have found this will give very similar neck tension and minimize total indicated runout, which are a couple of key ingredients for top accuracy.

[zarrinvz24]

Pipefitter has it right. Need to ensure all variables are consistent prior to any sorting. Think of it this way. LC makes billions of rounds per year using multiple machines for all parts of the process. Just because the headstamp is the same does not mean that the brass is the same. Resize, trim and uniform then compare by weight.

[wordsmith]

Some good overall advice here, although I would again caution that you should temper expectations for accuracy with LC brass. As zarrinvz24 points out, they make a whole bunch of it every year, and while it's good stuff (especially for autoloaders), it's not Match quality brass. It will definitely go MOA or slightly better, but you will eventually hit a wall due to runout caused by case wall thickness variations. You can turn necks if you want to tighten it up a little, but that's a lot of work for a marginal gain. Take it from someone that has been down this path already.

[Oreo]

Well, fortunately I've got enough brass and enough time to sort it and prep it in every possible way. I intend to debur flash holes, uniform primer pockets, neck turn, weight sort, and concentricity check after loading.

This is for my AR15 so there is that. If I can get .75moa I'll be happy. .50moa and I'll be tickled pink.

[wordsmith]

Sounds good, keep us posted. I always like learning from others experiences.

[Oreo]

I am interested in learning, testing, first hand whether there is any quantifiable difference in lot years. I'm betting not but I did sort the brass already. Took me all week but I did it.

[EDG]

Pick a large lot of the same head stamp and prep it completely. Then wash to get rid of all the chips from trimming.

Weigh the brass and sort it into .2 grain bins in excel or equivalent.

Then graph the distribution.

You should get a bell curve.

There will be a group of heavier cases on the right. Set them aside to work work up loads with.

There will be a group of lighter cases on the left. These are used as spares or as a smaller lot of ammo.

the middle 50% to 66% of the weight distribution are your best cases to use for accuracy.

[Oreo]

I've got something like 1500 of '11, and another 1500 of '12 as my two biggest lots. That should give me plenty to work with.

[David2011]

If you're just after moa accuracy you can probably get that just by taking your time and working up a load without
a bunch sorting, just use the same headstamp.

Couldn't agree more. IMO the critical component of .223 ammo is the bullet. I fought accuracy with my AR for the longest time until I tried some good bullets one day. Mil-spec bullets shot 2-1/2" to 4" patterns. The first 5 Sierra MatchKings down the barrel made a single ragged hole. BLC-2, 748, H335, Varget and a few others were tried in ladders with every primer I could get my hands on and all shot equally poorly until I tried some quality bullets.

I have since developed the opinion that with this particular rifle just about any load of any of the powders commonly used for the .223 cartridge will produce decent accuracy. The rifle has a 16" bull barrel. I think the fat barrel is less subject to harmonics than a thinner barrel which makes getting a good load much easier. OTOH, I could just be full of beans and lucky with this gun but I've been shooting it since 2007 (gift to myself when Nancy Pelosi became Speaker of the House) and have tested a lot of loads with it. With SMK or Hornady V-Max it will shoot 100 yard bug holes with no special handling of cases. Most of my brass is surplus LC. I don't mix commercial and military lots but I don't sort the LC either. Another opinion: You need a fairly high power scope for any realistic accuracy testing. A 3-9x40 won't do it.

David

[Oreo]

Got a 2.5x-16x50 Bushnell. And I've got both Hornady 55gr fmjbt, and 77gr SMK. TAC, and H335. Lots of TAC so I'm hoping I can find "the" load with that. I'm shooting a 20" stainless Lothar Walthar heavy barrel (not bull barrel), wylde chamber.

I started working up loads for it but had a couple kids and hardly have had time to shoot at all in the last few years. Now I'm getting a little free time again and trying to finish what I started working up loads. When I started I was getting 4" @ 100yds, but I couldn't hold the rifle steady on a bench that doesn't fit me and back then I had garbage walmart sand bags for a rest. Now I've got a Caldwell Rock rest, a good rear bag, and I'll still have to figure something out with those stupid cement benches. But I intend to get this rifle figured out by spring time.