observations of .223 brass

Panfisher · February 11, 2015, 12:57 AM

I have been working my way through 2k of .223/5.56 brass I bought as range pickup stuff. I have heard many times that the brass is essentially all the same and that its the load and chamber that is different. However especially as I trim them it becomes apparent that the are differences in length. The Hornady, FC, and some winchester don't quite make it to the cutter head on my Lyman trimmer, or at most get only shined by it, (all of them are stamped .223 Rem). Most of the military stuff and especially LC13 gets a very noticeable amount trimmed off, enough that I can recognize them as I lock them in the trimmer. I should be measuring a few just out curiosity I suppose. It is nearly all once fired, with the military stuff still having the primer crimps. Really doesn't affect my loading since once I am done trimming and primer pocket reaming they are the same as .223, and since I don't shoot anything heavier than 62 grains I don't think any internal capacity differences are going to affect me. Also noticed that the 4 star primer crimps are tougher to remove, but even they don't stand up to the Lyman reamer chucked in a drill press. The are a few things you notice when your meds keep.you up late into the night.

jrobin3360 · February 11, 2015, 05:48 AM

.223/5.56 brass cases are mainly the same on the outside. Inside the case may be a different story. I've noticed that 5.56 (Lake City, NATO, MilSpec) is somewhat thicker & that will usually mean inside volume is different than regular .223 brass. Like you, I don't shoot anything bigger than 63gr bullets, thought I mainly stick to 55gr so volume probably isn't a big deal.
I only trim my cases if the neck sticks up outside of my case gauge.
Crimped primer pockets are a PITA, having to sort thru them to exclude the
.223 from the 5.56 cases & since I use either a hand reamer or a countersink bit on my cordless drill. But no good brass goes unused.

griz · February 11, 2015, 08:00 AM

I don't understand the belief that pressures increases from changes in case capacity are less pronounced if the bullet weighs less. I shoot mostly 55 grains and can see the difference in velocity. By the way, sometimes commercial cases have less capacity than the 556, you have to measure to know.

Panfisher · February 11, 2015, 10:15 AM

I was more surprised at the variety of case lengths than anything else. Especially with the mil stuff. Of course with a 5.56 chamber and the longer leade the length is less of an issue I guess.

skizzums · February 11, 2015, 10:51 AM

Well if military cases are truly thicker, which most have observed here, then its understandable that it will need trimmed more if more brass is getting squeezed into the sizing die

Panfisher · February 11, 2015, 10:56 AM

Hmm interesting, I will try to remember to put the calipers to some tonight before I re-size them, both the hornady and FC's and the LC 13's and then again after resizing to see how much of a change. Finally something to break up the monotony of case prepping.

Gadawg88 · February 11, 2015, 11:51 AM

I have found that FC .223 brass rarely needs trimming. In fact most of it ends up short i.e. <1.75. The primer pockets also start to loosen up after about 3 loadings. I recently began culling all FC .223 brass because of the loose pockets. I am segregating it all. Most of it probably has another load in it, so I will keep it as reserve only. Just not worth the hassle and mess of a lost primer in my AR trigger group.

Jim243 · February 11, 2015, 12:29 PM

Quote:

I was more surprised at the variety of case lengths than anything else.

That will be dependent on the rifle's chamber it was shoot out of, more so than the manufacturer. While there is spring back in most metals, the size of the chamber and age of the barrel, it is in, will have an effect on whether the case will grow or shorten when fired. Yes, they can shorten when fired out of oversize chambers make to fire anything put into them (like machine guns) without jamming.

Jim

**Unclenick** · February 11, 2015, 12:39 PM

Quote:

Originally Posted by panfisher

I was more surprised at the variety of case lengths than anything else.

A lot of times once-fired .223 has come from a full-auto weapon. They tend to stretch the case.

Don't fret about case capacities. There is South African and old Lapua brass that is low in capacity. That is outlined in the table about 1/4 of the way down, here. They are also made from different alloys, as this analysis reveals. The final hardness, though, also depends on how many times the brass is annealed during forming and how far back in the process the last annealing was before the final shoulder forming, as this determines how much work hardening was involved.

Panfisher · February 11, 2015, 12:59 PM

It is consistend with the LC13 batch of brass, but it could well all have been fired from the same rifle. I think it came from a private range so unlikely it was from an MG, but it was in Texas so not out of the realm of possibility.

All in all it won't matter as they will all be back to length when I get through with them. Just a curiosity to me.

Jim243 · February 11, 2015, 01:06 PM

I trim and form all my 223/5.56 brass even it doesn't need it, just faster than trying to sort it out. Very seldom do I find a case that is too short though.

Good luck and stay safe.
Jim

skizzums · February 11, 2015, 01:41 PM

I tjought the op was meaning that all of this brass was fired from HIS rifle. But if its just range pick up, who knows then

Panfisher · February 11, 2015, 06:23 PM

The only thing I am sure of are they were not fired from my my rifle. Did a little measuring before supper. The LC 13 1.766 before sizing 1.770 after. LC 12, 1.762 before sizing as 1.767 after. Hornady 1.747 before sizing and 1.749 after. After trim they all be 1.750 except for the few that still are under slightly.

**Unclenick** · February 12, 2015, 02:35 PM

OK, now that I see your numbers there is another element to this I had brain gas about: For some reason, in 2001, SAAMI changed the case length tolerance on .223 Brass length from 1.760" -0.020" to 1.760"-0.030". The trim-to length manufacturers use will be the average, so it was 1.75". but is now 1.745" that they aim for. As far as I know, the military uses the same -0.015" case length tolerance they use on 30-06 and 7.62 NATO. So the military average length and, therefore, trim-to length, will be 1.7525", or 0.0075" longer than post-2001 manufacture SAAMI average cases.

I popped down to the basement with my calipers, where I still have a couple thousand new, never loaded LC cases, and measured the first two my fingers touched: 1.7525" and 1.7530". I didn't bother with any more, so it's not a scientifically significant sample, but neither do I have reason to expect to find others different. It's the expected average within the limits of the caliper's accuracy and resolution.

So, the LC brass is expected to be 7½ thousandths longer in the first place. Your Hornady was a couple thousandths shorter, taking us to 9½ thousandths difference. Add to this that 5.56 NATO minimum chambers are 0.004" longer at the shoulder than SAAMI minimum chambers, and setting the shoulder back funnels the brass into the narrower neck, so we have accounted for maybe 0.013" inch of difference before worrying about how much they stretched on firing. Add to this that 5.56 chambers are typically a couple thousandths wider at the head (for feed ease) and that the resulting extra width will be squeezed forward when an FL sizing die closes in on the sides of the cases. It could add 0.002"-0.005" pretty easily.

So, we seem to have accounted for most of the difference before thinking machine gun. Depending on the exact sizing die squeeze, perhaps all of it. Whatever we have failed to account for may be due to higher peak pressure. The military loads have to meet a tighter velocity window (±40 fps vs ±90 fps for SAAMI), plus meet a gas port pressure window, plus remain within the same peak pressure limit SAAMI uses, so you find military ammo is often closer to maximum pressure than commercial loads. As a result, even though the maximum pressures are the same, the military stuff sometimes runs a little hotter.

Bottom line, this is actually looking pretty normal and expected when everything is added up. You could check for pressure ring thinning in the longer cases because they've been stretched more, but as long as they've not been reloaded before, that's not likely to have occurred. Once they are sized and fired in your gun with the same loads, I think the discrepancies will all go away.

Panfisher · February 12, 2015, 07:17 PM

Wow thanks Uncle nick that's a good explanation. I was never worried about them just kept noticing the differences as I trim case after case etc. If I had a way to post a photo I would show one of the cases that was in the mix and see if anyonehas any clue how it ended up the way it is. It almost resembles a little weatherbycase, no shoulder left just two rounded edges, little body taper, and longer. Almost looks like it was fired in some other chamber than a .223/5.56. I kept it as a curiosity.

4runnerman · February 12, 2015, 09:52 PM

Internal case capacity is different. Very simple to see. Drop 25 gns into 5.56 and then into 223. Big difference. Most 223 ( deprimed and sized) will come in at 92 to 94 gns. where as 5.56 will come in at 96 to 112 gns. Now for plinking not a big deal. Shooting for accuracy- now you have a issue. Weigh your cases and pick all that are with in 2 or 3 gns of each other. Sell or throw the rest. I have also found case headstamp really does not make a big difference as long as the weight is very close.

jrobin3360 · February 13, 2015, 03:18 AM

I'm pleased to have kept up with this thread. Gleaned some insights I didn't either know about or think important (case weight is one).
I'm not a hunter but I do want my reloads to be as accurate as I can possibly make them & had no idea that case WEIGHT played a big part in that. I don't recall seeing that tidbit in any of my manuals.
I do sort by headstamp & try to keep separate those I have fired from those that haven't been prepped (I can usually pickup a good amount of range brass each trip is why I do this).

February 11, 2015, 12:57 AM	#1
Panfisher Senior Member Join Date: July 30, 2010 Location: Missouri Posts: 1,337	observations of .223 brass I have been working my way through 2k of .223/5.56 brass I bought as range pickup stuff. I have heard many times that the brass is essentially all the same and that its the load and chamber that is different. However especially as I trim them it becomes apparent that the are differences in length. The Hornady, FC, and some winchester don't quite make it to the cutter head on my Lyman trimmer, or at most get only shined by it, (all of them are stamped .223 Rem). Most of the military stuff and especially LC13 gets a very noticeable amount trimmed off, enough that I can recognize them as I lock them in the trimmer. I should be measuring a few just out curiosity I suppose. It is nearly all once fired, with the military stuff still having the primer crimps. Really doesn't affect my loading since once I am done trimming and primer pocket reaming they are the same as .223, and since I don't shoot anything heavier than 62 grains I don't think any internal capacity differences are going to affect me. Also noticed that the 4 star primer crimps are tougher to remove, but even they don't stand up to the Lyman reamer chucked in a drill press. The are a few things you notice when your meds keep.you up late into the night.

February 11, 2015, 10:51 AM	#5
skizzums Senior Member Join Date: July 1, 2013 Location: Douglasville, Ga Posts: 4,615	Well if military cases are truly thicker, which most have observed here, then its understandable that it will need trimmed more if more brass is getting squeezed into the sizing die __________________ My head is bloody, but unbowed

February 11, 2015, 01:06 PM	#11
Jim243 Senior Member Join Date: January 5, 2009 Location: Just off Route 66 Posts: 5,067	I trim and form all my 223/5.56 brass even it doesn't need it, just faster than trying to sort it out. Very seldom do I find a case that is too short though. Good luck and stay safe. Jim __________________ Si vis pacem, para bellum

February 11, 2015, 01:41 PM	#12
skizzums Senior Member Join Date: July 1, 2013 Location: Douglasville, Ga Posts: 4,615	I tjought the op was meaning that all of this brass was fired from HIS rifle. But if its just range pick up, who knows then __________________ My head is bloody, but unbowed

February 12, 2015, 02:35 PM	#14
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	A Different Explanation OK, now that I see your numbers there is another element to this I had brain gas about: For some reason, in 2001, SAAMI changed the case length tolerance on .223 Brass length from 1.760" -0.020" to 1.760"-0.030". The trim-to length manufacturers use will be the average, so it was 1.75". but is now 1.745" that they aim for. As far as I know, the military uses the same -0.015" case length tolerance they use on 30-06 and 7.62 NATO. So the military average length and, therefore, trim-to length, will be 1.7525", or 0.0075" longer than post-2001 manufacture SAAMI average cases. I popped down to the basement with my calipers, where I still have a couple thousand new, never loaded LC cases, and measured the first two my fingers touched: 1.7525" and 1.7530". I didn't bother with any more, so it's not a scientifically significant sample, but neither do I have reason to expect to find others different. It's the expected average within the limits of the caliper's accuracy and resolution. So, the LC brass is expected to be 7½ thousandths longer in the first place. Your Hornady was a couple thousandths shorter, taking us to 9½ thousandths difference. Add to this that 5.56 NATO minimum chambers are 0.004" longer at the shoulder than SAAMI minimum chambers, and setting the shoulder back funnels the brass into the narrower neck, so we have accounted for maybe 0.013" inch of difference before worrying about how much they stretched on firing. Add to this that 5.56 chambers are typically a couple thousandths wider at the head (for feed ease) and that the resulting extra width will be squeezed forward when an FL sizing die closes in on the sides of the cases. It could add 0.002"-0.005" pretty easily. So, we seem to have accounted for most of the difference before thinking machine gun. Depending on the exact sizing die squeeze, perhaps all of it. Whatever we have failed to account for may be due to higher peak pressure. The military loads have to meet a tighter velocity window (±40 fps vs ±90 fps for SAAMI), plus meet a gas port pressure window, plus remain within the same peak pressure limit SAAMI uses, so you find military ammo is often closer to maximum pressure than commercial loads. As a result, even though the maximum pressures are the same, the military stuff sometimes runs a little hotter. Bottom line, this is actually looking pretty normal and expected when everything is added up. You could check for pressure ring thinning in the longer cases because they've been stretched more, but as long as they've not been reloaded before, that's not likely to have occurred. Once they are sized and fired in your gun with the same loads, I think the discrepancies will all go away. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

February 11, 2015, 05:48 AM	#2
jrobin3360 Senior Member Join Date: June 30, 2013 Location: Kentucky, near Ft Knox Posts: 153	.223/5.56 brass cases are mainly the same on the outside. Inside the case may be a different story. I've noticed that 5.56 (Lake City, NATO, MilSpec) is somewhat thicker & that will usually mean inside volume is different than regular .223 brass. Like you, I don't shoot anything bigger than 63gr bullets, thought I mainly stick to 55gr so volume probably isn't a big deal. I only trim my cases if the neck sticks up outside of my case gauge. Crimped primer pockets are a PITA, having to sort thru them to exclude the .223 from the 5.56 cases & since I use either a hand reamer or a countersink bit on my cordless drill. But no good brass goes unused.

February 11, 2015, 08:00 AM	#3
griz Senior Member Join Date: July 31, 2000 Location: Middle Peninsula, VA Posts: 1,588	I don't understand the belief that pressures increases from changes in case capacity are less pronounced if the bullet weighs less. I shoot mostly 55 grains and can see the difference in velocity. By the way, sometimes commercial cases have less capacity than the 556, you have to measure to know.

February 11, 2015, 10:15 AM	#4
Panfisher Senior Member Join Date: July 30, 2010 Location: Missouri Posts: 1,337	I was more surprised at the variety of case lengths than anything else. Especially with the mil stuff. Of course with a 5.56 chamber and the longer leade the length is less of an issue I guess.

February 11, 2015, 10:56 AM	#6
Panfisher Senior Member Join Date: July 30, 2010 Location: Missouri Posts: 1,337	Hmm interesting, I will try to remember to put the calipers to some tonight before I re-size them, both the hornady and FC's and the LC 13's and then again after resizing to see how much of a change. Finally something to break up the monotony of case prepping.

February 11, 2015, 11:51 AM	#7
Gadawg88 Senior Member Join Date: March 2, 2013 Location: Georgia Posts: 241	I have found that FC .223 brass rarely needs trimming. In fact most of it ends up short i.e. <1.75. The primer pockets also start to loosen up after about 3 loadings. I recently began culling all FC .223 brass because of the loose pockets. I am segregating it all. Most of it probably has another load in it, so I will keep it as reserve only. Just not worth the hassle and mess of a lost primer in my AR trigger group.

February 11, 2015, 12:59 PM	#10
Panfisher Senior Member Join Date: July 30, 2010 Location: Missouri Posts: 1,337	It is consistend with the LC13 batch of brass, but it could well all have been fired from the same rifle. I think it came from a private range so unlikely it was from an MG, but it was in Texas so not out of the realm of possibility. All in all it won't matter as they will all be back to length when I get through with them. Just a curiosity to me.

February 11, 2015, 06:23 PM	#13
Panfisher Senior Member Join Date: July 30, 2010 Location: Missouri Posts: 1,337	The only thing I am sure of are they were not fired from my my rifle. Did a little measuring before supper. The LC 13 1.766 before sizing 1.770 after. LC 12, 1.762 before sizing as 1.767 after. Hornady 1.747 before sizing and 1.749 after. After trim they all be 1.750 except for the few that still are under slightly.

February 12, 2015, 07:17 PM	#15
Panfisher Senior Member Join Date: July 30, 2010 Location: Missouri Posts: 1,337	Wow thanks Uncle nick that's a good explanation. I was never worried about them just kept noticing the differences as I trim case after case etc. If I had a way to post a photo I would show one of the cases that was in the mix and see if anyonehas any clue how it ended up the way it is. It almost resembles a little weatherbycase, no shoulder left just two rounded edges, little body taper, and longer. Almost looks like it was fired in some other chamber than a .223/5.56. I kept it as a curiosity.

February 12, 2015, 09:52 PM	#16
4runnerman Senior Member Join Date: January 16, 2010 Location: Minnesota Posts: 3,577	Internal case capacity is different. Very simple to see. Drop 25 gns into 5.56 and then into 223. Big difference. Most 223 ( deprimed and sized) will come in at 92 to 94 gns. where as 5.56 will come in at 96 to 112 gns. Now for plinking not a big deal. Shooting for accuracy- now you have a issue. Weigh your cases and pick all that are with in 2 or 3 gns of each other. Sell or throw the rest. I have also found case headstamp really does not make a big difference as long as the weight is very close. __________________ NRA Certified RSO NwCP- Performance Isn't Optional

February 13, 2015, 03:18 AM	#17
jrobin3360 Senior Member Join Date: June 30, 2013 Location: Kentucky, near Ft Knox Posts: 153	I'm pleased to have kept up with this thread. Gleaned some insights I didn't either know about or think important (case weight is one). I'm not a hunter but I do want my reloads to be as accurate as I can possibly make them & had no idea that case WEIGHT played a big part in that. I don't recall seeing that tidbit in any of my manuals. I do sort by headstamp & try to keep separate those I have fired from those that haven't been prepped (I can usually pickup a good amount of range brass each trip is why I do this).