223 case weight spread

just cull the outliers after you fire a group with them included. see if culling shrinks your group. then you can decide if culling is worth it.

luck

murf

What does weighing brass tell you? You don't know where the minuscule weight difference is. It may be a slightly thicker web, slightly thinner case rim, a small difference in the extractor groove or any number of other things. Shoot the brass and see if you can tell the difference before you throw good brass away.

Fred

Brass weight can be all over the place but it's the internal volume and consistent neck tension that matters. If you have a crony, run them all through with the same charge then compare. Will help you decide if it's really worth the effort. Since your eliminating the Very good Lapua Brass that is know for consistency, your going to have to do some work to find a good set. Lapua brass will get you 10+ firings before the primer pockets get start getting loose if your at or near max loads.

Contra the magical thinking going on above, case weight variation translates directly into case volume variation. Whether or not the difference in case volume matters to you depends on you.

I find that annealing necks for consistent tension and setting COAL for the individual rifle has much more effect on group size than the variation in volume within a batch of iso-year LC brass. You should do your own experiment to see if you can tell the difference.

that's a 5 grain spread over 10 cases. does that seem like it should matter?

Click to expand...

Excellent question. I would sort all your brass, take 10 that weigh the same and 10 from the very heaviest to the lightest, so you have the entire range. Load them all identical and go shoot two 10 shot groups. That will tell you if it’s worth it the next time. Oh, and report back your results.

greyling22 said:

I was about to load up some ammo for my bolt gun, and I thought, why not try to check case weights? So I took my box of sized and trimmed hornady 223 brass and weighed them. (all my brass is range pickup)
93.7
95.4
93.7
92.9
93.4
91.8
91.0
91.7
90.0
91.8
that's a 5 grain spread over 10 cases. does that seem like it should matter? is hornady brass just not very good? if I cull the 90 and the 95.4 I get a much closer spread. perhaps that is what I should do?
It's all hornady, but not from the same lot.

is there a better brand? I'm not going to buy lapua, and I'm not going to fool with the crimped primer pockets of lake city. who's left? winchester? pmc? remington?

I had read this article a while back https://www.6mmbr.com/223Rem.html that indicated hornady was the most consistent of the american brass, but my results are not backing that up.

Click to expand...

Lake City? I just paid 63 bucks or so per 500....That's new, not once fired so no crimps...haven't weighed them or loaded any yet.

Russellc

It matters. If you were to measure the internal capacity of the cases, the heavier ones might be 1/2 grain to 1 grain "less" case capacity than the lighter ones "generally". But weight alone does not dictate case capacity, there are other factors. Many people sort to be within "1" grain lots. So you would group all the say 94.0 to 95.0 and make that in a lot, etc. you will get better results than putting say 92.0 - 97.0 weights in same lot. I have not done this test yet with 5.56, but I have many times with 9 MM. Here is the results.

http://www.natoreloading.com/mixed/

or look at this pic...

http://www.natoreloading.com/mixed/assets/ab899fa8-7d0f-41bd-ba60-6db73fd5fb68

edwardware said:

Contra the magical thinking going on above, case weight variation translates directly into case volume variation. Whether or not the difference in case volume matters to you depends on you.

Click to expand...

It absolutely does not directly correlate , not even close .

I just measured the internal capacity of several thousand 5.56 cases over the last year. There is a correlation with the Nammo brass at least. However, it is not a 100% correlation. I would say its like 80% perhaps, or something like that. Its high.

If you were to measure the internal capacity of the cases, the heavier ones might be 1/2 grain to 1 grain more case capacity than the lighter ones "generally".

Click to expand...

I would have expected the opposite. I would expect the heavier cases, assuming the same external dimensions, to have less internal volume because they contain more brass than air inside.

If weight matters that much . It would mean head stamp doesn’t and you can just separate by weight regardless of headstamp. None of us believe that so why do any of us think separating by weight really matters .

I to have done quite a bit of case weight to case capacity testing . Admittedly that is with 308 more then 223 . I’ve found unless the case weight is 5+ gr in 233 and 10+gr in 308 there is no reliable correlation to weight vs capacity.

Even the same headstamp can be quite a bit different but that is likely do to different runs/lots of brass or drawn out on different machines. This is likely the issue with the OP and his same headstamp range pick up . They may all be the same headstamp but they were not manufactured on the same date with the same machine .

That’s one of the good things about Lapua brass . It comes with lot numbers and when buying more then 100 pieces . You can get all drawn from the same lot .

Metal God said:

It absolutely does not directly correlate , not even close .

Click to expand...

That is most fascinating. Please do tell what phenomena causes a case to be lighter, that does not also cause it to be larger (in volume) after conforming it to the inside of the same rifle chamber.

Will the OP be able to see or tell the difference after load such cases. Are you going to weigh all the bullets? What rifle, how far are you shooting, what is the end goal. Will you win prizes and money?
How accurate are you as a shooter. Does it matter??

Plus you are weighing brass from all different lot numbers and random range pick up. How many times has that brass be loaded.?

Buy some NEW brass size and trim that and see what you got.

Too much is made of case weight/bullet weight/ect. Distance is the tell tale and you have to start reaching out there to be able to tell the difference. By out there I'm talking over 600yds. Years ago we'd buy 1000 pieces of lc brass and size/trim/do the flash holes and work up loads for the new service rifle season. The ar's would be scoped and loads would be tested on calm days until a load was found that could hold the x-ring (short line/300yds 3" x-ring, back fence/600yd 6" x-ring). Never did do any weight sorting of the brass. Typically we'd do 3 reloadings of the brass and then toss it.

A couple years ago I decided to do a little experimenting/testing. I swage my own 223rem bullets from free range lead for cores and 22lr cases for jackets.


There's always 223rem cases laying around on the ranges so I thought it might be a good idea to do a little testing with the free brass/free bullet combo. I decided to spend a lot of money of a new rifle to use as a test bed. I ended up buying a nib heavy bbl'd savage axis for $318 out the door. It had a $50 mail in rebate and I sold the scope/ring combo that came with it for another $50. The end result was I had $218 in my "test" rifle. I did put a sightron 24x target dot scope on it that I typically use for silhouettes.

The free range pickup brass was sorted into piles, commercial & nato. The brass was cleaned/fl sized & trimmed to length and the primer pockets checked for crimp on the nato brass. I decided to use bl-c2 for my powder choice. It has always produced moa accuracy with 52gr to 62gr bullets in every 223rem I've ever owned. So I took the 223 axis out and punched the bbl out, set the torques on the hold down screws and started shooting/zeroing the scope in.

At the end of the day I took a rifle I had $218 in, used home made bullets from free lead/22lr cases. Used free range pick-up mixed nato cases and shot this target after having a 60-round bbl break-in period with the new rifle.



They are only 5-shot groups but that 25.5gr load has 3 bullets in the same hole & 2 out and measured 7/8" outside to outside. I like that plinking load enough that I load every junk nato case with it and use it in that axis.

Anyway those nato cases weren't weight sorted, headstamp sorted, sorted by year, nada. Simply inspected for defects and were marked for scrap if the primer pockets were loose.

Sorry fellas, I misstated on accident. Heavier cases generally have less capacity. I have this graph coming out for 5.56. But for 9 MM, you can see the proof here.

http://www.natoreloading.com/mixed/assets/51bb1304-1e68-4460-9dc3-a0a40315575f

Using mixed brass for 223/5.56 and shooting at distance without at least weight sorting, will not yield best results. That doesn't mean the results won't be acceptable, it just means you can do better. you can do way better. I have not put that study up yet, but I have already done it.
5.56 cases that have a capacity of 30.5 for example, have different FPS significant, than cases with 29.5.

Check out the standard deviations of these SPHERICAL powders using the "like" cases method.

This is like an average SD of about ~7. Using ball/spherical powder? With some 5 round groups having SD of 2? The extreme spread is almost nothing. If you use mixed cases and Alliant Varmint Powder, you will get extreme spreads of near 10x that amount, and at 600 yards, that is a miss by several inches. If I did not use almost the exact internal case capacity for all these loads, SD for these ball powders would be up near 20 on average and that is if I just weight and sort the cases. With mixed brass, SD will be up in the ~30 range.

http://www.natoreloading.com/varmint/assets/377cfdbf-2d1b-4897-8359-aff67302b064

When shooting at range, it starts to matter past 200 yards, SD/ES matter a lot.

It took me almost a year, sorting through near 10k brand new brass and measuring internal capacity of many thousands, to get almost "same" lots to do this testing. Internal case capacity "similar" is one of the most important parts in accuracy. Look at it like this. Different case capacities is literally the same result as shooting 1 lot with 25 grains of powder and 2.255 OAL, and another lot with 24.6 grains of powder. The longer range you go out, the more the 24.6 is going to drop. Same thing if you have case capacities way off.

I will argue though, and say clearly, that if your hunting, and your under ~200 yards. Mixed brass is TOTALLY acceptable accuracy near 1 MOA, just fine because the bullet drop is not enough to make it matter for that objective.

Forrest r, Very interesting stuff! I've never spent that sort of time and effort on testing .223. Certainly have not made bullets from .22 brass, although I've been aware of the process. And I've never tried bl-c2. Thanks for posting!

edwardware said:

That is most fascinating. Please do tell what phenomena causes a case to be lighter, that does not also cause it to be larger (in volume) after conforming it to the inside of the same rifle chamber.

Click to expand...

See ReloaderFreds post above or here below

ReloaderFred said:

What does weighing brass tell you? You don't know where the minuscule weight difference is. It may be a slightly thicker web, slightly thinner case rim, a small difference in the extractor groove or any number of other things. Shoot the brass and see if you can tell the difference before you throw good brass away.

Click to expand...

I'll add that all brass has tolerances so there can be very different shapes to the rim thickness , extractor grooves , shape/angle of the cuts of the extractor groove not to mention some brass is 70% -30% while others are 80%-20% and all those pieces will be with in SAAMI spec . Any one of those things can cause weight variances while doing nothing to case volume . Now lets stack all those variables together and add in different lots and machines producing each lot . There are SO many variables to case weight differences that will not change case volume it's a bit mind blowing .

Now that I've showed you mine , maybe you can show me yours ?

https://www.6mmbr.com/223Rem.html

From the link above , can you explain how the PMP case can weigh 11gr more then the Lapua ( new lot) case and yet there internal case volume is only 2 tenths of a grain different ? You can look through the whole list to see the case weight to case volume direct correlation theory completely destroyed . but please do tell how you explain the that phenomena ?

Metal God, there is also 1 severe flaw with that 6mmbr data. It fails to account for the extreme spread of cases. Those might be averages based on measuring 5 cases for all we know. The Extreme spread of case capacity between the SAME LOT of brass can be 1.5 grains of water. That spread covers almost EVERY brand on that list! you see?

By posting that picture, from 6mmbr, you prove even more there is a correlation? a very strong one, even with different brand brass.

I was talking about the same brand of brass, but that list proves there is a correlation irregardless of brand.

3 lightest cases on that list = TOP 4 highest in list case capacity. That is mega strong correlation.
2 heaviest cases on that list = BOTTOM 3 in list lowest case capacity. That is MEGA strong correlation.

IT does not have to be 1 to 1 correlation to be a correlation. It can be 50% to be true, 40%, 80%. But that list, you can present data that way, since those might be averages. That means nothing.

NATO Reloading said:

there is also 1 severe flaw with that 6mmbr data. It fails to account for the extreme spread of cases. Those might be averages based on measuring 5 cases for all we know.

Click to expand...

I always like when guys say stuff like that . Why ? because the opposite is also true so why say it unless you know what is what . So I'll say those "could" be the averages of 1,000 cases we just don't know haha

NATO Reloading said:

IT does not have to be 1 to 1 correlation to be a correlation.

Click to expand...

Yes it does or damn close to it for this conversation or it's not direct correlation . I even said the case weight at 5gr for 223 and 10gr for 308 is where you start to see a direct correlation . If you are separating your 223 cases by 1 or 2gr increments you are wasting your time period . There is NO direct correlation from case weight to case volume period .

Pretty old thread at this point but I can add a little to things. While I haven't gotten to doing this with 223 Remington I have done a little science experiment with 308 Winchester using five different samples of manufacture and ten cases in each group. The commercial brass was just that, commercial brass so not much can be said about it. The GI brass is LC 13 and WCC 10. Here is what the numbers look like and the groups of ten were just randomly picked. I had some new Lapua but didn't include it.



I weighed the cases. Then each case was filled with water and weighed again. The Tare weights were a small chunk of modeling clay used to plug the primer holes. All the brass was deprimed, sized and trimmed identically. The case empty and water filled weights were calculated and the weight differences listed. The weight differences were converted to case volume expressed in cc. Now my thinking and only my thinking which is open to being flawed is that when water testing all the brass needs to be sized and trimmed identically. I measured each resized case using an RCBS Precision Case Mic just to make sure they were sized uniform (actually 1.630" case head to shoulder datum) and my caliper for COAL. The case mic was tested against a chamber headspace gauge. That was as good as it gets for me.

So the question now becomes how much will it really matter? Given an identical powder charge how much will these numbers matter? I did this last year and am still looking at the 50 cases which I have primed with CCI BR 2 Large Rifle primers and all were hand primed. I plan to load them using AA 2495 but haven't determined how much powder and using Sierra 150 grain match king bullets. All loaded to an identical OAL. I will run them over my chronograph and old Oehler 35P. Other things have kept me occupied so this science experiment just sits. I will calculate the VMD for the powder I load and see what I get. I like about 44 grains of AA 2495 in my bolt gun so we will see how this all plays out.

Anyway I fall into the group who says case weight does not really tell the whole story as to case volume and what I want is uniform case volume or as close as I can get anyway. I wish I had the opportunity to finish this experiment and have some velocities but right now it has to wait.

Ron

Hi Ron, the answer is, the same grain variance in case capacity matters "less" the more case capacity you have. 2 grains in 308 matters near HALF what it does in 223. etc.

NATO Reloading said:

Hi Ron, the answer is, the same grain variance in case capacity matters "less" the more case capacity you have. 2 grains in 308 matters near HALF what it does in 223. etc.

Click to expand...

Oh absolutely, without a doubt. I am with you on that note. What I am wondering is within a caliber, for example the numbers I tossed out there, for a given load how much will those variances matter? Just plain sucks I am this far along and waiting for an opportunity to finish this damn little science experiment.

Ron

Here is a case volume test I did comparing fireformed to FL sized and if one way is better then the other to measure case volume . There is one calculation added wrong by a small amount If I recall but don't remember which one



I have a bunch more notes on this stuff but I'm in the middle of relocating my reloading room so It's not all readily available to me at the moment .