.222 from .223/5.56 Headsup

Ran into something I thought might benefit someone who is interested in saving some money on brass for their .222. I had collected several thousand pieces of .223/ 5.56 brass before acquiring a Rem 788 chambered for the .222 Rem. and decided to form cases using the range pickup brass. I trimmed cases and used a form/ trim die to set the shoulders back and used a primer pocket swage on the crimped primer pockets of the military brass. What I failed to do was weigh sort the cases to check for varying volumes. This was a serious mistake! I ruptured a case while using the rifle to shoot prairie dogs in Colorado and was unable to remove the damaged/expanded case head from the bolt face until I got back home. Put the rifle out of action for the remainder of the hunt and upon removing the case I found the extractor had been damaged from the expanded case rim. I started weighing unprimed cases and found the weights of cases varied from 89 grains to 100 grains! Avoid problems by weigh sorting your converted brass and benefit from my stupidity.

Yep, BTDT!

Same caveat when forming .300BO FROM 5.56x45.

You should also neck-turn your .222/.223 and anneal them. Worked great in my CZ552 .222 until my order of 100 PPU .222 came in the mail from Grafs.
Not worth the trouble considering how good and inexpensive the PPU cases are.
Ditto .300BO. I’ve discarded all my reformed .300 brass as I was gifted 500+ Hornady and Remington once fired cases.

yea. being you,re necking them down, the brass will be thicker and might not expand as readily upon firing to release the bullet.. to check this you can take a fired case and see if an unfired bullet will slip easily into the case, if not then you will need to either ream or turn the neck on them.. also the 5.56 brass has a slightly lower internal capacity then civilian .222 brass and you will need to reformulate the loadings accordingly or risk high pressures..

The neck thickness was no problem when I made up a bunch of 222s for my contender. With loaded bullets, there was still some freeplay between the case and chamber. When I made the 222s, it was using all the same headstamp (RWS as I recall) so I was not worried about weight variations.

However, the mesage that weight variation from range pick up 5.56 can be a big deal is very real.

With other cases where I started with range pickup 5.56, I have done a pre-sort by weight before I started. At first I was hoping to find reasonable consistency, but it quickly turned into culling a big fraction that was not even close.

http://www.6mmbr.com/223rem.html

Regarding brass weight... I bought a variety of cheap commercial .223 and 5.56 ammo several years ago to shoot in ARs. I weighed some empty cases. Of course, they all varied in weight. One brand, however, IMI, was much heavier than everything else. I don't recall the numbers now, but it probably wouldn't be a good idea to mix this in with everything else.

What kind of scale are you shooters weighing you brass on? Where would I get one?
I have reformed about 500-600 and have not had any issues.....and I don't want any!

So the heavier brass would use less powder? Or what causes the issue of mixing the different brass?

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Originally Posted by Mach_Cat

So the heavier brass would use less powder? Or what causes the issue of mixing the different brass?

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Heavier brass indicates reduced interior capacity which will result in higher pressures from similar charges.

I would be cautious about blaming a blown case on 11 grains difference in weight.
Compare brass specific gravity to powder specific gravity.

Brass is 8X times the density of powder therefore brass only takes up 1/8 the volume of the equivalent weight of powder.
11 grains of brass would take up about the same volume of 1.5 grains of powder. If you blew a case head over that small volume you either over charged a case or your loads were all too hot.

CBC brass that I had recently weighed well in excess of 100 grains. I didn't bother to check the water capacity, I just reduced the charges. This brass would have been higher pressure than any of the 92-93 grain LC brass just by comparing the primers with comparable fired loads. I separated it, loaded it reduced 1.5 grains, then tossed it.

Your Rem 788 probably still had the original factory barrel, but remember that 222 Rem was a bench rest cartridge for a number of years, any aftermarket barrel could have any one of a number of modified 222 variations with tighter necks, chambers, etc.

The same lists of acceptable brass for 300 Blackout to obtain .011" neck thickness is suitable for 222 Rem conversion. Sort and measure several pieces before starting to convert in quantity.

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Originally Posted by EDG

I would be cautious about blaming a blown case on 11 grains difference in weight.
Compare brass specific gravity to powder specific gravity.

Brass is 8X times the density of powder therefore brass only takes up 1/8 the volume of the equivalent weight of powder.
11 grains of brass would take up about the same volume of 1.5 grains of powder. If you blew a case head over that small volume you either over charged a case or your loads were all too hot.

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That is very insightful.

I sort cases for my .223/5.56 rifles for target/varmint ammunition but for blasting ammunition I run well below maximum to avoid the hassle. I like shooting sub MOA groups, but many times 2 MOA is good enough.

True here too. I load .223 well below 5.56X45 military velocity for blasting ammo. They still work the rifles just fine and hit the 100 and 200 yd. gongs with authority. 300 too for that matter!
When I make cases for 7.92X33/8Kurz from misc. military brass I find those cases to weigh around 25 grains more than Privi or FNM cases and reduce the load as needed to prevent excess pressure. That 25 grain difference due to less internal volume DOES make a difference for sure.
Pete

EDG - You are correct, the load was taken from a Lyman manual and was the max load for a 55 gr bullet w/ H335. I foolishly thought Lyman was conservative in there load recommendation due to the lower chamber pressures of the .222 in relation to the 5.56. I fired one round and the primer pocket was oversize when case was extracted. I just had to try the second round of that particular loading. Sadder but wiser, now. I did work thru the volume reduction due to increased mass of brass (cartridge brass s.g. is 8.53) and I saw the same thing you mentioned.