223 case questions.

5.56 and .223 chambers are exactly the same. The only difference is forward of the chamber proper, in the throat, where the 5.56 has a slightly longer leade into the rifling.

The deformed brass is not deformed. It's a different caliber, likely 7x45 Ingram.

50of4064 said:

my guess, the 556 was shot in a 223 chamber.

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Nope, that certainly would not have caused it.

It is probably a wildcat and someone will be along shortly to identify it. That's my guess.

Looks like a 7mm ""Ingram" or 7mm TCU

The 7x45 Ingram is based on a 223 case necked up to 7mm with a 45° shoulder and less body taper than its parent cartridge case. This cartridge is very similar to the 7mm TCU, significantly differing only in shoulder angle. The 7x45mm has a 45° angle (as opposed to the 40° shoulder angle of the 7mm TCU cartridge) and therefore requires extra care in seating bullets to prevent shoulders from collapsing. This cartridge is quite efficient. It provides good velocity from a short barrel with

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https://press.hornady.com/assets/site/hornady/files/obsolete-data/7x45-ingram.pdf

It feels redundant to review this again, but:

I find a lot of 223 stamps on 300AAC cases (from reformed cases), and I make it too. I have a decent amount of 8mauser marked "30-06" and lots of 9mm Para stamped cases that are actually 9x18. I know every manual says something along "use only ammunition marked on barrel". One of many reasons not to shoot other peoples reloads. FYI if you want to you can make 45 ACP from 06, and .380 ACP from 223 as well.

I edited this post for clarity, but the point remains, even a perfectly safe, properly loaded round of 38-44, 300 AAC, .270, or dozens of others can break parts, or worse if someone reads the stamp, and goes from there. Many shooters would not notice a difference by look/feel.

mjsdwash said:

I find a lot of 223 marked 300AAC. . ..

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Now THAT would be remarkable.

I load for several cartridges that the parent case does not look like the finished case regardless what the stamp on the case head says.

Here are some of the cases that I form for firearms that I shoot...
38/45 Clerke from 45 ACP
7mm International Rimmed from 30-30 Winchester
22x6.5 from 6.5 SPC
300 Blackout from 223 Remington
22 Benchrest from 6mm Benchrest
221 Remington Fireball from 222 Remington (fortunately, here, factory 221 Rem Fireball cases are still available but...)
6.5 Kurz Mauser from 7x57 Mauser

There are thick books listing wildcat and obsolete cartridges and how to make them from existing cartridges.

50of4064, file this in the "learn something new everyday" category.

mjsdwash said:

I find a lot of 223 marked 300AAC, and make it too. I have a decent amount of 8mauser marked "30-06" and lots of 9mm Para that are actually 9x18. I know every manual says something along "use only ammunition marked on barrel". One of many reasons not to shoot other peoples reloads. FYI if you want to you can make 45 ACP from 06, and .380 ACP from 223 as well.

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I've never see a .223 case marked 300 ACC. I have seen a lot of cases marked .223 that are actually 300 ACC though.

Nor have I ever seen 9x19 para marked brass that's 9x18. 9x18 is Makarov brass. BTW, 9x18 won't chamber in a 9x19 chamber as the bullet is .365.

Texas10mm said:

I've never see a .223 case marked 300 ACC. I have seen a lot of cases marked .223 that are actually 300 ACC though.

Nor have I ever seen 9x19 para marked brass that's 9x18. 9x18 is Makarov brass. BTW, 9x18 won't chamber in a 9x19 chamber as the bullet is .365.

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read as "223 case marked" 300 AAC, with case mark being the stamping, not case, marked.

mjsdwash said:

read as "223 case marked" 300 AAC, with case mark being the stamping, not case, marked.

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I know. I've never seen a 223 case that has a 300 Blackout headstamp. English is tricky.

I find a lot of 223 marked 300AAC

This is read as you find a lot of 223 that's marked 300ACC.

Texas10mm said:

I know. I've never seen a 223 case that has a 300 Blackout headstamp. English is tricky.

I find a lot of 223 marked 300AAC

This is read as you find a lot of 223 that's marked 300ACC.

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yea, had I proof read that I would have caught it too. Once pointed out it really shines. Its more than a grammar issue here to, since we are talking about potentially turning rifles into bombs if misread. I think i'll clean it up.

50of4064 said:

If you can shed some light on this for me, please leave your thoughts.

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Since fired cartridge brass has conformed to the chamber of the firearm before the pressure reduces and the brass shrinks and is extracted, the brass is very close to the chamber of the firearm that it was fired out of. Since 7mm is .284", I would think that the person with the .284-223 wildcat (whichever one it may be) sized and loaded up mixed brass using 223 as the donor cartridge. They fired them at the range, and left the cases. OP found the sized cases that were headstamped 223 but were obviously not.

Necking cases up and down doesn't happen as often since we have incredible access today to brass manufacturers. But, it is a good reminder to check pick up brass before or as you reload it since the shoulder and neck may not match the headstamp!

50of4064 said:

Thank you all for the interest and wisdom, .....
now to find a home for these 165 cases...free! Just pay shipping.

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You may not find a home because if someone went through the effort to form them and leave behind they may be done or have issues. I would just recycle them.