STICKY - Good/Bad brass list converting 5.56->300blk

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hcb
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Joined: Sun Jan 24, 2016 2:48 pm

Re: STICKY - Good/Bad brass list converting 5.56->300blk

Post by hcb »

+1 on GECO being bad brass to convert. Got one (I hope only one...I bought 1,000...jeez, I'm gonna have to watch closely) in my .223 batch I bought as once-fired. Cut down, sized, loaded. Neck size is 0.338", which is larger than the specification of 0.334" and of my Remington factory-load ammo. Other cases with various head stamps including FC, PAC, CBC, RP which I had also loaded, measured fine at 0.334" or less.

This cartridge jammed on feeding; it won't seat fully in the chamber and had to forcibly remove it. Placed a factory-load Remington cartridge right in after it, no problem, so not a problem with the chamber. Measured it, found the neck is too large. Pulled the bullet and found the neck wall thickness to be about 0.013 to 0.014". Checked two other cases which are head-stamped like the "good" cartridges I loaded and found their neck wall thickness to be in the 0.0105 to 0.011" range. A few thousandths here, a few thousandths there, and BOOM, NO FEEDY. :(

This "converting .223 Rem to 300 BLK" is certainly not without it's pitfalls. Good thing I didn't just load up a bunch and go hog hunting...or use it for PD.

--HC
Max713
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Re: STICKY - Good/Bad brass list converting 5.56->300blk

Post by Max713 »

I wanted to share a that I ran into some TAA marked brass tonight.
It's listed as good to go, but it consistently measured at .014-.015" for me...

Also Frontier is listed as a no go, but all the pieces I ran into measured .011-.012".

PPU on the other hand, like everyone else has reported is running between .015-.016".
BallisticTools
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Re: STICKY - Good/Bad brass list converting 5.56->300blk

Post by BallisticTools »

Max713 wrote:I wanted to share a that I ran into some TAA marked brass tonight.
It's listed as good to go, but it consistently measured at .014-.015" for me...
TAA is a sticky issue. There is some of it floating around with thicker walls, but a lot of it is only a little thicker like 0.012 - 13.
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BallisticTools
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Re: STICKY - Good/Bad brass list converting 5.56->300blk

Post by BallisticTools »

crossroader wrote:Major problem I found was that while forming brass was the development of the hated internal brass ring at the juncture of neck and shoulder, If loading shallow seated boat-tails it is not as noticeable, but when seating flat-base it becomes a problem with chambering. Inside neck reaming of this small amount is simple do to the amount is so slight. I found that using the appropriate sized and champhered four flute end mill, or drill bit this area can be cleaned up in a finger held process. This solved my head scrathing and takes no more time than brushing the inside of the neck.
I wrote an article that has a section on the "donut". In the article I mention that one way to avoid it is to use a roughing die like the GSI. It seems to help to form in two stages.
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Matteo674
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Re: STICKY - Good/Bad brass list converting 5.56->300blk

Post by Matteo674 »

You can add Romanian SADU 5.56 brass to the bad list. Necks are coming in at 0.014 -0.015".
Goesfaster71
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Joined: Tue Aug 23, 2016 7:40 pm

Re: STICKY - Good/Bad brass list converting 5.56->300blk

Post by Goesfaster71 »

Thanks for this info. I am so fortunate to be able to benefit from what you guys learned the hard way.
Goesfaster71
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Re: STICKY - Good/Bad brass list converting 5.56->300blk

Post by Goesfaster71 »

Thanks for this info. I am so fortunate to be able to benefit from what you guys learned the hard way.
faylo
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Joined: Wed Aug 03, 2016 10:56 pm

Re: STICKY - Good/Bad brass list converting 5.56->300blk

Post by faylo »

I'd like to add a good brass headstamp marked M193. There is also a B O or 8 0 opposite of the M193. I believe it is Centurion made. I bought a batch of 1000 5.56 back in '09 and have converted 50+ and they all worked. Neck thickness is measuring right at .011-.012 which is right in line with the converted LC brass I picked up from gibrass.com.
-Jim
hardway
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Joined: Tue Sep 13, 2016 9:14 pm

Re: STICKY - Good/Bad brass list converting 5.56->300blk

Post by hardway »

New to the board so pardon any foulups in posting.
I was given some ".223" brass but I'm unable to resize. I checked the necks and they vary anywhere from .014 to .018. The head stamps are:
12:00 W
2:00 C
5:00 C
7:00 6
10:00 6

12:00 86
6:00 13


Some of the primers are staked & some are not. I'll probably just recycle these.
oldtoys1961
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Re: STICKY - Good/Bad brass list converting 5.56->300blk

Post by oldtoys1961 »

L2A2---I've run across this stuff a good bit. Its thick. I haven't gauged it but I can tell when I get one in the cutting batch. I toss it.
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