CBC casings

I was on a different form and a very similar question was asked involving the CBC cases . In That thread several posters remarked on several different cartridges that CBC makes brass for seem to cause issues . My experience with these cases is mostly with 223 brass and it was significantly thicker than most commercial brass if not all . It resulted in the powder almost overflowing out of the case due to less case volume and produced 100 ft./s faster velocities compared to other cases using the same charge . This thread and that other thread leads me to believe that CBC cases are simply just thicker walled cases resulting in all kinds of problems .
 
It's the hardest 9mm brass I have
Click to expand...

This is my/our dilemma . Is it harder brass or is it thicker walled brass which makes it seem harder ? One is no big deal the other reduces case volume which increases pressure at same charge weights using just about any other brass .
 
Case wall thickness and case weight match my Blazer brass, but the CBC is noticeably harder, you can feel it when you seat a bullet.
If you load CBC and Blazer with the same bullets and die settings, the CBC rounds end up a consistent .010" longer than the Blazer rounds.
I had to drop my Lee seating die, it just wasn't working with CBC brass and XTP/HAP bullets. Went to a comp seater and now I don't have to worry about my brass. Accuracy was instantly improved too.
 
Get a scale, an eye dropper and a glass of water and measure the volume. You won't have to guess.
Click to expand...

Already did it with those 223/5.56 CBC cases I referenced earlier and they had less case volume . I found out when loading some mixed brass and is why I did the H2o test on the CBC cases . I forget the exact charge I was loading at the time but for the sake of this discussion lets say 25gr of 4320 in my LC cases and all others in the mixed lot filled the cases to the neck/shoulder junction but that same charge in CBC cases almost overflowed the case mouth . I'm not going to go into great detail because I've posted this several times over the years here in multiple threads but .... I went ahead and seated 55gr bullets into those completely full CBC cases and fired them over a chrono . They averaged 98fps faster then the same charge and bullet in LC cases .

As for case wall thickness . I did not measure the case mouth wall thickness of the CBC cases . Regardless the lower case volume came from somewhere . Even if the necks were the same thickness , somewhere down the case body or even the internal top of the case base clearly reduced case volume . I never sectioned any of them to see where the difference was but it was there somewhere . As for 9mm cases and the OP . I'd think you'd get bulging for one of two reasons or both I guess . That is thicker cases or larger diameter bullets . If the same bullet does not bulge most other cases then the cases them selves likely have thicker walls . If the bullet is bulging most headstamps then the bullet is likely a tad oversized . Although not the same I see this all the time loading for rifles . My same .308 bullets make my finished LC case necks way fatter then when loaded in Win cases . If the bullets are the same diameter and your finished cartridge in one case is larger in diameter then then another case . It's not the bullets making it fatter .
 
Last edited:
Well, Poop!

I guess 45acp brass by CBC is better than 357 magnum brass.
I loaded some test rounds with Norma brass, and everything was normal.
Then yesterday I loaded some with CBC brass, and the experience was eye-opening.
Cases felt brittle going thru the sizer, primers went in suddenly and loosely, and the neck tension wasn't what I am used to.
They crimped okay, but that was all.
I am going to pull them apart to salvage the bullets, primers, and powder, then throw the cases in the scrap barrel.
I'm glad I stopped after 5 rounds in a row all felt bad.
Fortunately I have plenty of Norma, and some over-priced Starline on the way. I paid the crazy price of 70 cents each with shipping for them.
(Yeah, I WANTED them.):rolleyes:
 
No. That was for 357 brass, and Starline has been out for a long time.
They say 'no backorders at this time'.
It took me hours to find this crazy deal, but I am stocked up for quite a while.
 
You must log in or register to reply here.
Back
Top