This peaked my curiosity. What kind of accuracy/consistency would 223 get while being fired from a 300blk rifle. I know you can fire form 300blk brass using 223 ammo but that seems like a waste of a good 223 round.
So how crappy would a grouping be?
Reason I ask is I'm considering switching my AR over to 300 but I have about 2000rnds of 223.... This might also just prompt me to buy a second rifle in 223.... But I'm still curious.
Anyone have any feedback?
This is incorrect. You can not fireform 300BLK from 223 in a rifle. You need to cut the 223 brass off at the shoulder just to get it to the correct length, then you form it in your sizing die, then trim to final length.
Even if you chambered a 223 round in a 300BLK rifle you would probably at minimum split the neck from it expanding so much. Chances are also very good that you wouldn't get enough pressure to cycle a semi auto rifle due to the bullet forming no seal to the barrel. I think you would get shotgun patterns, ruined brass, and a lot of fouling from the powder not burning properly due to the lack of pressure.
I would not try to do this at all.
Retract previous statement... We're all on same page....
But I have heard and seen people fire form 300 brass out of 223....
They are liars and no you haven't seen that because it wouldn't work like that.
What happened to the 1/4 inch of brass that needs to be cut off during the process?
300BLK is a great cartridge but there really are no shortcuts to making the brass other than buying bigger equipment to make it go faster. I bought myself a 6 inch chop saw and the RCBS case prep center to make things easier. One way or another you need to cut the brass down then debur it before running it through the sizing die then trim it to final length before loading it.
If you have specific plans for your 300BLK rifle be sure you understand the cartridges limitations before you get into it. This is not a 308win in a small package.
As much as I love the cartridge I see no advantage to running it over a 223 in an AR in Canada. Ammo is double the cost of 223 and sometimes more than double and the ballistics are not as flat as 223 so shooting longer distances is more difficult. It does have more hitting power but I don't think the piece of paper is going to notice. I own 2 non restricted 300BLK rifles and one AR in 300BLK and the AR doesn't get used much.
