.223/5.56 brass for 300 BLK
Posted: Thu Jun 21, 2012 4:31 pm
Hello . I got this answer from one of the major reloading supply vendors when I asked about what dies I would need to resize .223 or 5.56 brass for the 300 Blk .. Anyone else ever heard of this problem??
Should you choose to make 300 AAC Blackout cases from 223 Remington or 5.56 cases, you may have to ream the case necks to obtain a maximum loaded case neck outside diameter of .3340". The reason for this is that the case wall thickness of a rifle case is tapered, being thinnest at the case neck and thicker towards the case head. When you trim the longer case to the shorter dimension, you are getting into a thicker case wall. The maximum allowable case neck wall thickness is .013" when seating a .308" bullet. Because of the taper of the case, wall thickness at the case neck mouth may be .013" but could be thicker just above the shoulder. The thicker wall in this area will cause the loaded case neck outside diameter to be in excess of .3340". This will cause the bullet to be pinched by the case when the round is chambered, which may result in dangerously high chamber pressures.
I have been thinking of building a 300 blackout and would like to know about reloading .223 brass for it ... Thanks , Don J.
Should you choose to make 300 AAC Blackout cases from 223 Remington or 5.56 cases, you may have to ream the case necks to obtain a maximum loaded case neck outside diameter of .3340". The reason for this is that the case wall thickness of a rifle case is tapered, being thinnest at the case neck and thicker towards the case head. When you trim the longer case to the shorter dimension, you are getting into a thicker case wall. The maximum allowable case neck wall thickness is .013" when seating a .308" bullet. Because of the taper of the case, wall thickness at the case neck mouth may be .013" but could be thicker just above the shoulder. The thicker wall in this area will cause the loaded case neck outside diameter to be in excess of .3340". This will cause the bullet to be pinched by the case when the round is chambered, which may result in dangerously high chamber pressures.
I have been thinking of building a 300 blackout and would like to know about reloading .223 brass for it ... Thanks , Don J.