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Shrinking .223 brass???

NeoBlackdogNeoBlackdog Member Posts: 12,585 ✭✭✭✭
So I loaded up a bunch of .223. Did a full length resize with small base dies, trimmed the cases to 1.750", added powder, primers, bullets, all the usual stuff. I went out and shot a bunch of it a couple weeks ago and just discovered that the fired brass now measures 1.740"-1.745". This was fired from a DPMS 16" pencil barrel with no FTF or FTE issues, everything ran flawlessly. I thought the brass would stretch a little when fired???

Comments

  • dcs shootersdcs shooters Member Posts: 10,969
    edited November -1
    Was it new before firing [?] It might have formed to the chamber on the first firing [;)]
  • NeoBlackdogNeoBlackdog Member Posts: 12,585 ✭✭✭✭
    edited November -1
    quote:Originally posted by dcs shooters
    Was it new before firing [?] It might have formed to the chamber on the first firing [;)]


    All once fired and picked up off a police range. I trimmed all cases to 1.750". I have some from the same batch that didn't get loaded and it all measures 1.75". Weird, huh?
  • Tailgunner1954Tailgunner1954 Member Posts: 7,815
    edited November -1
    Measure your "short" brass after resizing, bet you'll gain back your length.
    The case gets fatter when fired, but the amount of brass remains the same, guess where the brass came from.
  • 243winxb243winxb Member Posts: 258 ✭✭
    edited November -1
    Tailgunner is correct. On firing, the brass expands outward to fill the chamber. The shoulder is pulled back. It take a full pressure maximum loading to get a case to fully fill the chamber. This is way so many reloaders get a false reading using a Wilson or Hornady type gage to measure head to datum (shoulder) of the fired brass.
    [url] https://saami.org [/url]
  • NeoBlackdogNeoBlackdog Member Posts: 12,585 ✭✭✭✭
    edited November -1
    Thanks TG & 243. I suppose that makes sense. The load I'm using is not particularly stout, but it is pretty accurate. 24.5 grains of H335 under a Berry's 55 grain plated bullet and CCI small rifle primers that gives me .75" groups a 100 yards from a 16" pencil barrel.
  • wanted manwanted man Member Posts: 3,276
    edited November -1
    quote:Originally posted by Tailgunner1954
    Measure your "short" brass after resizing, bet you'll gain back your length.
    The case gets fatter when fired, but the amount of brass remains the same, guess where the brass came from.


    [;)]
  • Laredo LeftyLaredo Lefty Member Posts: 13,437 ✭✭✭
    edited November -1
    quote:Originally posted by NeoBlackdog
    Thanks TG & 243. I suppose that makes sense. The load I'm using is not particularly stout, but it is pretty accurate. 24.5 grains of H335 under a Berry's 55 grain plated bullet and CCI small rifle primers that gives me .75" groups a 100 yards from a 16" pencil barrel.


    That recipe is reasonable. I use lots of H335 and have loaded them up to 26 grains. 3/4" MOA from a 16" thin barrel is very good. Looks like you have a load your gun likes. As mentioned, brass gets longer from sizing not shooting, That's why Dillon makes a trimmer to use when sizing the brass.
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