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9mm keyhole

Discussion in 'Handloading and Reloading' started by cordercorral, Apr 2, 2013.

  1. cordercorral

    cordercorral Active Member

    9mm cast 147gr...tightgroup 3.4gr COLA 1.134, Tarus 1911 9mm.

    I get 4 out of 10 that are keyholed...what am I doing wrong?
  2. holdencm9

    holdencm9 Well-Known Member

    What twist barrel, and expected velocity for that load?
  3. cordercorral

    cordercorral Active Member

    Twist ?...Velocity 915
  4. Jesse Heywood

    Jesse Heywood Well-Known Member

    If you don't know the barrel twist, post the gun make & model.
  5. 7.62 Nato

    7.62 Nato Well-Known Member

    Taurus 1911 9mm
  6. david_r

    david_r Well-Known Member

    My crystal ball says it is a taurus 1911 in 9mm
    Last edited: Apr 3, 2013
  7. David E

    David E Well-Known Member

    Too tight a crimp, bullet undersized, bore oversized OR....

    Change the powder to something other than Titegroup.
  8. ArchAngelCD

    ArchAngelCD Well-Known Member

    Is that velocity a guess or did you measure it yourself? I'm looking at the Hodgdon site and they list a 147gr Hornady XTP bullet with a charge range of 3.2gr to 3.6gr Titegroup. Since you're loading a lead bullet you should not be using load data for jacketed bullets. My Lyman Cast Handbook lists a charge weight range with Titegroup and a 147gr Cast bullet as only 2.5gr to 2.8gr. Your charge of 3.4gr is way over according to Lyman. Where did you get that load data? It's possible you are generating too much velocity which is preventing the bullet from stabilizing.

    Lyman tested their data with a 4" barrel.
    2.5gr Titegroup, 870 fps, 26,800 CUP
    2.8gr Titegroup, 943 fps, 30,300 CUP

    I highly suggest you drop your charge weight by a lot considering you're about 22% over the max charge listed in the Lyman load data...
  9. noylj

    noylj Well-Known Member

    COLA? Coke or Pepsi? If you mean COL, it is not a cause of bullet tumbling--that I know of, any way.
    Undersized bullet? What is barrel's actual groove diameter? Lead bullets should be 0.357" (works well in most all 9x19s) or at least 0.001" larger than groove diameter. I find .38 lead bullets work better than most 0.356" lead bullets.
    When you slug the bore, are there any extremely tight or loose areas?
    Heavy leading?
    Is there a nick or burr on muzzle?
    Throat or rifling problem?
    TiteGroup simply does not play nice with lead bullets in some guns--it burns very hot and just seems to love gas-cutting.
    Does it happen with other lead bullets?
  10. Blue68f100

    Blue68f100 Well-Known Member

    TG burns way too hot for lead/cast bullets. Change to something else like WSF.
  11. bds

    bds Well-Known Member

    I think bullets keyhole if they were not rotated enough in the barrel to stabilize in flight, due to undersized bullet/oversized barrel or bullet pushed by high pressure gas unequally exiting the muzzle due to uneven crown, etc. For short pistol distance keyholing like 7-15 yards, I think it's lack of bullet rotation caused by several factors.

    I am with ArchAngelCD that the 3.4 gr Titegroup charge may be driving the bullet too fast. Hodgdon lists 3.6 gr as max charge for 147 gr XTP jackted HP bullet at 1.100" OAL and Lyman #49 lists 2.8 gr as max charge for 147 gr lead bullet at 1.058" OAL. I am not sure what the groove diameter of the Taurus 1911 9mm barrel is but my guess is the overdriven bullet is not rotating sufficiently as it exit the muzzle to stabilize in flight.

    I would try 2.6, 2.7, 2.8 gr and see if these charges will cycle the slide and eliminate the keyholing problem. Since you are using longer 1.134" OAL than what Lyman listed, if the 2.8 gr charge won't cycle the slide reliably, I would try 2.9 and 3.0 gr. If lower powder charges work without producing keyholes, the bullets were driven too hard. If not, it's something else.

    BTW, are you getting any leading?
    Last edited: Apr 3, 2013
  12. JamieC

    JamieC Well-Known Member

    Assuming you could find some, have you tried any other ammo? As ArchAngelCD pointed out, (he is one who knows), you may deforming, burning the lead with not only too much powder, but one known to not play nice with lead.
  13. Kp321

    Kp321 Well-Known Member

    Had a similar situation years ago using faster powders with lead 147's in 9mm. Went to Blue Dot and got very accurate loads. Jacketed 147's did fine with Green Dot and Unique. Don't really have an explanation just a solution.
  14. GLOOB

    GLOOB Well-Known Member

    Pull a bullet and measure the base.

    I was having similar woes. When I measured the base of my bullets, some were getting swaged to < .353" by the case, during seating. And those were only 125 gr bullets. With a 147 gr bullet, you might be doing even worse.

    See, the 9mm case is short and tapered. The case starts to get thick quite soon in many headstamps. And when resized by a carbide die, the taper is removed. So the case gets "sucked in" and all that thicker brass gets squished in, leaving no room for the bullet.

    I was using Lee dies. I bought a 38S&W expander plug and swapped that into my 9mm expander die; and I seat the bullets so they don't go any deeper than where the expander plug ends. It solved my problem, 100%. Accuracy restored, fouling gone.
    Last edited: Apr 3, 2013
  15. greyling22

    greyling22 Well-Known Member

  16. chris in va

    chris in va Well-Known Member

    Yup, I got bad keyholing with 147gr 356's. i switched to a 358 125 and voila, perfect.
  17. bds

    bds Well-Known Member

    cordercorral, here's another thought.

    Missouri Bullet Company offers their 9mm 147 gr FP bullet in softer 15 BHN instead of 18 BHN. Perhaps there's a reason why they did that. ;)

    I am not sure if you slugged your barrel to check bullet-to-barrel fit for your Taurus 1911 but the softer 15 BHN bullet will deform/obturate easier to seal the bullet base to the barrel and rotate to prevent keyholing. If the barrel is really oversized, they will size the bullet at 1000+ quantities.

    ZCast also sells their 9mm 147 gr TC bullet in 14-16 BHN - http://zcastbulletz.com/order.html
    Last edited: Apr 4, 2013
  18. cordercorral

    cordercorral Active Member

    WOW! Thanks for the help. You all were correct in suggesting to much powder. I ended up @ 2.4gr tightgroup. Keyholeing stopped. Cycles great. Accuracy as good as 70 year old hand and eyes can shoot. LOL Thanks to all who helped. This is the best board for reloading!
  19. bds

    bds Well-Known Member

    Great! I love happy endings. :D
  20. ArchAngelCD

    ArchAngelCD Well-Known Member

    Outstanding, I'm glad everything worked out well for you...

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