Quantcast
  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Using an auto pistol barrel find a MAX O.A.L with your bullet

Discussion in 'Handloading and Reloading' started by Walkalong, Feb 20, 2010.

Thread Status:
Not open for further replies.
  1. Walkalong

    Walkalong Moderator

    Joined:
    Nov 20, 2006
    Messages:
    47,602
    Location:
    Alabama
    This topic comes up a lot, or should I say this question.
    A short throat is sometimes the culprit. Too long an O.A.L. is sometimes the problem, even with barrels with average throats.

    This pic is often used to help explain correct headspacing and how O.A.L. can affect chambering and headspace.

    [​IMG]
     

    Attached Files:

    Last edited: Nov 14, 2016
    Phlier likes this.
  2. Walkalong

    Walkalong Moderator

    Joined:
    Nov 20, 2006
    Messages:
    47,602
    Location:
    Alabama
    I decided to do a little testing (with pics of course) with a couple of .45 ACP barrels and Precision 200 Gr SWC's.

    The first barrel is a Fire Dragon barrel. A .894 long case dropped around .013 below flush. I started way long on the O.A.L. and went from there. The second is a Wilson. The .894 case dropped .008 below flush in it.
     
    Last edited: Feb 20, 2010
  3. Walkalong

    Walkalong Moderator

    Joined:
    Nov 20, 2006
    Messages:
    47,602
    Location:
    Alabama
    .45 ACP Fire .45 ACP Fire Dragon barrel.
    Seating Depth, O.A.L. & Chambering - Fire Dragon Barrel Pic 1.JPG
    Seating Depth, O.A.L. & Chambering - Fire Dragon Barrel Pic 2.JPG
    Seating Depth, O.A.L. & Chambering - Fire Dragon Barrel Pic 3.JPG
    Seating Depth, O.A.L. & Chambering - Fire Dragon Barrel Pic 4.JPG
    So far so good. This O.A.L. would probably work.
     
    Last edited: Nov 14, 2016
  4. Walkalong

    Walkalong Moderator

    Joined:
    Nov 20, 2006
    Messages:
    47,602
    Location:
    Alabama
    Notice how another .014 shorter O.A.L. did not go any further below flush. Still .007

    [​IMG]

    Notice how just a light taper crimp on the 1.239 O.A.L. round dropped the round another .004 deeper.

    [​IMG]

    [​IMG]


    Note: - Fire Dragon Barrel

    A case .894 long and sized around .466 to .468 at the case mouth was .014 below flush.

    A case loaded with a bullet that was now .470- at the case mouth would only go .011 below flush.

    .
     
    Last edited: Nov 14, 2016
  5. Walkalong

    Walkalong Moderator

    Joined:
    Nov 20, 2006
    Messages:
    47,602
    Location:
    Alabama
    .45 ACP Wilson barrel

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    This O.A.L. would probably work. It may need to be a hair shorter. Should give good accuracy
    .
     
    Last edited: Nov 14, 2016
  6. Walkalong

    Walkalong Moderator

    Joined:
    Nov 20, 2006
    Messages:
    47,602
    Location:
    Alabama
    [​IMG]

    Notice how this time a crimp was no help in getting the round deeper in the chamber

    [​IMG]

    [​IMG]

    Note: - Wilson Barrel

    A case .894 long and sized around .466 to .468 at the case mouth was .008 below flush.

    A case loaded with a bullet that was now .470- at the case mouth would only go .003 below flush.

    .
     
    Last edited: Nov 14, 2016
  7. Walkalong

    Walkalong Moderator

    Joined:
    Nov 20, 2006
    Messages:
    47,602
    Location:
    Alabama
    Now that we have our MAX O.A.L. with a bullet and a barrel, we can tweak it for feeding.

    If you have several .45 (or whatever) barrels and want an O.A.L. that feeds and chambers in all of them, you will need to find the shortest max, and see if it works in all your barrels. Chances are it will.
     
  8. R.W.Dale

    R.W.Dale Member

    Joined:
    Oct 14, 2005
    Messages:
    11,379
    Location:
    Northwest Arkansas
    Great sticky worthy write up!

    But may I suggest you edit your title to reflect this is for a Pistol

    While the principal is the same for a rifle the method of determining is completely different
     
  9. mdripley

    mdripley Member

    Joined:
    Jan 26, 2007
    Messages:
    20
    Thanks very much for the illustrated information, this is just what I needed.
     
  10. Walkalong

    Walkalong Moderator

    Joined:
    Nov 20, 2006
    Messages:
    47,602
    Location:
    Alabama
    You are right. I will do just that.

    That better? Any more suggestions?
     
  11. jcwit

    jcwit Member

    Joined:
    Oct 19, 2007
    Messages:
    8,011
    Location:
    Great state of Indiana
    This should be a sticky. Come on mods
     
  12. 1SOW

    1SOW Member

    Joined:
    Oct 28, 2007
    Messages:
    4,106
    Location:
    South Texas
    Great camera work and labelling.

    Thank you....again.
     
  13. 243winxb

    243winxb Member

    Joined:
    Jul 7, 2004
    Messages:
    9,129
    Location:
    Hopewell Big Woods
    Good job Walkalong, adding the light taper crimp on the fire dragon barrel dropped the below flush* down another .004" Right above the photo is posted
    But the photo below has a type O i think?? on the measurement. (1.239" - 1.329") I would like to know the measurement from the head to the shoulder of the bullet on the fire dragon with a oal of 1.239" Thank you. Mine measures .947" [​IMG][/URL][/IMG]
     
    Last edited: Feb 20, 2010
  14. shootinxd

    shootinxd Member

    Joined:
    Dec 31, 2007
    Messages:
    208
    Hi Walkalong,
    What effect will this have on pressures with all things being the same with very light crimp.Should starting load be used or below that?The reason I ask is I had my Fire Dragon barrel break at the locking lug today after only 100rnds using the method in this thread.By the way it is a 40 cal XD.175grn,5.5 grn of AA#5.but seated below lee specs.
     
  15. Walkalong

    Walkalong Moderator

    Joined:
    Nov 20, 2006
    Messages:
    47,602
    Location:
    Alabama
    Both rounds are 1.239 O.A.L.. The only difference was the crimp narrowing the case mouth and allowing it to drop a bit deeper. I don't know the measurement to the shoulder. I have already seated it deeper so I cannot check it without doing up another round. It isn't important to this exercise.

    If I wanted to seat the bullet to just touch the lands, I would put the final crimp on before I got to flush, and then slowly work my O.A.L. down until I was happy with the relationship of the bullet and case to the lands/chamber. I would not try to measure the distance to the shoulder as a reference for other bullets. I would repeat the procedure with other bullets. That is how I would do it anyway.

    I don't load to touch the lands in any of my auto calibers by the way. They already out shoot me anyway. I load for 100% feeding, and take what I get. I'm not shootin' Bullseye, just playing around.
     
    Last edited: Feb 20, 2010
  16. Walkalong

    Walkalong Moderator

    Joined:
    Nov 20, 2006
    Messages:
    47,602
    Location:
    Alabama
    Obviously the pressure goes up a little as the O.A.L. gets shorter. How much is a job for a lab. When you get the O.A.L. you want to use, then yes, begin with a start load and work up.

    Too bad about that barrel, but I bet it was not pressure but a mechanical problem, assuming the loaded rounds headspaced OK, as in not too long, and were not really jamming into the lands.

    With only 5.5 Grs of AA #5, a 175 .40 Gr S&W bullet would have to be seated excessively deep to be over pressure IMHO.
     
  17. Tilos

    Tilos Member

    Joined:
    Jan 13, 2010
    Messages:
    706
    Walkalong, I always like your Pics

    Not to steal your thread, I want to offer another method I have used.

    An easy method to determine OAL can be done using a Digital or Dial Caliper and a new pencil cut about a 1/2 inch longer than the barrel.

    With the barrel removed, put just a bullet into the chamber until it stops and hold it there.
    Now put the cut pencil into the muzzle until it touches the bullet nose and measure the amount of pencil sticking out of the barrel.
    Use the step feature on the BACK of the caliper and note the measurement.

    Remove the bullet and re-assemble the barrel/gun.
    Now put that same pencil into the muzzle until it touches the breech face and again measure the amount of pencil sticking out of the barrel.

    The difference between the two measurements is the MAXIMUM overall length that will CHAMBER in THIS barrel/gun/bullet combination.(Fixed it, hows that:confused:)

    Walkalong, feel free to reduce all these words to 2 pictures!

    Note: The cut pencil must be square cut on both ends, not sharpened.:)
    This works for rifle too...with a really long pencil though.:D
    For my critics: If using a DIGITAL caliper, zero it on the 1st measurement and it will read the OAL on the 2nd measurement, no math required...or a micrometer:what:
     
    Last edited: Feb 22, 2010
  18. 1SOW

    1SOW Member

    Joined:
    Oct 28, 2007
    Messages:
    4,106
    Location:
    South Texas
    Actually, as Walkalong brought up, this isn't the MAX "USABLE" oal. This measurement would be touching the leade/lands and would give high pressure spikes.

    As taught to me by an old knowledgeable reloader (yea, I am thinking of you) you need to subtract your "max 'press' seating deviation" and a reasonable jump to the lands.
     
  19. bds
    • Contributing Member

    bds Member

    Joined:
    Jan 10, 2010
    Messages:
    14,346
    Location:
    Northwest Coast
    A picture is worth a thousand words ... and you posted a lot of pictures! :D

    Keep up the great work!
     
  20. Oyeboten

    Oyeboten Member

    Joined:
    Mar 23, 2008
    Messages:
    3,696
    Hi Walkalong,


    What a nice, well done presentation.

    Very good info, anyone Loading for Automatic Pistols will do well to look over.
     
  21. The Bushmaster

    The Bushmaster Member

    Joined:
    Jan 29, 2005
    Messages:
    7,857
    Location:
    Ava, Missouri
    Walkalong...Can I have your autograph?? (Before you get too famous)
     
  22. crashclint

    crashclint Member

    Joined:
    Feb 15, 2010
    Messages:
    17
    Location:
    Wake Forest, NC
    Thanks Walkalong, I will have to give this a go. I appreciate you taking the time with the pics and sharing this information.
     
  23. joneb

    joneb Member

    Joined:
    Aug 18, 2005
    Messages:
    3,742
    Location:
    Oregon
    Nice job Walkalong, So what camera did you get :)
     
  24. Epicurean

    Epicurean Member

    Joined:
    Oct 26, 2009
    Messages:
    47
    Location:
    South Carolina
    Walkalong - this is manna from heaven for a newb like myself, but I'm still a little confused. I'm loading 9mm right now (115 grain Missouri Bullet LRN with 3.0 grains of Clays) and the Hodgdon site says OAL is 1.100 inches. I have four pistols in this caliber so. taking your advise, I'm loading to the shortest max. which turns out to be 1.069" for my SIG P6. My EDC is a SIG P239 and it worked out to be 1.095". My P226 can handle 1.108". What's really confusing is that my H&K P7 doesn't have a barrel hood and the 1.069" load protrudes way out the breech; but being a polygonal barrel I probably won't shoot lead in it. So, do I load to 1.069" which is way below Hodgdon COL for the other three guns?
     
  25. Walkalong

    Walkalong Moderator

    Joined:
    Nov 20, 2006
    Messages:
    47,602
    Location:
    Alabama
    I don't see how you can get into trouble with 3.0 Grs Clays, even at that shorter O.A.L. Maybe one of the folks with Quickload can run it for you - Hint Hint. Clays is very fast, and is not real forgiving once it gets up there a bit in pressure.

    While 700X is often by Clays in the burn rate charts, it is much more forgiving, and has worked well for me in 9MM, even with plated bullets as long as I don't push it real hard. W-231 would be another good one.

    I think you will be fine though.

    Hodgdon shows:

    115 GR. LRN / Hodgdon Clays / .356" / 1.100" / 3.0 / 954 / 25,300 CUP / 3.4 / 1039 / 31,000 CUP

    If you have a chrono, as long as you don't exceed 1039ish FPS, I would say your pressure is fine.

    Clays is definitely not a good choice for speed in 9MM, as I am sure you are aware. AC
     
Thread Status:
Not open for further replies.

Share This Page