Hornady L-N-L OAL guage -- what am I screwing up?

Discussion in 'Reloading' started by mattj, Oct 25, 2008.

  1. mattj

    mattj Well-Known Member

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    Picked up the Hornady Lock-N-Load (formerly Stoney Point) OAL gauge in hopes of streamlining the process of finding my seating depths. I'm using the curved version on Zediker's recommendation.

    Plan was to use the gauge to find my touching-the-lands depth to more quickly "zero" my micrometer seating die. The experience with the tool so far has been a bit... baffling.

    I'm hoping that somebody can tell me how I'm being an idiot....

    Here's my procedure:

    I screw the dummy cartridge into the gauge, put one of my bullets in there seated extremely deeply to start, and push the piano wire plunger until it touches the base of the bullet. I insert the dummy cartridge all the way into the chamber, and maintain enough pressure to keep the case shoulder in contact with the chamber. I then push the piano wire plunger to increase the seating depth of the bullet in the dummy cartridge until I feel resistance, and then tighten the thumbscrew to lock the plunger at that depth. I remove the device from the chamber -- sometimes the bullet comes out, sometimes I have to gently tap the butt of the rifle on the ground to knock it free.

    After removing the gauge, I re-insert the bullet until its base is touching the plunger, and then use the Hornady LnL bullet comparator to measure the length of the dummy cartridge + bullet, indexing off the ogive.

    So, the seating depth of the bullet in the OAL gauge's dummy cartridge when I follow this procedure (measured in terms of bullet base to ogive) *should* correspond to the seating depth (again, measured in terms of bullet base to ogive) where a loaded cartridge would be just touching the lands... right?

    But here's the head scratcher:

    If I load a cartridge to that seating depth, the bolt will not close. I have to seat the bullet almost .2" deeper in order to get the bolt closed.

    The problem isn't head space or neck length, because I can chamber the brass before loading the bullet, and if I keep increasing the seating depth, I eventually get to where I can close the bolt...

    I've tried this multiple times -- using different individual bullets and brass and have obtained the same results.

    Everybody seems to think the OAL tool is be best thing since sliced bread, so I'm sure I'm doing something wrong -- but I'm stumped as to what my folly here could possibly be.

    Any ideas?

    Thanks,

    Matt
     
  2. gahlizard

    gahlizard Well-Known Member

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    are you using one of their generic dummy cartridges or did you send them one fired out of your rifle?
     

  3. mattj

    mattj Well-Known Member

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    Using the generic one -- though I'm also using fresh full-sized brass.

    You're right though -- it had not occurred to me that the depth the bullet ends up seated in the dummy bullet will be directly affected by the head space of the dummy cartridge.

    Sounds like I need to compare the headspace of my real brass and the dummy cartridge.

    Thanks for the insight.
     
  4. mattj

    mattj Well-Known Member

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    Hmm, the dummy cartridge measure the same as my sized brass on the Hornady headspace gauge -- though that indexes off of just the one point on the shoulder, I suppose it could still "bottom out" against the chamber at a different point than the brass if it is not shaped correctly.
     
  5. loaders_loft

    loaders_loft Well-Known Member

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    I use the straight version because I only use it for bolt action rifles.

    For the straight model, Hornady's website says, "For all bolt action and single-shot firearms, or any firearm with straight-line access to the chamber. This model is preferred, as it is most precise and user friendly."

    For the curved model, Hornady says, "For all autoloader, lever-action, or pump-action rifles. Also fi ts all bolt-action and single-shot firearms. Inserts into chamber through ejection port."

    If yours is a bolt action, maybe you should abandon the curved model and get the straight model?

    I take 3 measurements when using a new bullet. Sometimes I get an artificially high number, from applying too much pressure and jamming into the lands. It only takes a slight pressure to contact the lands. Maybe you're applying too much pressure and buckling the "paino wire plunger" within the tube, which would amount to excess length, thereby artificially extending your COL.

    Another thought - take your measurements with a comparator instead of measuring from the bullet tip.
     
  6. mattj

    mattj Well-Known Member

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    I went with the curved version because Zediker recommends it for all rifles in his book, said he found it to be the more consistant of the two versions, and works fine in bolt guns.

    I don't see any reason why the curved design should be the problem in a bolt gun.

    I am using the comparator to measure the seating depth, and get pretty close results over multiple attempts at using the tool.

    Good point on bending the piano wire -- I don't think I was pushing it very hard, but I will try again when I have a chance, concentrating on using the super light touch.

    Thanks for the reply.

    -Matt
     
  7. longrange.270

    longrange.270 Well-Known Member

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    What I did to find my OAL, was after I had fired some brass to my chamber, I neck sized them only. But just enough that you can put a bullet in the neck and it not fall out and is somewhat easy to push in, but still enough tenson. Then chamber the round in the gun and then when your taking it out, be careful not to push the bullet into the case anymore and then measure it and subtract .010, ten thousands, from that number and your good to go. But as long as you get the number after pulling it then you can go from there. I did it a couple of times just to be sure it was right. Sometimes the bullet will get stuck in the lands, but big deal. Here is the video to were I learned how to do this: YouTube - Making a Overall Length Guage or just search youtube for making a overall length guage. Hope that helps any.
     
  8. loaders_loft

    loaders_loft Well-Known Member

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    Okay, good luck and let us know what you find.
     
  9. cuutter

    cuutter Well-Known Member

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    The one thing wrong with the vid. is he tells you to load the bullet .100" shorter and I think he means .010". That would make more sence.
    Just my two cents.
    Good luck
    Wayne
     
  10. johnnyk

    johnnyk Well-Known Member

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    mattj,
    I have both the straight and curved tool. I have occasionally had difficulty with some of the dummy cases not fitting in the chamber exactly like they should. I lube 'em up and run them through the FL die. This may not be the best method, as afterwards you have to open the neck of the dummy round back up in order for the right caliber bullet to freely slip in/out of the dummy case.
    This usually is not a problem if you have other caliber dies. Simply take the expander ball from another die (one size up) and swap it to the die used on the dummy case giving you the problems. I had trouble with my son's .260 Rem Mtn Rifle and just recently with my .270 WSM Coyote. Both cases gave me erratic readings no matter how hard I tried to control the pressure I applied to pushing the bullet into the LaG's. They both work like champs now.
    About the curved/straight tool. I have always used the straight one for all my rifles except for the Browning BLR my dad left me. Of course I have to use the curved one for it and I didn't like it. Anyway, my straight tool recently broke right where the threads meet the tube, so I used my curved one on one of my bolt action rifles. I definately do not like the curved one with the "pianie" wire. Guess it'll take some getting used to but I plan on buying another straight tool asap (I wonder if Hornady will warrantee one of the older Stoney Point tools?). Doubt it. Happy reloading, JohnnyK.