Hornady L-N-L Cartridge OAL gauge.

Discussion in 'Ammunition & Reloading' started by cpttango30, Mar 14, 2011.

  1. cpttango30

    cpttango30 New Member

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    We are going to talk about the Hornady OAL Gauge. You use this to determine your MAX OAL for a specific cartridge and bullet combo. In this we are going to be getting the MAX OAL for my 308 win using 175gr SMK bullets.

    First you need a few tools.

    1. Curved or straight (I have straight) OAL gauge.

    2. The Modified case for your rifle.

    3. Cleaning rod (WITHOUT TIP).

    4. Comparator Body.

    5. Comparator Body Insert.

    6. Caliper.

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    1. Ok first start by screwing your modified case on to the gauge rod. If you wish you can use a fireformed case and get the drill and tap kit as well. This will only give you better results. I have the Hornady supplied case. Now you should have your rifle in a vice or a cleaning rack of some kind. Here I am using a Tipton Gun Vice.

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    2. Now you want to assemble your comparator body with the proper insert. Simple to do put insert into body and tighten Allen nut to lock it in place. Then we want to put that on the back jaw of our dial or digital caliper.

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    NOTE: That the caliber is ZEROED on the Comparator.

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    Cont....
     
    Last edited: Mar 14, 2011
  2. cpttango30

    cpttango30 New Member

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    3. Now we need to load the bullet into the case. The case is inside neck reamed to allow the bullet to slide into and out of the case easily.

    [​IMG]

    4. Now insert the case WITH BULLET into the chamber of the gun. Pressing firmly to seat the case in the chamber.

    [​IMG]


    5. Once it is seated loosen the set screw slightly and press on the back of the gray center rod to press the bullet into the lands and grooves. DON'T HE-MAN IT. Once seated tighten the set screw. Again DON'T HE-MAN IT the inner rod is only plastic. and you don't want a bunch of divots in the plastic.

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    Cont...
     

  3. lonyaeger

    lonyaeger Active Member

    Very nice job, I have a question for you when you're done.
     
  4. cpttango30

    cpttango30 New Member

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    6. Remove the gauge with the case. DON'T PANIC. The bullet is stuck in the lands and groves that is why you have the cleaning rod. GENTLY run your cleaning rod down your barrel from the muzzle end, until you feel it contact the bullet. Then GENTLY press the bullet out it shouldn't take much force (UNLESS YOU HE-MANED the bullet in to the throat).

    [​IMG]

    7. Now place the bullet back into the case and you are ready to measure.

    [​IMG]

    8. Measure the OAL with your caliper. Making sure to hold the bullet up or at an elevated angle so it doesn't fall out. I like to gently rock my caliper on the base of the case then lock it at the shortest measurement.

    [​IMG]

    Now you know your MAX OAL. You can now adjust your seating die to seat shallow then slowly down to your proper depth. Mine measured 2.177" I want .018" jump for my load so I will set my die to 2.159".

    This is the best tool for when you are reloading and want to vary your seating depth to see how it affects accuracy. It is a well built product and will last you a life time. This is just one more tool to make your reloading that much more a PITA.... Not really.
     
  5. cpttango30

    cpttango30 New Member

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  6. lonyaeger

    lonyaeger Active Member

    This answers questions I've had for a long time:

    1. I could never before figure out how to know when the bullet is at the lands, which I know allows for maximum accuracy. Now I know....and thanks!
    2. Once I've determined the OAL for each rifle, I want to make EVERY cartridge for that rifle that length, correct? Regardless of bullet, brass, powder, or whatever.

    Another job well done. Where did you get the tool?
     
  7. cpttango30

    cpttango30 New Member

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    1. Yes you can load to or beyond the max OAL with extreme caution. Never load a MAX load with the bullet touching or jammed into the lands and grooves. Most rifles prefer a little jump. I have found that most run from .020 to .040" of jump to achive max accuracy.

    2. Once you determine the max OAL for that bullet you are done for that bullet. Different bullets have different ogives. That will affect OAL measured on the ogive like this does.

    a 155gr SMK is shorter than the 175gr SMK so you can load it out further. You still have to adjust each bullet for maximum accuracy. But yes you can load them all to the same length if you want. Just remember you have enough bullet in the case.

    I have found that you don't want the base of the bullet any deeper than the bottom of the shoulder for the best accuracy. You also don't want to little in the case because then it is not supported properly.
     
  8. lonyaeger

    lonyaeger Active Member

    I see they have them at Midway and Cabela's.

    One more question: what's the difference between the curved and the straight?
     
  9. Txhillbilly

    Txhillbilly Well-Known Member

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    Lon,the straight one works on any rifle that you can take the bolt out of,the curved one is for lever actions,or guns like a M1A,Garand,Mini 14,etc.that has no way for a straight tool to go into the chamber.

    Tango,Great write up.I'm sure some of the guy's new to reloading will like it.
     
    Last edited: Mar 14, 2011
  10. lonyaeger

    lonyaeger Active Member

    That's what I thought, thanks THB.
     
  11. Txhillbilly

    Txhillbilly Well-Known Member

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    Tango makes some good points here.
    You also have to take into consideration the maximum length the cartridge can be,in order to keep each rifle functioning as a multi shot weapon.

    In most cases if you stretch out the OAL,the cartridge will be too long for the guns magazine whether it's blind or box style and then the weapon becomes a single shot rifle.

    This is fine for target shooting,but if you want to hunt with the particular bullet,you might want to measure your maximum magazine length and start there.
     
  12. lonyaeger

    lonyaeger Active Member

    The modified cases are all on backorder at both Midway and Cabela's! :(
     
  13. Eric0424

    Eric0424 New Member

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    You can buy a tap and the appropriate drill bit then make all the cases you need. I'm betting tango knows the right tap/drill bit to use. :)
     
  14. cpttango30

    cpttango30 New Member

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    You can order direct from Hornady.

    Hornady Manufacturing Company :: Reloading :: Metallic Reloading :: Tools & Gauges :: Lock-N-Load Gauges-Formerly Stoney Point :: OAL Gauges & Modified Cases :: Modified Cases

    Sinclair has the cases as well.

    Sinclair Search : Reloading Equipment : Measuring Tools : Hornady Modified Cases -

    There used to be a kit that had the right drill bit and tap to modify your own case.

    I do believe you can buy a 5/6"x36tpi tap and size K drill bit and use that. I am not sure on this.
     
  15. lonyaeger

    lonyaeger Active Member

    After I posted, I found .308 and .223 at Sinclair's; I backordered for .22/250 and .243. Thanks.
     
  16. 338winmag

    338winmag New Member

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    "I do believe you can buy a 5/6"x36tpi tap and size K drill bit and use that."

    It is a 5/16 x 36. The problem is it is not a standard tap size and so far I have found to get it costs a lot more than what you want to spend.

    I have been using this tool with my 338 winmag and it is great... but this is the second time I have run into Hornady not having stocked product. I need a 270 Win. The backorder is weeks if not months from now (I called). Also getting a custom one made is 3-6 weeks out as well. I dropped another company because of this in the past.
     
  17. Eric0424

    Eric0424 New Member

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    Yeah, they can get expensive, I've considered taking out a loan for $7 to get the one below. Might have to sell a kidney to cover shipping though. :D I also like to buy the matching die for these special pitch and/or left hand taps, if you know where to look (Victor Machine for example) both can be bought for less than $10 each. Although I think Victor has a $25 minimum order.

    Inch/Standard Special Thread Taps

    The corresponding "K" drill for above tap, you can use a 9/32 drill as well since it's only .0002" bigger and may even be a drill bit some of us have laying around anyway.

    HSS Jobber Drill
     
    Last edited: Mar 22, 2011
  18. 338winmag

    338winmag New Member

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    Excellent info. Yeah I didn't look hard enough. ;) I saw one for $41.00 + shipping and gave up the search afer a few similar prices. Thanks man. I am going to purchase and make my own.

    Thanks for the post. Much appreciated.
     
  19. Eric0424

    Eric0424 New Member

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    I'm a little stubborn when it comes to things like that. I saw the $40-60 price tag on some and figured I could find them for less if I searched long enough. I've bought from Victor Machine several times over the years, as well as Enco, Little Machine Shop and lot of others, and I'm about to order a 7/16-20 left hand tap and die from Easton Supply soon for a project that's coming up.

    You would also be surprised what turns up on e-Bay some times, I picked up a few Bodine gear motors for $50-70 a piece about 2 years ago for my Taig Micro Lathe I was setting up. All of them worked perfectly and one of them was brand new.
     
  20. david12601

    david12601 New Member

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    bought tap

    Huron Industrial supply I bought the tap for $ 7.32 was $2.57 to mail to new york state .........made up 6 calibers on monday