Seating the bullet just off the lands.

Discussion in 'The Ammo & Reloading Forum' started by .308 shooter, Sep 3, 2008.

  1. .308 shooter

    .308 shooter New Member

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    Any suggestions on how to properly do this? I've successfully shot my first and second round of reloads and want to improve them. I know seating just off the lands should help.

    I've read LD Bennets method Seat a bullet very long in a test case with no powder or primer. It should be such that the bolt will not close on the case. Use a finger to gently (!!) push the case in to the chamber, then slide a slender rod (an aluminum cleaning rod works fine if the end is blunt) into the barrel muzzle until it just touches the bullet’s pointed end. Playing the case against the rod lightly seat the bullet into the lands of the barrel. Mark the rod where it exits the crown of the barrel. Remove the case and close the bolt. Push the rod into the barrel until it touches the bolt face and make another mark on the rod. The difference between the two marks is the maximum length the cartridge can be without the bolt having to force the bullet into the lands. Repeat this measurement until you are sure it is consistent and correct. Subtract about 0.002 inches from that dimension and that is the cartridge overall length the ammo should be made to, to get the bullet just off the lands in the bore of the barrel. Seat a bullet to that dimension in a dummy case (no powder or primer) and verify that the bolt closes normally without resistance.).

    I'm not sure I completely understand this one. Are there other methods or is this the best?
  2. LDBennett

    LDBennett Well-Known Member

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    What part do you not understand?

    The concept is you use the case as a holder for the bullet. Then you push the bullet into the barrel so that it just engages the rifling. You stick a rod down the barrel to just touch the bullet nose and mark the rod at the muzzle. You remove the bullet and close the bolt. The rod is now pushed farther into the barrel to touch the bolt face and another mark is made on the rod. You then remove the rod and measure between the marks and that is the length of a cartridge that would have a bullet seated in it so that the bullet touched the rifling lands. But that is risky to load that way as the bullet needs to have few thousandths of free run before hitting the lands or the pressures get astronimcal. So you subtact 0.001 to 0.002 inches from that measured OAL to get to a OAL that is just off the lands.

    I didn't invent this method. It actually appears in a reloading manual so it should not be controversial. I have tried the smoking of the bullet and various seating depths to find that same OAL and the results were not consistent. I even bought the special tool and it too did not give what I considered consitent results. The above method gives the most consistent results for me.

    Even if a person does not subscribe to bullets just off the lands you need to know what the max OAL that it takes for your particular rifle to be able to accurate set the bullet some other distance off the lands. The numbers given in the reloading manual are safe numbers and no way represent your particular rifle.

    LDBennett
  3. Bindernut

    Bindernut Well-Known Member

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    That's the method that I use too to determine the "land seating" over all length.
    I use a hardwood dowel instead of a cleaning rod, but either will work just fine.

    First measurement (after seating a dummy cartridge with bullet as LD described) = the distance from the tip of the bullet to the muzzle,
    Second measurement (with no cartridge in the chamber at all) = the distance from the breech face to the muzzle. This will be where the rear of the cartridge is on a chambered round.

    Maximum cartridge overall length = the second measurement - the first measurement.

    This is the length you need to make your cartridges to seat the bullets on the lands. For safety, subtract 0.002" from that measurement to keep the bullet 0.002" off of the lands. Let's call this the Maximum SAFE Cartridge Length.

    Also remember that this Maximum SAFE Cartridge Length will be different for each brand/weight/style bullet you use. So if you change any of those factors, you'll have to repeat the above measurements again for the new bullet.
    For each rifle and each bullet, I pencil those specs into my reloading journal so I've got the numbers handy for future reference.


    In case you haven't started one, get yourself a notebook and start a reloading journal to keep track of what loads you've tried, how they worked for ya (high-pressure signs, accuracy, etc). I also track the weather conditions on the day I did the shooting and how I was shooting that day (was I in a hurry, just killing time, did my shoulder or hands hurt from blasting several hundred rounds downrange already, stuff like that).
    This can help you remember what is working and what isn't. Can also help pinpoint things to avoid or try again the next time you hit the range too.

    Hope this helps and doesn't confuse ya even further.
  4. .308 shooter

    .308 shooter New Member

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    Okay gentlemen..... here's what I did on my lunch break.
    Seated a bullet in a case... very long
    Placed it in the chamber until the bullet stopped.
    inserted a wood dowel until it hit the bullet and marked it.
    Removed the cartridge - closed the bolt - inserte dowel and marked it.
    measured the distance.

    I came up with 2.789. Question... is that the distance from the tip of the bullet or the ogive of the bullet? My guess is the ogive.

    2nd question..... when using the comparator, I get different readings... depending on how "level" the ogive is on the bullet. Should I measure from the flat top of the comparator and the bottom of the bullet, making sure the are "leveled" on my caliper bases? I don't know if I explained that correctly.... I'm not very technical. I can understand technical, just not speak it.


    Got to go back to work now... just had to take time to try this. Let me know....

    Thanks and sorry so "vague"on my explanation.

    Jamey
  5. Bindernut

    Bindernut Well-Known Member

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    Your measurement with the dowel will be the overall measurement from the base to the tip of the bullet.

    I've never used a comparator type gauge for measuring cartridge length. Extra cost and the dowel/rod method has always worked for me. Maybe someone here that uses that type of setup can help you out with it.
  6. .308 shooter

    .308 shooter New Member

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    Here's my problem. I measured the distance marked on the dowel and it came up to 2.789. If that's the distance from the base of bullet to the tip of the bullet, then it's smaller than the COL listed in the handbook. It's my understanding that measurement is the measurement for most guns.

    I've just successfully loaded and shot my first batch and the loads were great. My bolt closed easily and my COL measured 2.81 which is larger than the dimension using the dowel rod method.

    I'm confused... shouldn't the COL be larger than my last load if I'm seating to the lands (or just before)?

    Thanks,

    Jamey
    Last edited: Sep 3, 2008
  7. Popgunner

    Popgunner New Member

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    You'd be ending up with the measurement from the base of the case or the bolt face to the tip of the bullet .

    This is assumingtwo things though. One is that the crown of the muzzle isn't tripping you up with your marking-you've got to be exact there, & two that you actually have the bullet that's seated out long actually touching the lands of the riflling. You could do like I do & cover the ogive clear to the tip with dark marker pen & re-try. You should end up with noticeable little rifling marks on your bullet.

    I would give it a little more than .002" of jump. I use .030" from the lands when I seat out long. Remember that you want to seat out long at the starting load because seating long in a rifle round raises pressure. Then work up from there to be safe.
  8. LDBennett

    LDBennett Well-Known Member

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    308 shooter:

    I think your measurement to the bolt is corrupted by the dowel touching the extractor or ejector. Try again. This measurement should be much longer than that listed in the manual, as you guessed. Maybe you need a skinnier dowel. A 22 cleaning rod with a blunted end usually misses those two items.

    Yes, you are measuring to the bullet end, not the Ogive, but if you want to be more exact then follow the extra steps here:

    After you have the two meausrement and have subtracted the 0.002 inches set up the press seating die to make a dummy round that exact length using the test bullet (Only the test bullet...any other will screw up the precision measurement). Now you can use the comparator to get the dimension you make all the ammo to using the comparator.

    Popgunner said:

    "I would give it a little more than .002" of jump. I use .030" from the lands when I seat out long. Remember that you want to seat out long at the starting load because seating long in a rifle round raises pressure. Then work up from there to be safe."


    While I agree with the above I think we are now at the second stage of reloading where we have already tried the manual OAL and are trying the "almost touching the lands" approach. As long as we again use the starting load and work up, we can use the 0.002 inches off the lands, in my opinion. I have found over the years in my reloading (and your experiences may vary) that the best accuracy is with the bullet almost touching the lands. I start there but with the starting load and work up. I have never seen a problem with excessive pressures if I start with the starting load and the bullet is really 0.002 inches off the lands. This is a tricky measusement and can easily be done wrong (like touch the extractor or ejector with the rod or not get the bullet to be just touching the lands). I repeat it several times to assure I got it right then make up a dummy and check it as popgunner said but for not touching the lands after I subtract the 0.002 inches off the measurement. As popgunner is implying SAFETY FIRST.

    As an aside newbies, I think, should start with the manual OAL and not try this approach until they understand exactly what they are doing.

    LDBennett
  9. steve4102

    steve4102 Former Guest

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  10. knothead

    knothead New Member

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    .308 shooter. I am not a expert but heres my 2 cents worth,,, Ive tried the dowel,cleaning rod method and I think that measuring accurately from the marks scribed on the rod is very difficult, at least for these eyes. especially down to .002. Ive also used the hornady tool , it works pretty good but I usually take 4 or 5 measurements to double check myself. The other method I use is to run a fired case into sizing die only far enough to size about .005 to .01 of case mouth, just enough to lightly grip bullet, push bullet in case with your fingers just a little then drop in chamber and close bolt. open bolt and remove dummy cartridge, then measure lenght to ogive. do several times to confirm measurement. also check this measurement against those from the other methods. look into getting a copy of precision shooting reloading guide. midway usually has it. it has alot of good info. some of the info is for benchrest or other competition but most is useable to the rest of us. hope this helps!!!
  11. Popgunner

    Popgunner New Member

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    Welcome Knothead

    I use the same method as you. Marking a rod at the crowned muzzle & expecting to get a measurement down to an accurate .002" is impossible in my humble opinion.

    I do as you do-partially re-size a case & start a bullet that I have covered with dark marking pen into the case. It's no trick to chamber the round in a bolt gun & then extract it. If the bullet does stay in the lands it's no big deal. That's when the rod comes out & taps the bullet out. The bullet has marks showing where it was in the case as shown by the marker. More often though the dummy round comes out with marks showing the leads & is ready to measure for OAL.
  12. .308 shooter

    .308 shooter New Member

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    Thanks all. I triec the rod and dowell method and I was coming up with a measurement smaller than what I was already loading.

    I just got finished seating a bullet as to what I think is correct. I seated it, and checked to see if the bolt would close easily. Then repeated until the bolt closed with out resistance. I did this three times. Two were newly cleaned and sized cases, one was an older case I had been working with. The two newer cases were semi-consistent. Base to bullet was 2.850 and 2.855. Using the comarator nut, the measurement was 3.214 and 3.215 from base of bullet to top of comparator.

    Am I correct in assuming since the bolt closes without resistance that these are safe to test using live ammo? Starting at the minimum load of course.
  13. artabr

    artabr New Member

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    + 1 on the Knothead & Popgunner method. I start a bullet in a case with only .001 -.002" of neck tension, chamber it, measure the bullet at the ogive and set it back what ever distance you want. The reason I measure at the ogive is that bullets lenghts can very.

    This is a link to the tool that I use.

    http://www.sinclairintl.com/cgi-bin/category.cgi?category=RESDTCO&item=09-600&type=store

    Also, the book that Knothead mentions, I also highly recommend. It answers a lot of the questions we all have when we start to demand better preformance from our rifles and ourselves. :)
    The book is the 5th to last in the link below.

    http://www.precisionshooting.com/books.html


    Art
    Last edited: Sep 9, 2008
  14. RodneyJ

    RodneyJ New Member

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    I also use the methed that Knothead and popgunner use. It is the methed that is described in the Lee loading manual. I have used this methed for a bolt action and also a single shot brake open action with good results.
  15. gs1sniper

    gs1sniper New Member

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    308 shooter,
    I just did the same exercise but in a different manner. Take 3 empty cases and insert a bullet by hand long into the case. Gently put the case into the chamber and then close the bolt which pushes the bullet into the lands. Open the bolt and gently take the case out (without the extractor throwing it out) and measure your overall length. Ammosmith? on youtube gives a very good video of this procedure.
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