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Thread: .243 col

  1. #1

    .243 col

    Hi Guys I could do with a bit of advice please, Im fairly new to reloading Ive bought a couple books and been ploughing my way through them, but this is my question. Im reloading for my browning a bolt in .243 using Hornady 87grain V-max bullets the minimum col in my book(modern reloading second edition) is not listed. So I checked the maximum length by just seating a bullet in a already fired case and chambered the round, I got 2.726inches from the base of the cartridge to the plastic tip of the bullet. I then varied the charge weights of powder and seated all the bullets .020thou of the ring lands with my powder hogdons H4895 the best group I got was 1inch at 100 yards with a charge weight of 37grains, How deep can you go with bullet seating depth and will this have a massive effect on the accuracy and what increments would you adjust in eg .005thou increments etc

    Cheers
    John

  2. #2
    if you have a starting point and are getting reasonable groups,I would adjust the depth 10 thou at a time,you then should see a pattern emerge hopefully tighter.
    the way I do it which also saves on wasted rounds is to take your batch of bullets to the range along with your seating die and measuring equpiment.
    you will need a press also I find the LEE hand press to be perfect for this job.
    press 2 bullets in 10 thou and fire them,if they do not show any promise dont fire a 3rd
    pree another 2 bullets in another 10 thou and fire them,again if they dont show promise dont fire a 3rd
    keep doing this untill you you the 2 shot toucj or go through the same hole,then adjust a 3rd and fourth bullet and fire into the group.
    I have found I can usually get a rifle shooting within 12 shots or less using this method,providing your rifle likes the bullets you are using.
    please note this is my method of finding accurate seating depths Iam sure there will be others with different advice,also make sure you test from a solid stable platform with supporting bags or bipod (and not of sticks)
    good luck let us know how you get one,feel free to PM me if you need any further help

  3. #3
    1. You need a bullet comparator to measure the bullet ogive rather than the overall length to the tip of the plastic tip. They are less than 20 from Hannams or Reloading solutions, or MidwayUK as they are in Worcestershire somewhere.
    2. You need to measure the OAL of the chamber. You can buy the Hornady lock n load thing but it does not measure to the bolt face. I use a partially neck sized case so the bullet is a friction or sliding fit. Load the case and a bullet in the chamber and lock the bolt down then remove and carefully measure the OAL of the case and bullet for an average reading. Do this 5 times and take an average.
    3. Load bullets off the lands at increments of 0.030", 0.060", 0.090" and 0.120" in batches of 5 and shoot to see which ones are the most accurate. Then interpolate for finer results.
    In my 243 I seat the 87gr Vmax at 0.120" off the lands, but each rifle is different.

  4. #4
    Quote Originally Posted by see it shoot it View Post
    if you have a starting point and are getting reasonable groups,I would adjust the depth 10 thou at a time,you then should see a pattern emerge hopefully tighter.
    the way I do it which also saves on wasted rounds is to take your batch of bullets to the range along with your seating die and measuring equpiment.
    you will need a press also I find the LEE hand press to be perfect for this job.
    press 2 bullets in 10 thou and fire them,if they do not show any promise dont fire a 3rd
    pree another 2 bullets in another 10 thou and fire them,again if they dont show promise dont fire a 3rd
    keep doing this untill you you the 2 shot toucj or go through the same hole,then adjust a 3rd and fourth bullet and fire into the group.
    I have found I can usually get a rifle shooting within 12 shots or less using this method,providing your rifle likes the bullets you are using.
    please note this is my method of finding accurate seating depths Iam sure there will be others with different advice,also make sure you test from a solid stable platform with supporting bags or bipod (and not of sticks)
    good luck let us know how you get one,feel free to PM me if you need any further help

    this is a good process, but of course, assumes that the powder load is also good from the beginning. The way I've done it in the past is to start with 96% of max load, then do a 0.5grain load below that an another one 0.5 grain below that one, use the best group and then go through the seating depth process starting with a .243 from 2.70 COAL...mind you, the best loads I've found have interestingly enough been 'at' 2.7" COAL and 96% of max load,,which is pretty handy but made me waste a lot of ammo! LOL

  5. #5
    Good reloaders/shooters on this site like.
    Muir, Brithuntter,joe Bloggs, Brewser 500. Will mostly tell you to seat a caliber depth or to the shoulder of the case. If you did this you would be way off the lands. In fact the bullets I shoot from my .243 are home swaged 68gr hollow points. They would never get any where nere the lands.

    I find the good peoples above listed, advise to very accurate.

    That is what I was told to do when I started reloading so that what I do.

    So just to give another perspective on this.

    A inch group at a hundred yards is pretty good. If you don't want the hassle of measuring the COL. Then try a lee factory crimp die.

    Why do I say this?
    Accuracy comes from constancy.
    A rifle has a pressure band it likes. Find that pressure band and your on a winner. A lee factory crimp die will help you consistently stay in that pressure band( quite usefull if your not going to weigh every load(very boring) )).

    In my mind a inch group is not a bad indicator of being in that pressure band.

    Try the crimp!

    BTW.
    when my rifles group at an inch, I leave the load alone. I find an inch group a plenty accurate test,for a round to use on all the deer I shoot. Plus we all strive to make a one shoot kill don't we?

    However there seams to be a trend to make deer/sporting rifles shoot like bench rest.
    Quite sad really!
    Last edited by Simjim33; 08-03-2013 at 16:00.

  6. #6
    Quote Originally Posted by see it shoot it View Post
    if you have a starting point and are getting reasonable groups,I would adjust the depth 10 thou at a time,you then should see a pattern emerge hopefully tighter.
    the way I do it which also saves on wasted rounds is to take your batch of bullets to the range along with your seating die and measuring equpiment.
    you will need a press also I find the LEE hand press to be perfect for this job.
    press 2 bullets in 10 thou and fire them,if they do not show any promise dont fire a 3rd
    pree another 2 bullets in another 10 thou and fire them,again if they dont show promise dont fire a 3rd
    keep doing this untill you you the 2 shot toucj or go through the same hole,then adjust a 3rd and fourth bullet and fire into the group.
    I have found I can usually get a rifle shooting within 12 shots or less using this method,providing your rifle likes the bullets you are using.
    please note this is my method of finding accurate seating depths Iam sure there will be others with different advice,also make sure you test from a solid stable platform with supporting bags or bipod (and not of sticks)
    good luck let us know how you get one,feel free to PM me if you need any further help
    BE AWARE !!!!

    If you seat your bullets further into the case the pressure will increase.
    Even as a reasonably experienced reloaded, who knows what excessive pressure signs look like, I tend to seat out incrementally not in.
    The method I use is to measure chamber length, then seat the bullet 0.1 of an inch( that's 100 thousandths of an inch) into the case (others use a calibers depth into the case). Once you've established your powder loading at this seating depth, then start to move your seating depth out in increments of .005" until you find an accuracy node. By doing it this way you will reduce chamber pressure not increase it.
    Dcg
    Last edited by DCG; 08-03-2013 at 17:48.

  7. #7
    Quote Originally Posted by DCG View Post
    If you seat your bullets further into the case the pressure will increase.
    Even as a reasonably experienced reloaded, who knows what excessive pressure signs look like, I tend to seat out incrementally not in.
    The method I use is to measure chamber length, then seat the bullet 0.1 of an inch( that's 100 thousandths of an inch) into the case (others use a calibers depth into the case). Once you've established your powder loading at this seating depth, then start to move your seating depth out in increments of .005" until you find an accuracy node. By doing it this way you will reduce chamber pressure not increase it.
    Dcg
    obviously depends on the powder charge to start with,by pressing the bullets in you save a lot of wasted ammo once the seating depth is found you can then play with powder if needed,Ive been using this method for years and has served me well plus no complaints form the people I have developed for,in fact i have 2 rifles in at the moment being worked i n the same way.
    but as I always say people do things differently.
    I wonder how many of these expert loaders on here actually use a chrono ???

  8. #8
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    i use 87 grain vmax in my 243 my are set a 2,690 OAL, with 35 grains of N150, i get nearly one hole groups , hope this helps ya

    ATB
    Dave

  9. #9
    Quote Originally Posted by see it shoot it View Post
    obviously depends on the powder charge to start with,by pressing the bullets in you save a lot of wasted ammo once the seating depth is found you can then play with powder if needed,Ive been using this method for years and has served me well plus no complaints form the people I have developed for,in fact i have 2 rifles in at the moment being worked i n the same way.
    but as I always say people do things differently.
    I wonder how many of these expert loaders on here actually use a chrono ???
    No criticism of your method and I'm always keen to save on time and consumables but this guys a newbie. I learned about over pressure the hard way a few years ago now, fortunately no harm done to either myself, anyone else, or my equipment, except having to clean bits of brass out of the bolt.
    I had use of a chronograph a few years ago and have recently acquired another, not an essential piece of kit, but very useful for load development.

  10. #10
    Quote Originally Posted by johndownes View Post
    Im reloading for my browning a bolt in .243 using Hornady 87grain V-max bullets the minimum col in my book(modern reloading second edition) is not listed.
    Hornady 6th edition says COL for the #22440 87 gr V-MAX is 2.640"

    Quote Originally Posted by johndownes View Post
    So I checked the maximum length by just seating a bullet in a already fired case and chambered the round, I got 2.726inches from the base of the cartridge to the plastic tip of the bullet.
    A word of caution. If you are going to use that technique, you need to do the following.

    1. Use a junior hacksaw to cut a slot in the neck of the resized cartridge, along it axis. Cleane the slot with a file. This provides sufficient grip on the bullet but allows you to push it into the case, or pull it out, for adjustment

    2. Use a CD marker to black the bullet. Don't use just any marker, use a CD marker because they lay down a thin layer of ink.

    3. Use a 4x magnifiying glass to examine the bullet for marks from the lands. When the bullet is just touching the lands, the marks can be subtle. You need to be certain where your lands are.

    Measuring the OAL of the loaded round isn't ideal either because bullet lengths vary. Ideally, you would use a bullet comparator which measures to a datum point on the ogive.

    -JMS

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