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C.O.L where to begin?

Discussion in 'The Powder Keg' started by OldSchool, Mar 17, 2002.

  1. OldSchool

    OldSchool G&G Newbie

    As I've said before, I'm just getting my feet wet in handloading, in fact I put togather my very first handloads just today (I've had all my equiptment for over two months, but wanted to gather as much info as possible first). My question conserns cartridge overall length. I have the appropriate guage for determining maximum cartridge length and have experimented with a dummy round to find out the max that will cycle in my action. Should I start loading at the max length from the git-go or should I stay at SAMMI untill I find my best load and then experiment with seating depth?

  2. Jack O

    Jack O G&G Newbie

    It kinda depends on what your loading for. In semi auto pistol loads I go by published oal (over all length) for reliabilty. In abolt action it really shouldn't mater as longer as you don't get them to short and cause excessive pressure. Some people like to seat rifle bullets out to .020 from the lands of the rifling. That's done mostly for accuracy purposes. Starting at the maximum length in a max load is a good idea to keep pressure in check. Hope this helps if not be more specfic and will try again.

  3. sadiehn

    sadiehn G&G Newbie

    this is what I do may be right or wrong

    1 load using book COAL and basment load
    2 work my loads up in .5 grain increments of 10 rounds
    3 when I find my max load I back off .5 grains
    4 when i move my bullet out(longer) in .005 increments of 10 rounds
    5when shorting increments of .005 and 10 rounds

    this will give a good sample of accuacy and presure if you use 10 round it is a lot of shooting but what the heck
  4. Robert

    Robert Member

    Ok, bear with me..Some chambers differ. Use posted overall lenghts. If it seems like it is not accurate, this is what you do to tailor the chamber for your Specific firearm....
    Take a spent round that has been fired in your rifle/pistol.
    Bite it. Ha Ha. gently bite the neck so it is a little off round, you want the bullet that you are working up to stick in the neck a little..... put a round in an uncharged case and slowly...carefully close the action. Measure the Over all length. Back it off a c. hair. That is your overall length. It could vary from bullet to bullet depending on manufacturer and bullet weight. You dont want the bullet toching the lands, and you dont want it back so far that it is smashing into the lands. Where exactly that is.... seems to be a mystery to me. I have heard a lot of opinions. some people load OAL so it is 'just toching the lands/rifling. I like to stay back just a 'C' hair. (in laymans terms)
  5. Re: C.O.L.

    I'd do like the one guy suggested with coming up from the basement and working the load. Other than that, you can buy a Stoney Point O.A.L. gauge and caliber insert. Measure from the Stoney Point setting, and back off .020 to .040". The Stoney Point helps after you have fired a number of rounds and suspect barrel erosion.
  6. Shaun

    Shaun G&G Evangelist

    also if you are going for max length pay attention to the bullets OGive this is the shape of the bullet you might be running some type of bullet that is narrow with a nice point to it with one length that works perfectly. Then you might change bullet brands and the bullet could be fatter at a higher point which of course causes and earlier contact with the Lans. I have seen this happen and it sucks when you get a rifle round stuck and if your lucky the bolt can pull it out without taking the round apart. I had this happen to me last year and now I check for that as well
  7. sadiehn

    sadiehn G&G Newbie

    if you are going to load light bullets for the caliber IE.110 in 308 or 75 or 87 in 25 caliber you may be amazed that to get best accuracy back the bullet deeper into the case yes farther away from the rifling.but work either way in small increments
  8. jgang

    jgang G&G Newbie

    Just asked the same question today to a guy in a shop. Here is his answer. Lightly tap a bullet in to the chamber. Use your cleaning rod, inside of the barrel, to indicate the distance from the bullet to the crown. Mark this. Tap the bullet out, close the bolt and measure the distance from bolt face to crown and mark. Measure between marks and that is your max OAL. He subtracts .020 from this measurement to get his OAL. I haven't tried it but it sounds right.
  9. Robert

    Robert Member


    If you have a micrometer, it works better than a cleaning rod. You dont need to tap the bullet, just drop it into the chamber. It will seat in the lands. Most micrometers have a little tail peice on the bottom that is for inside measurements. It works just like reading measurements on the jaws. That will give you an accurate measurement from the base of the bullet to the breechface. But, then you have to set the bullet next to your case to measure from the base of the bullet to the base of the cartridge till it is the same first measurement. Now you can measure the OAL. It is a lot easier to just bite a cartridge neck, put a bullet in the neck so it is a little tight, and chmber it. The lans will push the bullet to its oal. Then, as Shaun said, back it of .020 and it will not be the same for instance, a round nose will have a different oal than a soft point or fmj.
  10. sadiehn

    sadiehn G&G Newbie

    that sounds a littel in acacurate for my taste get a COAL gage or do like the on man said bite the case and push the bullet in and measure use the exact same bullet create a dummie load (no primer powder) and set your die to its measurements
  11. OldSchool

    OldSchool G&G Newbie

    Thanks for all the advise. Getting the COL is'nt a problem, I've got the proper guage. I 'm going to start at SAMMI length untill I find the best load and then play with the length to see if I can tweak a little more accuracy out of them.

    Heres something intresting, try guaging your chamber length with each of the methods described above and see how much variation you get.

  12. sadiehn

    sadiehn G&G Newbie

    BEEN THEIR DONE THAT just so you know what i like is the COAL gage most consitant