Bullet Depth, "off the lands" vrs OAL?

Discussion in 'Reloading' started by justinp61, Aug 6, 2011.

  1. justinp61

    justinp61 Well-Known Member

    Messages:
    65
    Joined:
    Jul 31, 2011
    I've been setting up to load some shells for my new Savage FVSS 22-250. As I stated in one of my other questions, I'm new to rifle loading but not reloading in gereral.

    I've searched for loads for 22-250s similar (same rate of twist and barrel legnth) to mine. One thing I've noticed is some guys post the distance off the lands for their loads. How critical is this compared to the OAL?

    I measured the distance to the lands on my rifle. Right or wrong this is the way I did it. I took a once fired brass and had fed it into the resize die until it would hold a bullet very firm but I could still pull it out by hand. Then with the bullet pulled out long I would chamber the mt shell to seat the bullet, then measure it with my digital caliper. The anvil on my mic was to small to measure off the base so I used the caliper. I averaged 10 measurements to get the distance, 2.4630 was the average.

    I going to load Varget under Hornady 55gr V-MAX bullets. I measured the factory loaded Hornady 55gr V-Max they averaged 2.3430, .120 off the lands.

    Is there an acceptable range? How close is to close or to far?

    Thanks, please be patient as I will have other questions I'm sure.:)
     
  2. Greyfox

    Greyfox Well-Known Member

    Messages:
    3,689
    Joined:
    Jan 21, 2008
    I think you range is acceptable. I have factory rifles that that are over .150" off the lands and they are very accurate. It seems to depend on the particular bullet barrel combo. If the load is accurate to you standard, it's acceptable. Just make sue that if using a clip, that it will feed. For the real precision stuff I like using distance to the lands as opposed to OAL. It is typical for even some match bullets to be very consistent from the ogive to the lands but have variations in the overall length of the bullet. It seems that it's more difficult for the manufacturers to get the bullet tips consistent. This will give variations in yor distance to the lands. Tools are available that allow you to measure on the ogive for a particular caliber. I use a simple one that is shaped like a hex nut with a variety of holes on each flat to measure the popular calibers. it can be used with a standard caliper and allows me to measure to .001". Hope this helps.
     

  3. justinp61

    justinp61 Well-Known Member

    Messages:
    65
    Joined:
    Jul 31, 2011
    Who makes the tool you use to measure to the ogive?

    Thanks
     
  4. boomtube

    boomtube Well-Known Member

    Messages:
    1,595
    Joined:
    Oct 8, 2007
    There is no 'rule' for bullet seating and OAL is simply another way of expressing the seating depth. The jump to the lands is what ever we make it.

    Contrary to conventional 'wisdom', few factory sporters shoot their best at or really close to the lands. Most do best with a jump from 20 thou off the lands to as much as five times that much. Pick a depth where you want to start develop your charge, then experiment with seating changes in maybe 5 thou steps until you find the best shooting combination for your rig. I like to start maybe 15 thou off but that's just a convient place, others do it differently.

    Ogive measurement tools are supplied by Sinclair, RCBS (Precision Case Mic), Innovative Technologies and Hornady.
     
  5. Mikecr

    Mikecr Well-Known Member

    Messages:
    4,248
    Joined:
    Aug 10, 2003
  6. bowhunthard

    bowhunthard Well-Known Member

    Messages:
    978
    Joined:
    Sep 5, 2008
    First of all, oal and the distance to the lands are related, one affects the other. OAL is usually listed as the recommended length to fit in all firearms of that chambering. A load with a short jump to the lands will usually result in a longer than SAAMI spec (manual listing) oal. Most factory rifles seem to like the jump to the lands at about 0.020 - 0.050", in my personal experience. I do have some that are shorter and some that are longer though).

    Another side note is that different bullets will have different "jump to the lands" length, due to different ogive shapes.

    My findings with the 55 gr. V-Max was about 0.030" jump in my 22-250, but the actual oal for the same jump can differ in each rifle, as it depends on how long the throat of that particular rifle is.

    Good luck.
     
  7. RT2506

    RT2506 Well-Known Member

    Messages:
    1,498
    Joined:
    Jan 10, 2008
    Hornady makes the tool that measures from the Ogive of the bullet to the base of the case. The Ogive is the place on the bullet where it will contact the lands first. The tool is called Hornady Lock-N-Load Bullet Comparator at (Midway midwayusa.com it is product number 709-931). It attaches to a dial calipers. To help you find the measurement of where your particular bullet is hitting the lands in your rifle take a case and full length size it. Then take a cutting tool like a hack saw etc. and cut one side of the neck on the case down to the start of the shoulder. Clean up the burrs. Before every use run it into your size die or just pinch the neck tighter with your fingers. The cut in the side of the neck will allow the neck to flex and allow a bullet to be placed by hand into it and allow you to pull it out after use. As you did before just start the bullet into the case and place in the chamber and close the bolt. Ease the bolt open and carefully remove the case. Carefully measure using the comparator. This is your to the lands measurement to the Ogive of the bullet. Now you can seat deeper etc. and know were your are all the time. If you just measure from the bullet tips as an over all length you will never know exactly how far off the lands you really are. Bullet tips are often NOT the same length but from the base of the bullet to the Ogive it is always the same if the bullets were made on the same machine.
     
  8. longnkrnch

    longnkrnch Member

    Messages:
    5
    Joined:
    Apr 7, 2009
    Ok, this is sounding complicated. Right or wrong, this is what I have done in my bolt guns: I seat the given bullet long, then color it over with a magic marker. T then chamber and eject and observe for rifling marks. If present, I seat a few thousands more and repeat. I do this until no rifling marks appear. If the round operates in the magazine ok, I stop there. Not sure if this method is perfect, but it seems to get me some good accuracy. Feedback would be appreciated.
     
  9. Tumbleweed

    Tumbleweed Well-Known Member

    Messages:
    452
    Joined:
    Oct 20, 2007
    This is similar to how I find the rifling in a particular rifle as well. I make sure and use a fire formed case and FL size just enough to allow it to chamber ok, this way the shell fits the chamber much better and the bullet will be more centered to the rifling. After seeing rifling marks in the sharpie band that I've colored around the bullet I continue seating deeper in small increments until the marks are so faint they are almost not visible in the black sharpie band. This is my max length to touch the rifling or "0" (No jump and no jam) Now I have a reference or starting point to work from to set up my jump or some even like a little jam.
     
  10. longnkrnch

    longnkrnch Member

    Messages:
    5
    Joined:
    Apr 7, 2009
    Thanks for the response. I have not gone beyond what I originally posted and experimented with any other depths beyond "just off the lands". The particular rifle I spoke of shoots sub MOA with what I have done, so im satisfied wit that for hunting. I also load for my brother in law and often just give him some of my loads, but, have to put them back in the press and seat deeper for his rifle (same model as mine) because if not they will jam in the lands and pull the bullet out on extraction. I keep a dummy round with his name on it to set the seating die with when supplying him with ammo.:)